RHEL 8.5 - Administration and Configuration Tasks Using System Roles

Red Hat Enterprise Linux 8
Administration and configuration tasks using

System Roles in RHEL
Applying RHEL System Roles using Red Hat Ansible Automation Platform playbooks
to perform system administration tasks
Last Updated: 2022-01-26

Red Hat Enterprise Linux 8 Administration and configuration tasks using
System Roles in RHEL
Applying RHEL System Roles using Red Hat Ansible Automation Platform playbooks to perform
system administration tasks
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Abstract
This document describes configuring system roles using Ansible on Red Hat Enterprise Linux 8. The
title focuses on: the RHEL System Roles are a collection of Ansible roles, modules, and playbooks
that provide a stable and consistent configuration interface to manage and configure Red Hat
Enterprise Linux. They are designed to be forward compatible with multiple major release versions
of Red Hat Enterprise Linux 8.
Table of Contents
Table of Contents
. . . . . . . . . .OPEN
MAKING . . . . . . SOURCE
. . . . . . . . . .MORE
. . . . . . .INCLUSIVE
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5. . . . . . . . . . . . .
. . . . . . . . . . . . . FEEDBACK
PROVIDING . . . . . . . . . . . . ON
. . . .RED
. . . . .HAT
. . . . .DOCUMENTATION
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6. . . . . . . . . . . . .
.CHAPTER
. . . . . . . . . . 1.. .GETTING
. . . . . . . . . . STARTED
. . . . . . . . . . .WITH
. . . . . .RHEL
. . . . . .SYSTEM
. . . . . . . . .ROLES
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7. . . . . . . . . . . . .
1.1. INTRODUCTION TO RHEL SYSTEM ROLES 7
1.2. RHEL SYSTEM ROLES TERMINOLOGY 7
1.3. APPLYING A ROLE 8
1.4. ADDITIONAL RESOURCES 10
. . . . . . . . . . . 2.
CHAPTER . . INSTALLING
. . . . . . . . . . . . . .RHEL
. . . . . . SYSTEM
. . . . . . . . . ROLES
. . . . . . . . IN
. . .YOUR
. . . . . . SYSTEM
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .11. . . . . . . . . . . . .
.CHAPTER
. . . . . . . . . . 3.
. . INSTALLING
. . . . . . . . . . . . . .AND
. . . . . USING
. . . . . . . COLLECTIONS
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
..............
3.1. INTRODUCTION TO ANSIBLE COLLECTIONS 12
3.2. COLLECTIONS STRUCTURE 12
3.3. INSTALLING COLLECTIONS BY USING THE CLI 12
3.4. INSTALLING COLLECTIONS FROM AUTOMATION HUB 13
3.5. APPLYING A LOCAL LOGGING SYSTEM ROLE USING COLLECTIONS 14
.CHAPTER
. . . . . . . . . . 4.
. . .USING
. . . . . . .ANSIBLE
. . . . . . . . . .ROLES
. . . . . . . TO
. . . .PERMANENTLY
. . . . . . . . . . . . . . . . .CONFIGURE
. . . . . . . . . . . . . KERNEL
. . . . . . . . . PARAMETERS
. . . . . . . . . . . . . . . . . . . . . . . . . . . 17
..............
4.1. INTRODUCTION TO THE KERNEL SETTINGS ROLE 17
4.2. APPLYING SELECTED KERNEL PARAMETERS USING THE KERNEL SETTINGS ROLE 17
.CHAPTER
. . . . . . . . . . 5.
. . USING
. . . . . . . .SYSTEM
. . . . . . . . .ROLES
. . . . . . . .TO
. . . CONFIGURE
. . . . . . . . . . . . . .NETWORK
. . . . . . . . . . . CONNECTIONS
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
..............
5.1. CONFIGURING A STATIC ETHERNET CONNECTION USING RHEL SYSTEM ROLES WITH THE INTERFACE
NAME 21
5.2. CONFIGURING A DYNAMIC ETHERNET CONNECTION USING RHEL SYSTEM ROLES WITH THE
INTERFACE NAME 22
5.3. CONFIGURING VLAN TAGGING USING SYSTEM ROLES 24
5.4. CONFIGURING A NETWORK BRIDGE USING RHEL SYSTEM ROLES 25
5.5. CONFIGURING A NETWORK BOND USING RHEL SYSTEM ROLES 27
5.6. CONFIGURING A STATIC ETHERNET CONNECTION WITH 802.1X NETWORK AUTHENTICATION USING
RHEL SYSTEM ROLES 29
5.7. SETTING THE DEFAULT GATEWAY ON AN EXISTING CONNECTION USING SYSTEM ROLES 31
5.8. CONFIGURING A STATIC ROUTE USING RHEL SYSTEM ROLES 33
5.9. USING SYSTEM ROLES TO SET ETHTOOL FEATURES 35
5.10. USING SYSTEM ROLES TO CONFIGURE ETHTOOL COALESCE SETTINGS 37
.CHAPTER
. . . . . . . . . . 6.
. . .POSTFIX
. . . . . . . . . ROLE
. . . . . . .VARIABLES
. . . . . . . . . . . . IN
. . .SYSTEM
. . . . . . . . . ROLES
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .40
..............
.CHAPTER
. . . . . . . . . . 7.
. . CONFIGURING
. . . . . . . . . . . . . . . . SELINUX
. . . . . . . . . . USING
. . . . . . . SYSTEM
. . . . . . . . . .ROLES
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41
..............
7.1. INTRODUCTION TO THE SELINUX SYSTEM ROLE 41
7.2. USING THE SELINUX SYSTEM ROLE TO APPLY SELINUX SETTINGS ON MULTIPLE SYSTEMS 42
.CHAPTER
. . . . . . . . . . 8.
. . .USING
. . . . . . .THE
. . . . .LOGGING
. . . . . . . . . . .SYSTEM
. . . . . . . . .ROLE
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .44
..............
8.1. THE LOGGING SYSTEM ROLE 44
8.2. LOGGING SYSTEM ROLE PARAMETERS 44
8.3. APPLYING A LOCAL LOGGING SYSTEM ROLE 45
8.4. FILTERING LOGS IN A LOCAL LOGGING SYSTEM ROLE 47
8.5. APPLYING A REMOTE LOGGING SOLUTION USING THE LOGGING SYSTEM ROLE 49
.CHAPTER
. . . . . . . . . . 9.
. . .CONFIGURING
. . . . . . . . . . . . . . . SECURE
. . . . . . . . . .COMMUNICATION
. . . . . . . . . . . . . . . . . . . WITH
. . . . . . THE
. . . . .SSH
. . . . .SYSTEM
. . . . . . . . . ROLES
. . . . . . . . . . . . . . . . . . . . . . . . .53
..............
9.1. SSHD SYSTEM ROLE VARIABLES 53
1
Red Hat Enterprise Linux 8 Administration and configuration tasks using System Roles in RHEL
9.2. CONFIGURING OPENSSH SERVERS USING THE SSHD SYSTEM ROLE 55

9.3. SSH SYSTEM ROLE VARIABLES 58
9.4. CONFIGURING OPENSSH CLIENTS USING THE SSH SYSTEM ROLE 59
9.5. USING THE SSH SERVER SYSTEM ROLE FOR NON-EXCLUSIVE CONFIGURATION 61
. . . . . . . . . . . 10.
CHAPTER . . . CONFIGURING
. . . . . . . . . . . . . . . . VPN
. . . . . CONNECTIONS
. . . . . . . . . . . . . . . . .WITH
. . . . . .IPSEC
. . . . . . .BY
. . . USING
. . . . . . . THE
. . . . . RHEL
. . . . . . VPN
. . . . . SYSTEM
. . . . . . . . . .ROLE
.....................
63
10.1. CREATING A HOST-TO-HOST VPN WITH IPSEC USING THE VPN SYSTEM ROLE 63
10.2. CREATING AN OPPORTUNISTIC MESH VPN CONNECTION WITH IPSEC BY USING THE VPN SYSTEM
ROLE 65
.CHAPTER
. . . . . . . . . . 11.
. . .SETTING
. . . . . . . . . .A. CUSTOM
. . . . . . . . . . CRYPTOGRAPHIC
. . . . . . . . . . . . . . . . . . . .POLICY
. . . . . . . . ACROSS
. . . . . . . . . .SYSTEMS
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .68
..............
11.1. CRYPTO POLICIES SYSTEM ROLE VARIABLES AND FACTS 68
11.2. SETTING A CUSTOM CRYPTOGRAPHIC POLICY USING THE CRYPTO POLICIES SYSTEM ROLE 68
.CHAPTER
. . . . . . . . . . 12.
. . . USING
. . . . . . . THE
. . . . . CLEVIS
. . . . . . . . AND
. . . . . .TANG
. . . . . . SYSTEM
. . . . . . . . . .ROLES
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 71
..............
12.1. INTRODUCTION TO THE CLEVIS AND TANG SYSTEM ROLES 71
12.2. USING THE NBDE_SERVER SYSTEM ROLE FOR SETTING UP MULTIPLE TANG SERVERS 71
12.3. USING THE NBDE_CLIENT SYSTEM ROLE FOR SETTING UP MULTIPLE CLEVIS CLIENTS 73
. . . . . . . . . . . 13.
CHAPTER . . . REQUESTING
. . . . . . . . . . . . . . .CERTIFICATES
. . . . . . . . . . . . . . . .USING
. . . . . . .RHEL
. . . . . . SYSTEM
. . . . . . . . . ROLES
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .75
..............
13.1. THE CERTIFICATE SYSTEM ROLE 75
13.2. REQUESTING A NEW SELF-SIGNED CERTIFICATE USING THE CERTIFICATE SYSTEM ROLE 75
13.3. REQUESTING A NEW CERTIFICATE FROM IDM CA USING THE CERTIFICATE SYSTEM ROLE 77
13.4. SPECIFYING COMMANDS TO RUN BEFORE OR AFTER CERTIFICATE ISSUANCE USING THE
CERTIFICATE SYSTEM ROLE 78
.CHAPTER
. . . . . . . . . . 14.
. . . CONFIGURING
. . . . . . . . . . . . . . . . KDUMP
. . . . . . . . .USING
. . . . . . .RHEL
. . . . . . SYSTEM
. . . . . . . . . ROLES
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 81
..............
14.1. THE KDUMP RHEL SYSTEM ROLE 81
14.2. KDUMP ROLE PARAMETERS 81
14.3. CONFIGURING KDUMP USING RHEL SYSTEM ROLES 81
. . . . . . . . . . . 15.
CHAPTER . . . MANAGING
. . . . . . . . . . . . .LOCAL
. . . . . . . .STORAGE
. . . . . . . . . . .USING
. . . . . . .RHEL
. . . . . . SYSTEM
. . . . . . . . . ROLES
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .83
..............
15.1. INTRODUCTION TO THE STORAGE ROLE 83
15.2. PARAMETERS THAT IDENTIFY A STORAGE DEVICE IN THE STORAGE SYSTEM ROLE 83
15.3. EXAMPLE ANSIBLE PLAYBOOK TO CREATE AN XFS FILE SYSTEM ON A BLOCK DEVICE 84
15.4. EXAMPLE ANSIBLE PLAYBOOK TO PERSISTENTLY MOUNT A FILE SYSTEM 85
15.5. EXAMPLE ANSIBLE PLAYBOOK TO MANAGE LOGICAL VOLUMES 85
15.6. EXAMPLE ANSIBLE PLAYBOOK TO ENABLE ONLINE BLOCK DISCARD 86
15.7. EXAMPLE ANSIBLE PLAYBOOK TO CREATE AND MOUNT AN EXT4 FILE SYSTEM 87
15.8. EXAMPLE ANSIBLE PLAYBOOK TO CREATE AND MOUNT AN EXT3 FILE SYSTEM 87
15.9. EXAMPLE ANSIBLE PLAYBOOK TO RESIZE AN EXISTING EXT4 OR EXT3 FILE SYSTEM USING THE
STORAGE RHEL SYSTEM ROLE 88
15.10. EXAMPLE ANSIBLE PLAYBOOK TO RESIZE AN EXISTING FILE SYSTEM ON LVM USING THE STORAGE
RHEL SYSTEM ROLE 89
15.11. EXAMPLE ANSIBLE PLAYBOOK TO CREATE A SWAP PARTITION USING THE STORAGE RHEL SYSTEM
ROLE 90
15.12. CONFIGURING A RAID VOLUME USING THE STORAGE SYSTEM ROLE 91
15.13. CONFIGURING AN LVM POOL WITH RAID USING THE STORAGE SYSTEM ROLE 92
15.14. EXAMPLE ANSIBLE PLAYBOOK TO COMPRESS AND DEDUPLICATE A VDO VOLUME ON LVM USING
THE STORAGE RHEL SYSTEM ROLE 93
15.15. CREATING A LUKS ENCRYPTED VOLUME USING THE STORAGE ROLE 94
15.16. EXAMPLE ANSIBLE PLAYBOOK TO EXPRESS POOL VOLUME SIZES AS PERCENTAGE USING THE
STORAGE RHEL SYSTEM ROLE 95
2
Table of Contents
. . . . . . . . . . . 16.
. . . . . . . . . . . . . . . . TIME
. . . . . .SYNCHRONIZATION
. . . . . . . . . . . . . . . . . . . . . USING
. . . . . . . .RHEL
. . . . . .SYSTEM
. . . . . . . . . ROLES
. . . . . . . . . . . . . . . . . . . . . . . . . . . .96
..............
16.1. THE TIMESYNC SYSTEM ROLE 96
16.2. APPLYING THE TIMESYNC SYSTEM ROLE FOR A SINGLE POOL OF SERVERS 96
16.3. APPLYING THE TIMESYNC SYSTEM ROLE ON CLIENT SERVERS 97
16.4. TIMESYNC SYSTEM ROLES VARIABLES 98
. . . . . . . . . . . 17.
CHAPTER . . . MONITORING
. . . . . . . . . . . . . . .PERFORMANCE
. . . . . . . . . . . . . . . . . USING
. . . . . . . RHEL
. . . . . . .SYSTEM
. . . . . . . . .ROLES
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .100
...............
17.1. INTRODUCTION TO THE METRICS SYSTEM ROLE 100
17.2. USING THE METRICS SYSTEM ROLE TO MONITOR YOUR LOCAL SYSTEM WITH VISUALIZATION 101
17.3. USING THE METRICS SYSTEM ROLE TO SETUP A FLEET OF INDIVIDUAL SYSTEMS TO MONITOR
THEMSELVES 101
17.4. USING THE METRICS SYSTEM ROLE TO MONITOR A FLEET OF MACHINES CENTRALLY VIA YOUR
LOCAL MACHINE 102
17.5. SETTING UP AUTHENTICATION WHILE MONITORING A SYSTEM USING THE METRICS SYSTEM ROLE
103
17.6. USING THE METRICS SYSTEM ROLE TO CONFIGURE AND ENABLE METRICS COLLECTION FOR SQL
SERVER 104
. . . . . . . . . . . 18.
. . . . . . . . . . . . . . . . MICROSOFT
. . . . . . . . . . . . . .SQL
. . . . .SERVER
. . . . . . . . USING
. . . . . . . .MICROSOFT.SQL.SERVER
. . . . . . . . . . . . . . . . . . . . . . . . . . . ANSIBLE
. . . . . . . . . .ROLE
....................
106
18.1. PREREQUISITES 106
18.2. INSTALLING MICROSOFT.SQL.SERVER ANSIBLE ROLE 106
18.3. INSTALLING AND CONFIGURING SQL SERVER USING MICROSOFT.SQL.SERVER ANSIBLE ROLE 107
18.4. TLS VARIABLES 107
18.5. ACCEPTING EULA FOR MLSERVICES 108
18.6. ACCEPTING EULAS FOR MICROSOFT ODBC 17 109
CHAPTER 19. CONFIGURING A SYSTEM FOR SESSION RECORDING USING THE TLOG RHEL SYSTEM
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 110
ROLES ...............
19.1. THE TLOG SYSTEM ROLE 110
19.2. COMPONENTS AND PARAMETERS OF THE TLOG SYSTEM ROLES 110
19.3. DEPLOYING THE TLOG RHEL SYSTEM ROLE 110
19.4. DEPLOYING THE TLOG RHEL SYSTEM ROLE FOR EXCLUDING LISTS OF GROUPS OR USERS 112
19.5. RECORDING A SESSION USING THE DEPLOYED TLOG SYSTEM ROLE IN THE CLI 113
19.6. WATCHING A RECORDED SESSION USING THE CLI 114
.CHAPTER
. . . . . . . . . . 20.
. . . .CONFIGURING
. . . . . . . . . . . . . . . .A. .HIGH-AVAILABILITY
. . . . . . . . . . . . . . . . . . . . . CLUSTER
. . . . . . . . . . .USING
. . . . . . . SYSTEM
. . . . . . . . . ROLES
. . . . . . . . . . . . . . . . . . . . . . . . . . .116
..............
20.1. HA_CLUSTER SYSTEM ROLE VARIABLES 116
20.2. SPECIFYING AN INVENTORY FOR THE HA_CLUSTER SYSTEM ROLE 122
20.3. CONFIGURING A HIGH AVAILABILITY CLUSTER RUNNING NO RESOURCES 122
20.4. CONFIGURING A HIGH AVAILABILITY CLUSTER WITH FENCING AND RESOURCES 123
20.5. CONFIGURING AN APACHE HTTP SERVER IN A HIGH AVAILABILITY CLUSTER WITH THE HA_CLUSTER
SYSTEM ROLE 126
3
4
MAKING OPEN SOURCE MORE INCLUSIVE
MAKING OPEN SOURCE MORE INCLUSIVE

Red Hat is committed to replacing problematic language in our code, documentation, and web
properties. We are beginning with these four terms: master, slave, blacklist, and whitelist. Because of the
enormity of this endeavor, these changes will be implemented gradually over several upcoming releases.
For more details, see our CTO Chris Wright’s message .
5
PROVIDING FEEDBACK ON RED HAT DOCUMENTATION

We appreciate your input on our documentation. Please let us know how we could make it better. To do
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For simple comments on specific passages:
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ensure you see the Feedback button in the upper right corner of the document.
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6
CHAPTER 1. GETTING STARTED WITH RHEL SYSTEM ROLES

This section explains what RHEL System Roles are. Additionally, it describes how to apply a particular
role through an Ansible playbook to perform various system administration tasks.
1.1. INTRODUCTION TO RHEL SYSTEM ROLES

RHEL System Roles is a collection of Ansible roles and modules. RHEL System Roles provide a
configuration interface to remotely manage multiple RHEL systems. The interface enables managing
system configurations across multiple versions of RHEL, as well as adopting new major releases.
On Red Hat Enterprise Linux 8, the interface currently consists of the following roles:
kdump
network
selinux
storage
certificate
kernel_settings
logging
metrics
nbde_client and nbde_server
timesync
tlog
All these roles are provided by the rhel-system-roles package available in the AppStream repository.
Additional resources
Red Hat Enterprise Linux (RHEL) System Roles
/usr/share/doc/rhel-system-roles documentation [1]
Introduction to the SELinux system role
Introduction to the storage role
Administration and configuration tasks using System Roles in RHEL
1.2. RHEL SYSTEM ROLES TERMINOLOGY

You can find the following terms across this documentation:
System Roles terminology
7
Ansible playbook
Playbooks are Ansible’s configuration, deployment, and orchestration language. They can describe a
policy you want your remote systems to enforce, or a set of steps in a general IT process.
Control node
Any machine with Ansible installed. You can run commands and playbooks, invoking /usr/bin/ansible
or /usr/bin/ansible-playbook, from any control node. You can use any computer that has Python
installed on it as a control node - laptops, shared desktops, and servers can all run Ansible. However,
you cannot use a Windows machine as a control node. You can have multiple control nodes.
Inventory
A list of managed nodes. An inventory file is also sometimes called a “hostfile”. Your inventory can
specify information like IP address for each managed node. An inventory can also organize managed
nodes, creating and nesting groups for easier scaling. To learn more about inventory, see the
Working with Inventory section.
Managed nodes
The network devices, servers, or both that you manage with Ansible. Managed nodes are also
sometimes called “hosts”. Ansible is not installed on managed nodes.
1.3. APPLYING A ROLE

The following procedure describes how to apply a particular role.
Prerequisites
Ensure that the rhel-system-roles package is installed on the system that you want to use as a
control node:
# yum install rhel-system-roles
You need the ansible package to run playbooks that use RHEL System Roles. Ensure that the
Ansible Engine repository is enabled, and the ansible package is installed on the system that
you want to use as a control node.
If you do not have a Red Hat Ansible Engine Subscription, you can use a limited supported
version of Red Hat Ansible Engine provided with your Red Hat Enterprise Linux subscription.
In this case, follow these steps:
1. Enable the RHEL Ansible Engine repository:
# subscription-manager refresh
# subscription-manager repos --enable ansible-2-for-rhel-8-x86_64-rpms
2. Install Ansible Engine:
# yum install ansible
If you have a Red Hat Ansible Engine Subscription, follow the procedure described in How
do I Download and Install Red Hat Ansible Engine?.
Ensure that you are able to create an Ansible inventory.

Inventories represent the hosts, host groups, and some of the configuration parameters used by
the Ansible playbooks.
Playbooks are typically human-readable, and are defined in ini, yaml, json, and other file
8
Playbooks are typically human-readable, and are defined in ini, yaml, json, and other file
formats.
Ensure that you are able to create an Ansible playbook.

Playbooks represent Ansible’s configuration, deployment, and orchestration language. By using
playbooks, you can declare and manage configurations of remote machines, deploy multiple
remote machines or orchestrate steps of any manual ordered process.
A playbook is a list of one or more plays. Every play can include Ansible variables, tasks, or roles.
Playbooks are human-readable, and are defined in the yaml format.
Procedure
1. Create the required Ansible inventory containing the hosts and groups that you want to
manage. Here is an example using a file called inventory.ini of a group of hosts called
webservers:
[webservers]
host1
host2
host3
2. Create an Ansible playbook including the required role. The following example shows how to use
roles through the roles: option for a playbook:
The following example shows how to use roles through the roles: option for a given play:
---
- hosts: webservers
roles:
- rhel-system-roles.network
- rhel-system-roles.timesync
NOTE
Every role includes a README file, which documents how to use the role and
supported parameter values. You can also find an example playbook for a
particular role under the documentation directory of the role. Such
documentation directory is provided by default with the rhel-system-roles
package, and can be found in the following location:
/usr/share/doc/rhel-system-roles/SUBSYSTEM/
Replace SUBSYSTEM with the name of the required role, such as selinux,
kdump, network, timesync, or storage.
3. To execute the playbook on specific hosts, you must perform one of the following:
Edit the playbook to use hosts: host1[,host2,…], or hosts: all, and execute the command:
# ansible-playbook name.of.the.playbook
Edit the inventory to ensure that the hosts you want to use are defined in a group, and
execute the command:
9
# ansible-playbook -i name.of.the.inventory name.of.the.playbook
Specify all hosts when executing the ansible-playbook command:
# ansible-playbook -i host1,host2,... name.of.the.playbook
IMPORTANT
Be aware that the -i flag specifies the inventory of all hosts that are available.
If you have multiple targeted hosts, but want to select a host against which
you want to run the playbook, you can add a variable in the playbook to be
able to select a host. For example:
Ansible Playbook | example-playbook.yml:
- hosts: "{{ target_host }}"

roles:
- rhel-system-roles.network
Playbook execution command:
# ansible-playbook -i host1,..hostn -e target_host=host5 example-

playbook.yml
Ansible playbooks
Using roles in Ansible playbook
Examples of Ansible playbooks
How to create and work with inventory?
ansible-playbook
1.4. ADDITIONAL RESOURCES

Red Hat Enterprise Linux (RHEL) System Roles
Managing local storage using RHEL System Roles
Deploying the same SELinux configuration on multiple systems using RHEL System Roles
[1] This documentation is installed automatically with the rhel-system-roles package.
10
CHAPTER 2. INSTALLING RHEL SYSTEM ROLES IN YOUR SYSTEM
CHAPTER 2. INSTALLING RHEL SYSTEM ROLES IN YOUR

SYSTEM
To use the RHEL System Roles, install the required packages in your system.
Prerequisites
You have a Red Hat Ansible Engine Subscription. See the procedure How do I Download and
Install Red Hat Ansible Engine?
You have Ansible packages installed in the system you want to use as a control node:
Procedure
1. Install the rhel-system-roles package on the system that you want to use as a control node:
If you do not have a Red Hat Ansible Engine Subscription, you can use a limited supported
version of Red Hat Ansible Engine provided with your Red Hat Enterprise Linux subscription. In
this case, follow these steps:
a. Enable the RHEL Ansible Engine repository:
b. Install Ansible Engine:
As a result, you are able to create an Ansible playbook.
The Red Hat Enterprise Linux (RHEL) System Roles
The ansible-playbook man page.
11
CHAPTER 3. INSTALLING AND USING COLLECTIONS
3.1. INTRODUCTION TO ANSIBLE COLLECTIONS

Ansible Collections are the new way of distributing, maintaining, and consuming automation. By
combining multiple types of Ansible content such as playbooks, roles, modules, and plugins, you can
benefit from improvements in flexibility and scalability.
The Ansible Collections are an option to the traditional RHEL System Roles format. Using the RHEL
System Roles in the Ansible Collection format is almost the same as using it in the traditional RHEL
System Roles format. The difference is that Ansible Collections use the concept of a fully qualified
collection name (FQCN), which consists of a namespace and the collection name. The namespace
we use is redhat and the collection name is rhel_system_roles. So, while the traditional RHEL System
Roles format for the Kernel role is presented as rhel-system-roles.kernel_settings, using the
Collection fully qualified collection name for the Kernel role would be presented as
redhat.rhel_system_roles.kernel_settings.
The combination of a namespace and a collection name guarantees that the objects are unique. It also
ensures that objects are shared across the Ansible Collections and namespaces without any conflicts.
You can find the Red Hat Certified Collections by accessing the Automation Hub.
3.2. COLLECTIONS STRUCTURE

Collections are a package format for Ansible content. The data structure is as below:
docs/: local documentation for the collection, with examples, if the role provides the
documentation
galaxy.yml: source data for the MANIFEST.json that will be part of the Ansible Collection
package
playbooks/: playbooks are available here
tasks/: this holds 'task list files' for include_tasks/import_tasks usage
plugins/: all Ansible plugins and modules are available here, each in its subdirectory
modules/: Ansible modules
modules_utils/: common code for developing modules
lookup/: search for a plugin
filter/: Jinja2 filter plugin
connection/: connection plugins required if not using the default
roles/: directory for Ansible roles
tests/: tests for the collection’s content
3.3. INSTALLING COLLECTIONS BY USING THE CLI
12
Collections are a distribution format for Ansible content that can include playbooks, roles, modules, and
plugins.
You can install Collections through Ansible Galaxy, through the browser, or by using the command line.
Prerequisites
Red Hat Ansible Engine version 2.9 and later is installed.
The python3-jmespath package is installed.
An inventory file that lists the managed nodes exists.
Procedure
Install the collection via RPM package:
After the installation is finished, the roles are available as redhat.rhel_system_roles.<role_name>.

Additionally, you can find the documentation for each role at
/usr/share/ansible/collections/ansible_collections/redhat/rhel_system_roles/roles/<role_name>/R
EADME.md.
Verification steps
To verify that the Collections were successfully installed, you can apply the kernel_settings on your
localhost:
1. Copy one of the tests_default.yml to your working directory.
$ cp
/usr/share/ansible/collections/ansible_collections/redhat/rhel_system_roles/tests/kernel_settings/t
ests_default.yml .
2. Edit the file, replacing "hosts: all" with "hosts: localhost" to make the playbook run only on the
local system.
3. Run the ansible-playbook in the check mode. This does not change any settings on your system.
$ ansible-playbook --check tests_default.yml
The command returns the value failed=0.
3.4. INSTALLING COLLECTIONS FROM AUTOMATION HUB

If you are using the Automation Hub, you can install the System Roles Collection hosted on the
Automation Hub.
Prerequisites
13
Red Hat Ansible Engine version 2.9 or later is installed.
Red Hat Ansible Automation Platform subscription.
The python3-jmespath package is installed.
An inventory file that lists the managed nodes exists.
Procedure
1. Define Red Hat Automation Hub as the default source for content in the ansible.cfg
configuration file. See Configuring Red Hat Automation Hub as the primary source for content .
2. Install the redhat.rhel_system_roles collection from the Automation Hub:
# ansible-galaxy collection install redhat.rhel_system_roles
After the installation is finished, the roles are available as redhat.rhel_system_roles.

<role_name>. Additionally, you can find the documentation for each role at
/usr/share/ansible/collections/ansible_collections/redhat/rhel_system_roles/roles/<role_n
ame>/README.md.
Verification steps
To verify that the Collections were successfully installed, you can apply the kernel_settings on your
localhost:
1. Copy one of the tests_default.yml to your working directory.
$ cp
/usr/share/ansible/collections/ansible_collections/redhat/rhel_system_roles/tests/kernel_settings/t
ests_default.yml .
2. Edit the file, replacing "hosts: all" with "hosts: localhost" to make the playbook run only on the
local system.
3. Run the ansible-playbook on the check mode. This does not change any settings on your
system.
$ ansible-playbook --check tests_default.yml
You can see the command returns with the value failed=0.
3.5. APPLYING A LOCAL LOGGING SYSTEM ROLE USING

COLLECTIONS
Following is an example using Collections to prepare and apply a Red Hat Ansible Engine playbook to
configure a logging solution on a set of separate machines.
Prerequisites
14
A Galaxy collection is installed.
Procedure
1. Create a playbook that defines the required role:
a. Create a new YAML file and open it in a text editor, for example:
# vi logging-playbook.yml
b. Insert the following content into the YAML file:
---
- name: Deploying basics input and implicit files output
hosts: all
roles:
- redhat.rhel_system_roles.logging
vars:
logging_inputs:
- name: system_input
type: basics
logging_outputs:
- name: files_output
type: files
logging_flows:
- name: flow1
inputs: [system_input]
outputs: [files_output]
2. Execute the playbook on a specific inventory:
# ansible-playbook -i inventory-file logging-playbook.yml
Where:
inventory-file is the name of your inventory file.
logging-playbook.yml is the playbook you use.
Verification steps
1. Test the syntax of the /etc/rsyslog.conf file:
# rsyslogd -N 1
rsyslogd: version 8.1911.0-6.el8, config validation run (level 1), master config
/etc/rsyslog.conf
rsyslogd: End of config validation run. Bye.
2. Verify that the system sends messages to the log:
a. Send a test message:
# logger test
15
b. View the /var/log/messages log, for example:
# cat /var/log/messages
Aug 5 13:48:31 hostname root[6778]: test
The hostname is the hostname of the client system. The log displays the user name of the
user that entered the logger command, in this case, root.
16
CHAPTER 4. USING ANSIBLE ROLES TO PERMANENTLY CONFIGURE KERNEL PARAMETERS
CHAPTER 4. USING ANSIBLE ROLES TO PERMANENTLY

CONFIGURE KERNEL PARAMETERS
As an experienced user with good knowledge of Red Hat Ansible Engine, you can use the
kernel_settings role to configure kernel parameters on multiple clients at once. This solution:
Provides a friendly interface with efficient input setting.
Keeps all intended kernel parameters in one place.
After you run the kernel_settings role from the control machine, the kernel parameters are applied to
the managed systems immediately and persist across reboots.
4.1. INTRODUCTION TO THE KERNEL SETTINGS ROLE

RHEL System Roles is a collection of roles and modules from Ansible Automation Platform that provide
a consistent configuration interface to remotely manage multiple systems.
RHEL System Roles were introduced for automated configurations of the kernel using the
kernel_settings system role. The rhel-system-roles package contains this system role, and also the
reference documentation.
To apply the kernel parameters on one or more systems in an automated fashion, use the
kernel_settings role with one or more of its role variables of your choice in a playbook. A playbook is a
list of one or more plays that are human-readable, and are written in the YAML format.
You can use an inventory file to define a set of systems that you want Ansible Engine to configure
according to the playbook.
With the kernel_settings role you can configure:
The kernel parameters using the kernel_settings_sysctl role variable
Various kernel subsystems, hardware devices, and device drivers using the
kernel_settings_sysfs role variable
The CPU affinity for the systemd service manager and processes it forks using the
kernel_settings_systemd_cpu_affinity role variable
The kernel memory subsystem transparent hugepages using the

kernel_settings_transparent_hugepages and
kernel_settings_transparent_hugepages_defrag role variables
README.md and README.html files in the /usr/share/doc/rhel-system-

roles/kernel_settings/ directory
Working with playbooks
How to build your inventory
4.2. APPLYING SELECTED KERNEL PARAMETERS USING THE KERNEL

SETTINGS ROLE
17
Follow these steps to prepare and apply an Ansible playbook to remotely configure kernel parameters
with persisting effect on multiple managed operating systems.
Prerequisites
Your Red Hat Ansible Engine subscription is attached to the system, also called control machine,
from which you want to run the kernel_settings role. See the How do I download and install Red
Hat Ansible Engine article for more information.
Ansible Engine repository is enabled on the control machine.
Ansible Engine is installed on the control machine.
NOTE
You do not need to have Ansible Engine installed on the systems, also called
managed hosts, where you want to configure the kernel parameters.
The rhel-system-roles package is installed on the control machine.
An inventory of managed hosts is present on the control machine and Ansible Engine is able to
connect to them.
Procedure
1. Optionally, review the inventory file for illustration purposes:
# cat /home/jdoe/<ansible_project_name>/inventory
[testingservers]
pdoe@192.168.122.98
fdoe@192.168.122.226
[db-servers]
db1.example.com
db2.example.com
[webservers]
web1.example.com
web2.example.com
192.0.2.42
The file defines the [testingservers] group and other groups. It allows you to run Ansible Engine
more effectively against a specific collection of systems.
2. Create a configuration file to set defaults and privilege escalation for Ansible Engine operations.
# vi /home/jdoe/<ansible_project_name>/ansible.cfg
b. Insert the following content into the file:
[defaults]
inventory = ./inventory
18
CHAPTER 4. USING ANSIBLE ROLES TO PERMANENTLY CONFIGURE KERNEL PARAMETERS
[privilege_escalation]
become = true
become_method = sudo
become_user = root
become_ask_pass = true
The [defaults] section specifies a path to the inventory file of managed hosts. The
[privilege_escalation] section defines that user privileges be shifted to root on the
specified managed hosts. This is necessary for successful configuration of kernel
parameters. When Ansible playbook is run, you will be prompted for user password. The user
automatically switches to root by means of sudo after connecting to a managed host.
3. Create an Ansible playbook that uses the kernel_settings role.
# vi /home/jdoe/<ansible_project_name>/kernel-roles.yml
This file represents a playbook and usually contains an ordered list of tasks, also called plays,
that are run against specific managed hosts selected from your inventory file.
---
- name: Configure kernel settings
hosts: testingservers
vars:
kernel_settings_sysctl:
- name: fs.file-max
value: 400000
- name: kernel.threads-max
value: 65536
kernel_settings_sysfs:
- name: /sys/class/net/lo/mtu
value: 65000
kernel_settings_transparent_hugepages: madvise
roles:
- rhel-system-roles.kernel_settings
The name key is optional. It associates an arbitrary string with the play as a label and
identifies what the play is for. The hosts key in the play specifies the hosts against which
the play is run. The value or values for this key can be provided as individual names of
managed hosts or as groups of hosts as defined in the inventory file.
The vars section represents a list of variables containing selected kernel parameter names
and values to which they have to be set.
The roles key specifies what system role is going to configure the parameters and values
mentioned in the vars section.
NOTE
You can modify the kernel parameters and their values in the playbook to fit
your needs.
19
4. Optionally, verify that the syntax in your play is correct.
# ansible-playbook --syntax-check kernel-roles.yml
playbook: kernel-roles.yml
This example shows the successful verification of a playbook.
5. Execute your playbook.
# ansible-playbook kernel-roles.yml
BECOME password:
PLAY [Configure kernel settings] ... PLAY RECAP **

fdoe@192.168.122.226 : ok=10 changed=4 unreachable=0 failed=0 skipped=6
rescued=0 ignored=0
pdoe@192.168.122.98 : ok=10 changed=4 unreachable=0 failed=0 skipped=6
rescued=0 ignored=0
Before Ansible Engine runs your playbook, you are going to be prompted for your password
and so that a user on managed hosts can be switched to root, which is necessary for
configuring kernel parameters.
The recap section shows that the play finished successfully (failed=0) for all managed
hosts, and that 4 kernel parameters have been applied (changed=4).
6. Restart your managed hosts and check the affected kernel parameters to verify that the
changes have been applied and persist across reboots.
Getting started with RHEL System Roles
README.html and README.md files in the /usr/share/doc/rhel-system-

roles/kernel_settings/ directory
Working with Inventory
Configuring Ansible
Working With Playbooks
Using Variables
Roles
20
CHAPTER 5. USING SYSTEM ROLES TO CONFIGURE NETWORK CONNECTIONS
CHAPTER 5. USING SYSTEM ROLES TO CONFIGURE

NETWORK CONNECTIONS
The network system role on RHEL enables administrators to automate network-related
configuration and management tasks using Ansible.
5.1. CONFIGURING A STATIC ETHERNET CONNECTION USING RHEL

SYSTEM ROLES WITH THE INTERFACE NAME
This procedure describes how to use the network RHEL System Role to remotely add an Ethernet
connection for the enp7s0 interface with the following settings by running an Ansible playbook:
A static IPv4 address - 192.0.2.1 with a /24 subnet mask
A static IPv6 address - 2001:db8:1::1 with a /64 subnet mask
An IPv4 default gateway - 192.0.2.254
An IPv6 default gateway - 2001:db8:1::fffe
An IPv4 DNS server - 192.0.2.200
An IPv6 DNS server - 2001:db8:1::ffbb
A DNS search domain - example.com
Run this procedure on the Ansible control node.
Prerequisites
The ansible and rhel-system-roles packages are installed on the control node.
If you use a different remote user than root when you run the playbook, this user has
appropriate sudo permissions on the managed node.
The host uses NetworkManager to configure the network.
Procedure
1. If the host on which you want to execute the instructions in the playbook is not yet
inventoried, add the IP or name of this host to the /etc/ansible/hosts Ansible inventory file:
node.example.com
2. Create the ~/ethernet-static-IP.yml playbook with the following content:
---
- name: Configure an Ethernet connection with static IP
hosts: node.example.com
become: true
tasks:
- include_role:
name: rhel-system-roles.network
21
vars:
network_connections:
- name: enp7s0
interface_name: enp7s0
type: ethernet
autoconnect: yes
ip:
address:
- 192.0.2.1/24
- 2001:db8:1::1/64
gateway4: 192.0.2.254
gateway6: 2001:db8:1::fffe
dns:
- 192.0.2.200
- 2001:db8:1::ffbb
dns_search:
- example.com
state: up
3. Run the playbook:
To connect as root user to the managed host, enter:
# ansible-playbook -u root ~/ethernet-static-IP.yml
To connect as a user to the managed host, enter:
# ansible-playbook -u user_name --ask-become-pass ~/ethernet-static-IP.yml
The --ask-become-pass option makes sure that theansible-playbook command

prompts for the sudo password of the user defined in the-u user_name option.
If you do not specify the -u user_name option, ansible-playbook connects to the managed
host as the user that is currently logged in to the control node.
/usr/share/ansible/roles/rhel-system-roles.network/README.md
ansible-playbook(1) man page
5.2. CONFIGURING A DYNAMIC ETHERNET CONNECTION USING

RHEL SYSTEM ROLES WITH THE INTERFACE NAME
This procedure describes how to use RHEL System Roles to remotely add a dynamic Ethernet
connection for the enp7s0 interface by running an Ansible playbook. With this setting, the network
connection requests the IP settings for this connection from a DHCP server. Run this procedure on
the Ansible control node.
Prerequisites
A DHCP server is available in the network.
22
The host uses NetworkManager to configure the network.
Procedure
node.example.com
2. Create the ~/ethernet-dynamic-IP.yml playbook with the following content:
---
- name: Configure an Ethernet connection with dynamic IP
become: true
tasks:
- include_role:
vars:
- name: enp7s0
type: ethernet
autoconnect: yes
ip:
dhcp4: yes
auto6: yes
state: up
# ansible-playbook -u root ~/ethernet-dynamic-IP.yml
# ansible-playbook -u user_name --ask-become-pass ~/ethernet-dynamic-IP.yml

/usr/share/ansible/roles/rhel-system-roles.network/README.md file
23
5.3. CONFIGURING VLAN TAGGING USING SYSTEM ROLES

You can use the networking RHEL System Role to configure VLAN tagging. This procedure
describes how to add an Ethernet connection and a VLAN with ID 10 on top of this Ethernet
connection. As the child device, the VLAN connection contains the IP, default gateway, and DNS
configurations.
Depending on your environment, adjust the play accordingly. For example:
To use the VLAN as a port in other connections, such as a bond, omit the ip attribute, and
set the IP configuration in the child configuration.
To use team, bridge, or bond devices in the VLAN, adapt the interface_name and type
attributes of the ports you use in the VLAN.
Prerequisites
Procedure
node.example.com
2. Create the ~/vlan-ethernet.yml playbook with the following content:
---
- name: Configure a VLAN that uses an Ethernet connection
become: true
tasks:
- include_role:
vars:
# Add an Ethernet profile for the underlying device of the VLAN
- name: enp1s0
type: ethernet
autoconnect: yes
state: up
ip:
dhcp4: no
auto6: no
# Define the VLAN profile

- name: enp1s0.10
type: vlan
ip:
24
address:
- "192.0.2.1/24"
- "2001:db8:1::1/64"
gateway4: 192.0.2.254
dns:
- 192.0.2.200
- 2001:db8:1::ffbb
dns_search:
- example.com
vlan_id: 10
parent: enp1s0
state: up
The parent attribute in the VLAN profile configures the VLAN to operate on top of the
enp1s0 device.
# ansible-playbook -u root ~/vlan-ethernet.yml
# ansible-playbook -u user_name --ask-become-pass ~/vlan-ethernet.yml

5.4. CONFIGURING A NETWORK BRIDGE USING RHEL SYSTEM ROLES

You can use the networking RHEL System Role to configure a Linux bridge. This procedure
describes how to configure a network bridge that uses two Ethernet devices, and sets IPv4 and
IPv6 addresses, default gateways, and DNS configuration.
NOTE
Set the IP configuration on the bridge and not on the ports of the Linux bridge.
Prerequisites
25
Two or more physical or virtual network devices are installed on the server.
Procedure
node.example.com
2. Create the ~/bridge-ethernet.yml playbook with the following content:
---
- name: Configure a network bridge that uses two Ethernet ports
become: true
tasks:
- include_role:
vars:
# Define the bridge profile
- name: bridge0
type: bridge
interface_name: bridge0
ip:
address:
- "192.0.2.1/24"
- "2001:db8:1::1/64"
gateway4: 192.0.2.254
dns:
- 192.0.2.200
- 2001:db8:1::ffbb
dns_search:
- example.com
state: up
# Add an Ethernet profile to the bridge

- name: bridge0-port1
type: ethernet
controller: bridge0
port_type: bridge
state: up
# Add a second Ethernet profile to the bridge

- name: bridge0-port2
type: ethernet
controller: bridge0
port_type: bridge
state: up
26
# ansible-playbook -u root ~/bridge-ethernet.yml
# ansible-playbook -u user_name --ask-become-pass ~/bridge-ethernet.yml

5.5. CONFIGURING A NETWORK BOND USING RHEL SYSTEM ROLES

You can use the network RHEL System Role to configure a network bond. This procedure describes
how to configure a bond in active-backup mode that uses two Ethernet devices, and sets an IPv4
and IPv6 addresses, default gateways, and DNS configuration.
NOTE
Set the IP configuration on the bond and not on the ports of the Linux bond.
Prerequisites
Two or more physical or virtual network devices are installed on the server.
Procedure
node.example.com
2. Create the ~/bond-ethernet.yml playbook with the following content:
---
- name: Configure a network bond that uses two Ethernet ports
27
become: true
tasks:
- include_role:
vars:
# Define the bond profile
- name: bond0
type: bond
interface_name: bond0
ip:
address:
- "192.0.2.1/24"
- "2001:db8:1::1/64"
gateway4: 192.0.2.254
dns:
- 192.0.2.200
- 2001:db8:1::ffbb
dns_search:
- example.com
bond:
mode: active-backup
state: up
# Add an Ethernet profile to the bond

- name: bond0-port1
type: ethernet
controller: bond0
state: up
# Add a second Ethernet profile to the bond

- name: bond0-port2
type: ethernet
controller: bond0
state: up
# ansible-playbook -u root ~/bond-ethernet.yml
# ansible-playbook -u user_name --ask-become-pass ~/bond-ethernet.yml

28
5.6. CONFIGURING A STATIC ETHERNET CONNECTION WITH 802.1X

NETWORK AUTHENTICATION USING RHEL SYSTEM ROLES
Using the RHEL networking System Role, you can automate the creation of an Ethernet connection
that uses the 802.1X standard to authenticate the client. This procedure describes how to remotely
add an Ethernet connection for the enp1s0 interface with the following settings by running an
Ansible playbook:
802.1X network authentication using the TLS Extensible Authentication Protocol (EAP)
Run this procedure on the Ansible control node.
Prerequisites
If you use a different remote user than root when you run the playbook, you must have
The network supports 802.1X network authentication.
The managed node uses NetworkManager.
The following files required for TLS authentication exist on the control node:
The client key is stored in the /srv/data/client.key file.
The client certificate is stored in the /srv/data/client.crt file.
The Certificate Authority (CA) certificate is stored in the /srv/data/ca.crt file.
Procedure
29
node.example.com
2. Create the ~/enable-802.1x.yml playbook with the following content:
---
- name: Configure an Ethernet connection with 802.1X authentication
become: true
tasks:
- name: Copy client key for 802.1X authentication
copy:
src: "/srv/data/client.key"
dest: "/etc/pki/tls/private/client.key"
mode: 0600
- name: Copy client certificate for 802.1X authentication

copy:
src: "/srv/data/client.crt"
dest: "/etc/pki/tls/certs/client.crt"
- name: Copy CA certificate for 802.1X authentication

copy:
src: "/srv/data/ca.crt"
dest: "/etc/pki/ca-trust/source/anchors/ca.crt"
- include_role:
vars:
- name: enp1s0
type: ethernet
autoconnect: yes
ip:
address:
- 192.0.2.1/24
- 2001:db8:1::1/64
gateway4: 192.0.2.254
dns:
- 192.0.2.200
- 2001:db8:1::ffbb
dns_search:
- example.com
ieee802_1x:
identity: user_name
eap: tls
private_key: "/etc/pki/tls/private/client.key"
private_key_password: "password"
client_cert: "/etc/pki/tls/certs/client.crt"
ca_cert: "/etc/pki/ca-trust/source/anchors/ca.crt"
domain_suffix_match: example.com
state: up
30
# ansible-playbook -u root ~/enable-802.1x.yml
# ansible-playbook -u user_name --ask-become-pass ~/ethernet-static-IP.yml

5.7. SETTING THE DEFAULT GATEWAY ON AN EXISTING

CONNECTION USING SYSTEM ROLES
You can use the networking RHEL System Role to set the default gateway.
IMPORTANT
When you run a play that uses the networking RHEL System Role, the System Role
overrides an existing connection profile with the same name if the value of settings
does not match the ones specified in the play. Therefore, always specify the whole
configuration of the network connection profile in the play, even if, for example, the
IP configuration already exists. Otherwise, the role resets these values to their
defaults.
Depending on whether it already exists, the procedure creates or updates the enp1s0 connection
profile with the following settings:
Prerequisites
31
Procedure
node.example.com
2. Create the ~/ethernet-connection.yml playbook with the following content:
---
- name: Configure an Ethernet connection with static IP and default gateway
become: true
tasks:
- include_role:
vars:
- name: enp1s0
type: ethernet
autoconnect: yes
ip:
address:
- 198.51.100.20/24
- 2001:db8:1::1/64
gateway4: 198.51.100.254
dns:
- 198.51.100.200
- 2001:db8:1::ffbb
dns_search:
- example.com
state: up
# ansible-playbook -u root ~/ethernet-connection.yml
# ansible-playbook -u user_name --ask-become-pass ~/ethernet-connection.yml

32
5.8. CONFIGURING A STATIC ROUTE USING RHEL SYSTEM ROLES

You can use the networking RHEL System Role to configure static routes.
IMPORTANT
configuration of the network connection profile in the play, even if, for example, the
IP configuration already exists. Otherwise, the role resets these values to their
defaults.
Static routes:
192.0.2.0/24 with gateway 198.51.100.1
203.0.113.0/24 with gateway 198.51.100.2
Prerequisites
Procedure
node.example.com
33
2. Create the ~/add-static-routes.yml playbook with the following content:
---
- name: Configure an Ethernet connection with static IP and additional routes
become: true
tasks:
- include_role:
vars:
- name: enp7s0
type: ethernet
autoconnect: yes
ip:
address:
- 198.51.100.20/24
- 2001:db8:1::1/64
gateway4: 198.51.100.254
dns:
- 198.51.100.200
- 2001:db8:1::ffbb
dns_search:
- example.com
route:
- network: 192.0.2.0
prefix: 24
gateway: 198.51.100.1
- network: 203.0.113.0
prefix: 24
gateway: 198.51.100.2
state: up
# ansible-playbook -u root ~/add-static-routes.yml
# ansible-playbook -u user_name --ask-become-pass ~/add-static-routes.yml

Verification steps
Display the routing table:
34
# ip -4 route
default via 198.51.100.254 dev enp7s0 proto static metric 100
192.0.2.0/24 via 198.51.100.1 dev enp7s0 proto static metric 100
203.0.113.0/24 via 198.51.100.2 dev enp7s0 proto static metric 100
...
5.9. USING SYSTEM ROLES TO SET ETHTOOL FEATURES

You can use the networking RHEL System Role to configure ethtool features of a NetworkManager
connection.
IMPORTANT
configuration of the network connection profile in the play, even if, for example the
IP configuration, already exists. Otherwise the role resets these values to their
defaults.
ethtool features:
Generic receive offload (GRO): disabled
Generic segmentation offload (GSO): enabled
TX stream control transmission protocol (SCTP) segmentation: disabled
Prerequisites
35
Procedure
node.example.com
2. Create the ~/configure-ethernet-device-with-ethtool-features.yml playbook with the

following content:
---
- name: Configure an Ethernet connection with ethtool features
become: true
tasks:
- include_role:
vars:
- name: enp1s0
type: ethernet
autoconnect: yes
ip:
address:
- 198.51.100.20/24
- 2001:db8:1::1/64
gateway4: 198.51.100.254
dns:
- 198.51.100.200
- 2001:db8:1::ffbb
dns_search:
- example.com
ethtool:
features:
gro: "no"
gso: "yes"
tx_sctp_segmentation: "no"
state: up
# ansible-playbook -u root ~/configure-ethernet-device-with-ethtool-features.yml
# ansible-playbook -u user_name --ask-become-pass ~/configure-ethernet-device-

with-ethtool-features.yml
36

5.10. USING SYSTEM ROLES TO CONFIGURE ETHTOOL COALESCE

SETTINGS
You can use the networking RHEL System Role to configure ethtool coalesce settings of a
NetworkManager connection.
IMPORTANT
configuration of the network connection profile in the play, even if, for example the
IP configuration, already exists. Otherwise the role resets these values to their
defaults.
ethtool coalesce settings:
RX frames: 128
TX frames: 128
Prerequisites
37
Procedure
node.example.com
2. Create the ~/configure-ethernet-device-with-ethtoolcoalesce-settings.yml playbook with

the following content:
---
- name: Configure an Ethernet connection with ethtool coalesce settings
become: true
tasks:
- include_role:
vars:
- name: enp1s0
type: ethernet
autoconnect: yes
ip:
address:
- 198.51.100.20/24
- 2001:db8:1::1/64
gateway4: 198.51.100.254
dns:
- 198.51.100.200
- 2001:db8:1::ffbb
dns_search:
- example.com
ethtool:
coalesce:
rx_frames: 128
tx_frames: 128
state: up
# ansible-playbook -u root ~/configure-ethernet-device-with-ethtoolcoalesce-

settings.yml
# ansible-playbook -u user_name --ask-become-pass ~/configure-ethernet-device-

with-ethtoolcoalesce-settings.yml
38

39
CHAPTER 6. POSTFIX ROLE VARIABLES IN SYSTEM ROLES

The postfix role variables allow the user to install, configure, and start the Postfix Mail Transfer
Agent (MTA).
The following role variables are defined in this section:
postfix_conf: It includes key/value pairs of all the supported Postfix configuration

parameters. By default, the postfix_conf does not have a value.
For example: `postfix_conf`:

relayhost: "example.com"
postfix_check: It determines if a check has been executed before starting the Postfix to
verify the configuration changes. The default value is true.
For example: `postfix_check: true`
postfix_backup: It determines if a single backup copy of the configuration is created. By

default the postfix_backup value is false.
To overwrite any previous backup run the following command:
cp /etc/postfix/main.cf /etc/postfix/main.cf.backup
If the postfix_backup value is changed totrue, you must also set the postfix_backup_multiple
value to false.
For example: postfix_backup: true

postfix_backup_multiple: false
postfix_backup_multiple: It determines if the role will make a timestamped backup copy of

the configuration.
To keep multiple backup copies, run the following command:
cp /etc/postfix/main.cf /etc/postfix/main.cf.$(date -Isec)
By default the value of postfix_backup_multiple is true. The postfix_backup_multiple:true setting

overrides postfix_backup. If you want to use postfix_backup you must set the
postfix_backup_multiple:false.
IMPORTANT
The configuration parameters cannot be removed. Before running the Postfix role,
set the postfix_conf to all the required configuration parameters and use the file
module to remove /etc/postfix/main.cf

/usr/share/doc/rhel-system-roles/postfix/README.md
40
CHAPTER 7. CONFIGURING SELINUX USING SYSTEM ROLES
7.1. INTRODUCTION TO THE SELINUX SYSTEM ROLE

RHEL System Roles is a collection of Ansible roles and modules that provide a consistent
configuration interface to remotely manage multiple RHEL systems. The SELinux System Role
enables the following actions:
Cleaning local policy modifications related to SELinux booleans, file contexts, ports, and
logins.
Setting SELinux policy booleans, file contexts, ports, and logins.
Restoring file contexts on specified files or directories.
Managing SELinux modules.
The following table provides an overview of input variables available in the SELinux system role.
Table 7.1. SELinux system role variables
Role variable Description CLI alternative
selinux_policy Chooses a policy protecting SELINUXTYPE in

targeted processes or Multi Level /etc/selinux/config
Security protection.
selinux_state Switches SELinux modes. See setenforce and SELINUX in

ansible-doc selinux /etc/selinux/config.
selinux_booleans Enables and disables SELinux setsebool

booleans. See ansible-doc
seboolean.
selinux_fcontexts Adds or removes a SELinux file semanage fcontext

context mapping. See ansible-
doc sefcontext .
selinux_restore_dirs Restores SELinux labels in the restorecon -R

file-system tree.
selinux_ports Sets SELinux labels on ports. See semanage port

ansible-doc seport .
selinux_logins Sets users to SELinux user semanage login

mapping. See ansible-doc
selogin.
selinux_modules Installs, enables, disables, or semodule

removes SELinux modules.
The /usr/share/doc/rhel-system-roles/selinux/example-selinux-playbook.yml example playbook

41
The /usr/share/doc/rhel-system-roles/selinux/example-selinux-playbook.yml example playbook

installed by the rhel-system-roles package demonstrates how to set the targeted policy in
enforcing mode. The playbook also applies several local policy modifications and restores file
contexts in the /tmp/test_dir/ directory.
For a detailed reference on SELinux role variables, install the rhel-system-roles package, and see
the README.md or README.html files in the /usr/share/doc/rhel-system-roles/selinux/ directory.
Introduction to RHEL System Roles.
7.2. USING THE SELINUX SYSTEM ROLE TO APPLY SELINUX

SETTINGS ON MULTIPLE SYSTEMS
Follow the steps to prepare and apply an Ansible playbook with your verified SELinux settings.
Prerequisites
Access and permissions to one or more managed nodes, which are systems you want to
configure with the SELinux System Role.
Access and permissions to a control node, which is a system from which Red Hat Ansible
Engine configures other systems.
On the control node:
Red Hat Ansible Engine is installed.
The rhel-system-roles package is installed.
An inventory file which lists the managed nodes.
Procedure
1. Prepare your playbook. You can either start from the scratch or modify the example
playbook installed as a part of the rhel-system-roles package:
# cp /usr/share/doc/rhel-system-roles/selinux/example-selinux-playbook.yml my-selinux-
playbook.yml
# vi my-selinux-playbook.yml
2. Change the content of the playbook to fit your scenario. For example, the following part
ensures that the system installs and enables the selinux-local-1.pp SELinux module:
selinux_modules:
- { path: "selinux-local-1.pp", priority: "400" }
3. Save the changes, and exit the text editor.
4. Run your playbook on the host1, host2, and host3 systems:
# ansible-playbook -i host1,host2,host3 my-selinux-playbook.yml
42
For more information, install the rhel-system-roles package, and see the
/usr/share/doc/rhel-system-roles/selinux/ and /usr/share/ansible/roles/rhel-system-
roles.selinux/ directories.
How do I download and install Red Hat Ansible Engine
43
CHAPTER 8. USING THE LOGGING SYSTEM ROLE

As a system administrator, you can use the Logging System Role to configure a RHEL host as a
logging server to collect logs from many client systems.
8.1. THE LOGGING SYSTEM ROLE

With the Logging System Role, you can deploy logging configurations on local and remote hosts.
To apply a Logging System Role on one or more systems, you define the logging configuration in a
playbook. A playbook is a list of one or more plays. Playbooks are human-readable, and they are
written in the YAML format. For more information about playbooks, see Working with playbooks in
Ansible documentation.
The set of systems that you want to configure according to the playbook is defined in an inventory
file. For more information on creating and using inventories, seeHow to build your inventoryin
Ansible documentation.
Logging solutions provide multiple ways of reading logs and multiple logging outputs.
For example, a logging system can receive the following inputs:
local files,
systemd/journal,
another logging system over the network.
In addition, a logging system can have the following outputs:
logs stored in the local files in the /var/log directory,
logs sent to Elasticsearch,
logs forwarded to another logging system.
With the logging system role, you can combine the inputs and outputs to fit your scenario. For
example, you can configure a logging solution that stores inputs from journal in a local file, whereas
inputs read from files are both forwarded to another logging system and stored in the local log files.
8.2. LOGGING SYSTEM ROLE PARAMETERS

In a Logging System Role playbook, you define the inputs in the logging_inputs parameter, outputs
in the logging_outputs parameter, and the relationships between the inputs and outputs in the
logging_flows parameter. The Logging System Role processes these variables with additional
options to configure the logging system. You can also enable encryption.
NOTE
Currently, the only available logging system in the Logging System Role is Rsyslog.
logging_inputs: List of inputs for the logging solution.
name: Unique name of the input. Used in thelogging_flows: inputs list and a part of
the generated config file name.
44
type: Type of the input element. The type specifies a task type which corresponds to a
directory name in roles/rsyslog/{tasks,vars}/inputs/.
basics: Inputs configuring inputs fromsystemd journal or unix socket.
kernel_message: Load imklog if set totrue. Default to false.
use_imuxsock: Use imuxsock instead of imjournal. Default to false.
ratelimit_burst: Maximum number of messages that can be emitted within

ratelimit_interval. Default to 20000 if use_imuxsock is false. Default to 200 if
use_imuxsock is true.
ratelimit_interval: Interval to evaluateratelimit_burst. Default to 600 seconds if

use_imuxsock is false. Default to 0 ifuse_imuxsock is true. 0 indicates rate
limiting is turned off.
persist_state_interval: Journal state is persisted everyvalue messages. Default

to 10. Effective only when use_imuxsock is false.
files: Inputs configuring inputs from local files.
remote: Inputs configuring inputs from the other logging system over network.
state: State of the configuration file.present or absent. Default to present.
logging_outputs: List of outputs for the logging solution.
files: Outputs configuring outputs to local files.
forwards: Outputs configuring outputs to another logging system.
remote_files: Outputs configuring outputs from another logging system to local files.
logging_flows: List of flows that define relationships betweenlogging_inputs and

logging_outputs. The logging_flows variable has the following keys:
name: Unique name of the flow
inputs: List of logging_inputs name values
outputs: List of logging_outputs name values.
Documentation installed with the rhel-system-roles package in

/usr/share/ansible/roles/rhel-system-roles.logging/README.html
8.3. APPLYING A LOCAL LOGGING SYSTEM ROLE

Follow these steps to prepare and apply a Red Hat Ansible Engine playbook to configure a logging
solution on a set of separate machines. Each machine will record logs locally.
Prerequisites
configure with the Logging System Role.
45
NOTE
You do not have to have the rsyslog package installed, because the system role
installs rsyslog when deployed.
Procedure
b. Insert the following content:
---
- name: Deploying basics input and implicit files output
hosts: all
roles:
- rhel-system-roles.logging
vars:
logging_inputs:
- name: system_input
type: basics
logging_outputs:
- name: files_output
type: files
logging_flows:
- name: flow1
inputs: [system_input]
outputs: [files_output]
2. Run the playbook on a specific inventory:
# ansible-playbook -i inventory-file /path/to/file/logging-playbook.yml
Where: * inventory-file is the inventory file. *logging-playbook.yml is the playbook you use.
Verification
# rsyslogd -N 1
46
/etc/rsyslog.conf
2. Verify that the system sends messages to the log:
# logger test
b. View the /var/log/messages log, for example:
Aug 5 13:48:31 hostname root[6778]: test
Where `hostname` is the host name of the client system. Note that the log contains the
user name of the user that entered the logger command, in this case root.
8.4. FILTERING LOGS IN A LOCAL LOGGING SYSTEM ROLE

You can deploy a logging solution which filters the logs based on the rsyslog property-based filter.
Prerequisites
Red Hat Ansible Engine is installed
The rhel-system-roles package is installed
NOTE
Procedure
1. Create a new playbook.yml file with the following content:
---
- name: Deploying files input and configured files output
hosts: all
roles:
vars:
logging_inputs:
- name: files_input0
type: files
47
input_log_path: /var/log/containerA/*.log
- name: files_input1
type: files
input_log_path: /var/log/containerB/*.log
logging_outputs:
- name: files_output0
type: files
property: msg
property_op: contains
property_value: error
path: /var/log/errors.log
- name: files_output1
type: files
property: msg
property_op: "!contains"
property_value: error
path: /var/log/others.log
logging_flows:
- name: flow0
inputs: [files_input0, files_input1]
outputs: [files_output0, files_output1]
Using this configuration, all messages that contain the error string are logged in
/var/log/errors.log, and all other messages are logged in/var/log/others.log.
You can replace the error property value with the string by which you want to filter.
You can modify the variables according to your preferences.
2. Optional: Verify playbook syntax.
# ansible-playbook --syntax-check playbook.yml
3. Run the playbook on your inventory file:
# ansible-playbook -i inventory_file /path/to/file/playbook.yml
Verification
# rsyslogd -N 1
/etc/rsyslog.conf
2. Verify that the system sends messages that contain the error string to the log:
# logger error
b. View the /var/log/errors.log log, for example:
48
# cat /var/log/errors.log
Aug 5 13:48:31 hostname root[6778]: error
Where hostname is the host name of the client system. Note that the log contains the
user name of the user that entered the logger command, in this case root.

8.5. APPLYING A REMOTE LOGGING SOLUTION USING THE

LOGGING SYSTEM ROLE
Follow these steps to prepare and apply a Red Hat Ansible Engine playbook to configure a remote
logging solution. In this playbook, one or more clients take logs from systemd-journal and forward
them to a remote server. The server receives remote input from remote_rsyslog and remote_files
and outputs the logs to local files in directories named by remote host names.
Prerequisites
NOTE
Procedure
---
- name: Deploying remote input and remote_files output
hosts: server
roles:
49
vars:
logging_inputs:
- name: remote_udp_input
type: remote
udp_ports: [ 601 ]
- name: remote_tcp_input
type: remote
tcp_ports: [ 601 ]
logging_outputs:
- name: remote_files_output
type: remote_files
logging_flows:
- name: flow_0
inputs: [remote_udp_input, remote_tcp_input]
outputs: [remote_files_output]
- name: Deploying basics input and forwards output

hosts: clients
roles:
vars:
logging_inputs:
- name: basic_input
type: basics
logging_outputs:
- name: forward_output0
type: forwards
severity: info
target: _host1.example.com_
udp_port: 601
- name: forward_output1
type: forwards
facility: mail
target: _host1.example.com_
tcp_port: 601
logging_flows:
- name: flows0
inputs: [basic_input]
outputs: [forward_output0, forward_output1]
[basic_input]
[forward_output0, forward_output1]
Where host1.example.com is the logging server.
NOTE
You can modify the parameters in the playbook to fit your needs.
50

WARNING
The logging solution works only with the ports defined in the
SELinux policy of the server or client system and open in the
firewall. The default SELinux policy includes ports 601, 514, 6514,
10514, and 20514. To use a different port, modify the SELinux policy
on the client and server systems. Configuring the firewall through
system roles is not yet supported.
2. Create an inventory file that lists your servers and clients:
a. Create a new file and open it in a text editor, for example:
# vi inventory.ini
b. Insert the following content into the inventory file:
[servers]
server ansible_host=host1.example.com
[clients]
client ansible_host=host2.example.com
Where:
host1.example.com is the logging server.
host2.example.com is the logging client.
3. Run the playbook on your inventory.
# ansible-playbook -i /path/to/file/inventory.ini /path/to/file/_logging-playbook.yml
Where:
inventory.ini is the inventory file.
logging-playbook.yml is the playbook you created.
Verification
1. On both the client and the server system, test the syntax of the /etc/rsyslog.conf file:
# rsyslogd -N 1
/etc/rsyslog.conf
2. Verify that the client system sends messages to the server:
a. On the client system, send a test message:
51
# logger test
b. On the server system, view the /var/log/messages log, for example:
Aug 5 13:48:31 host2.example.com root[6778]: test
Where host2.example.com is the host name of the client system. Note that the log
contains the user name of the user that entered the logger command, in this case root.

RHEL System Roles KB article


/usr/share/ansible/roles/rhel-system-roles.logging/README.html.
RHEL System Roles
ansible-playbook(1) man page.
52
CHAPTER 9. CONFIGURING SECURE COMMUNICATION WITH THE SSH SYSTEM ROLES
CHAPTER 9. CONFIGURING SECURE COMMUNICATION WITH

THE SSH SYSTEM ROLES
As an administrator, you can use the SSHD System Role to configure SSH servers and the SSH
System Role to configure SSH clients consistently on any number of RHEL systems at the same
time by using Red Hat Ansible Automation Platform.
9.1. SSHD SYSTEM ROLE VARIABLES

In an SSHD System Role playbook, you can define the parameters for the SSH configuration file
according to your preferences and limitations.
If you do not configure these variables, the system role produces an sshd_config file that matches
the RHEL defaults.
In all cases, Booleans correctly render as yes and no in sshd configuration. You can define multi-
line configuration items using lists. For example:
sshd_ListenAddress:
- 0.0.0.0
- '::'
renders as:
ListenAddress 0.0.0.0
ListenAddress ::
Variables for the SSHD System Role
sshd_enable
If set to False, the role is completely disabled. Defaults toTrue.
sshd_skip_defaults
If set to True, the system role does not apply default values. Instead, you specify the complete
set of configuration defaults by using either the sshd dict, or sshd_Key variables. Defaults to
False.
sshd_manage_service
If set to False, the service is not managed, which means it is not enabled on boot and does not
start or reload. Defaults to True except when running inside a container or AIX, because the
Ansible service module does not currently support enabled for AIX.
sshd_allow_reload
If set to False, sshd does not reload after a change of configuration. This can help with
troubleshooting. To apply the changed configuration, reload sshd manually. Defaults to the
same value as sshd_manage_service except on AIX, wheresshd_manage_service defaults to
False but sshd_allow_reload defaults to True.
sshd_install_service
If set to True, the role installs service files for thesshd service. This overrides files provided in
the operating system. Do not set to True unless you are configuring a second instance and you
also change the sshd_service variable. Defaults to False.
The role uses the files pointed by the following variables as templates:
53
sshd_service_template_service (default: templates/sshd.service.j2)

sshd_service_template_at_service (default: templates/sshd@.service.j2)
sshd_service_template_socket (default: templates/sshd.socket.j2)
sshd_service
This variable changes the sshd service name, which is useful for configuring a secondsshd
service instance.
sshd
A dict that contains configuration. For example:
sshd:
Compression: yes
ListenAddress:
- 0.0.0.0
sshd_OptionName
You can define options by using simple variables consisting of the sshd_ prefix and the option
name instead of a dict. The simple variables override values in the sshd dict.. For example:
sshd_Compression: no
sshd_match and sshd_match_1 to sshd_match_9

A list of dicts or just a dict for a Match section. Note that these variables do not override match
blocks as defined in the sshd dict. All of the sources will be reflected in the resulting
configuration file.
Secondary variables for the SSHD System Role

You can use these variables to override the defaults that correspond to each supported platform.
sshd_packages
You can override the default list of installed packages using this variable.
sshd_config_owner, sshd_config_group, and sshd_config_mode
You can set the ownership and permissions for the openssh configuration file that this role
produces using these variables.
sshd_config_file
The path where this role saves the openssh server configuration produced.
sshd_config_namespace
The default value of this variable is null, which means that the role defines the entire content of
the configuration file including system defaults. Alternatively, you can use this variable to invoke
this role from other roles or from multiple places in a single playbook on systems that do not
support drop-in directory. The sshd_skip_defaults variable is ignored and no system defaults
are used in this case.
When this variable is set, the role places the configuration that you specify to configuration
snippets in an existing configuration file under the given namespace. If your scenario requires
applying the role several times, you need to select a different namespace for each application.
NOTE
54
NOTE
Limitations of the openssh configuration file still apply. For example, only the first
option specified in a configuration file is effective for most of the configuration
options.
Technically, the role places snippets in "Match all" blocks, unless they contain other match
blocks, to ensure they are applied regardless of the previous match blocks in the existing
configuration file. This allows configuring any non-conflicting options from different roles
invocations.
sshd_binary
The path to the sshd executable of openssh.
sshd_service
The name of the sshd service. By default, this variable contains the name of thesshd service
that the target platform uses. You can also use it to set the name of the custom sshd service
when the role uses the sshd_install_service variable.
sshd_verify_hostkeys
Defaults to auto. When set to auto, this lists all host keys that are present in the produced
configuration file, and generates any paths that are not present. Additionally, permissions and
file owners are set to default values. This is useful if the role is used in the deployment stage to
make sure the service is able to start on the first attempt. To disable this check, set this variable
to an empty list [].
sshd_hostkey_owner, sshd_hostkey_group, sshd_hostkey_mode
Use these variables to set the ownership and permissions for the host keys from
sshd_verify_hostkeys.
sshd_sysconfig
On RHEL-based systems, this variable configures additional details of the sshd service. If set to
true, this role manages also the/etc/sysconfig/sshd configuration file based on the following
configuration. Defaults to false.
sshd_sysconfig_override_crypto_policy
In RHEL, when set to true, this variable overrides the system-wide crypto policy. Defaults to
false.
sshd_sysconfig_use_strong_rng
On RHEL-based systems, this variable can force sshd to reseed theopenssl random number
generator with the number of bytes given as the argument. The default is 0, which disables this
functionality. Do not turn this on if the system does not have a hardware random number
generator.
9.2. CONFIGURING OPENSSH SERVERS USING THE SSHD SYSTEM

ROLE
You can use the SSHD System Role to configure multiple SSH servers by running an Ansible
playbook.
Prerequisites
configure with the SSHD System Role.
55
Procedure
1. Copy the example playbook for the SSHD System Role:
# cp /usr/share/doc/rhel-system-roles/sshd/example-root-login-playbook.yml path/custom-
playbook.yml
2. Open the copied playbook by using a text editor, for example:
# vim path/custom-playbook.yml
---
- hosts: all
tasks:
- name: Configure sshd to prevent root and password login except from particular subnet
include_role:
name: rhel-system-roles.sshd
vars:
sshd:
# root login and password login is enabled only from a particular subnet
PermitRootLogin: no
PasswordAuthentication: no
Match:
- Condition: "Address 192.0.2.0/24"
PermitRootLogin: yes
PasswordAuthentication: yes
The playbook configures the managed node as an SSH server configured so that:
password and root user login is disabled
password and root user login is enabled only from the subnet192.0.2.0/24
You can modify the variables according to your preferences. For more details, see SSHD
Server System Role variables .
# ansible-playbook --syntax-check path/custom-playbook.yml
# ansible-playbook -i inventory_file path/custom-playbook.yml
...
56
PLAY RECAP
**************************************************
localhost : ok=12 changed=2 unreachable=0 failed=0

skipped=10 rescued=0 ignored=0
Verification
1. Log in to the SSH server:
$ ssh user1@10.1.1.1
Where:
user1 is a user on the SSH server.
10.1.1.1 is the IP address of the SSH server.
2. Check the contents of the sshd_config file on the SSH server:
$ vim /etc/ssh/sshd_config
# Ansible managed
HostKey /etc/ssh/ssh_host_rsa_key
HostKey /etc/ssh/ssh_host_ecdsa_key
HostKey /etc/ssh/ssh_host_ed25519_key
AcceptEnv LANG LC_CTYPE LC_NUMERIC LC_TIME LC_COLLATE LC_MONETARY
LC_MESSAGES
AcceptEnv LC_PAPER LC_NAME LC_ADDRESS LC_TELEPHONE LC_MEASUREMENT
AcceptEnv LC_IDENTIFICATION LC_ALL LANGUAGE
AcceptEnv XMODIFIERS
AuthorizedKeysFile .ssh/authorized_keys
ChallengeResponseAuthentication no
GSSAPIAuthentication yes
GSSAPICleanupCredentials no
PasswordAuthentication no
PermitRootLogin no
PrintMotd no
Subsystem sftp /usr/libexec/openssh/sftp-server
SyslogFacility AUTHPRIV
UsePAM yes
X11Forwarding yes
Match Address 192.0.2.0/24
PasswordAuthentication yes
PermitRootLogin yes
3. Check that you can connect to the server as root from the 192.0.2.0/24 subnet:
a. Determine your IP address:
$ hostname -I
192.0.2.1
If the IP address is within the 192.0.2.1 - 192.0.2.254 range, you can connect to the
57
If the IP address is within the 192.0.2.1 - 192.0.2.254 range, you can connect to the
server.
b. Connect to the server as root:
$ ssh root@10.1.1.1
/usr/share/doc/rhel-system-roles/sshd/README.md file.
9.3. SSH SYSTEM ROLE VARIABLES

In an SSH System Role playbook, you can define the parameters for the client SSH configuration
file according to your preferences and limitations.
If you do not configure these variables, the system role produces a global ssh_config file that
matches the RHEL defaults.
In all cases, booleans correctly render as yes or no in ssh configuration. You can define multi-line
configuration items using lists. For example:
LocalForward:
- 22 localhost:2222
- 403 localhost:4003
renders as:
LocalForward 22 localhost:2222
LocalForward 403 localhost:4003
NOTE
The configuration options are case sensitive.
Variables for the SSH System Role
ssh_user
You can define an existing user name for which the system role modifies user-specific
configuration. The user-specific configuration is saved in ~/.ssh/config of the given user. The
default value is null, which modifies global configuration for all users.
ssh_skip_defaults
Defaults to auto. If set to auto, the system role writes the system-wide configuration file
/etc/ssh/ssh_config and keeps the RHEL defaults defined there. Creating a drop-in
configuration file, for example by defining the ssh_drop_in_name variable, automatically
disables the ssh_skip_defaults variable.
ssh_drop_in_name
Defines the name for the drop-in configuration file, which is placed in the system-wide drop-in
directory. The name is used in the template /etc/ssh/ssh_config.d/{ssh_drop_in_name}.conf to
reference the configuration file to be modified. If the system does not support drop-in directory,
58
the default value is null. If the system supports drop-in directories, the default value is 00-
ansible.

WARNING
If the system does not support drop-in directories, setting this option will
make the play fail.
The suggested format is NN-name, where NN is a two-digit number used for ordering the
configuration files and name is any descriptive name for the content or the owner of the file.
ssh
A dict that contains configuration options and their respective values.
ssh_OptionName
You can define options by using simple variables consisting of the ssh_ prefix and the option
name instead of a dict. The simple variables override values in the ssh dict.
ssh_additional_packages
This role automatically installs the openssh and openssh-clients packages, which are needed for
the most common use cases. If you need to install additional packages, for example, openssh-
keysign for host-based authentication, you can specify them in this variable.
ssh_config_file
The path to which the role saves the configuration file produced. Default value:
If the system has a drop-in directory, the default value is defined by the template
/etc/ssh/ssh_config.d/{ssh_drop_in_name}.conf.
If the system does not have a drop-in directory, the default value is /etc/ssh/ssh_config.
if the ssh_user variable is defined, the default value is~/.ssh/config.
ssh_config_owner, ssh_config_group, ssh_config_mode

The owner, group and modes of the created configuration file. By default, the owner of the file
is root:root, and the mode is0644. If ssh_user is defined, the mode is0600, and the owner and
group are derived from the user name specified in the ssh_user variable.
9.4. CONFIGURING OPENSSH CLIENTS USING THE SSH SYSTEM

ROLE
You can use the SSH System Role to configure multiple SSH clients by running an Ansible playbook.
Prerequisites
configure with the SSH System Role.
59
Procedure
---
- hosts: all
tasks:
- name: "Configure ssh clients"
include_role:
name: rhel-system-roles.ssh
vars:
ssh_user: root
ssh:
Compression: true
GSSAPIAuthentication: no
ControlMaster: auto
ControlPath: ~/.ssh/.cm%C
Host:
- Condition: example
Hostname: example.com
User: user1
ssh_ForwardX11: no
This playbook configures the root user’s SSH client preferences on the managed nodes with
the following configurations:
Compression is enabled.
ControlMaster multiplexing is set to auto.
The example alias for connecting to theexample.com host is user1.
The example host alias is created, which represents a connection to theexample.com

host the with user1 user name.
X11 forwarding is disabled.
Optionally, you can modify these variables according to your preferences. For more details,
see SSH Client Role variables .
# ansible-playbook --syntax-check path/custom-playbook.yml
# ansible-playbook -i inventory_file path/custom-playbook.yml
60
Verification
Verify that the managed node has the correct configuration by opening the SSH
configuration file in a text editor, for example:
# vi ~root/.ssh/config
After application of the example playbook shown above, the configuration file should have
the following content:
# Ansible managed
Compression yes
ControlMaster auto
ControlPath ~/.ssh/.cm%C
ForwardX11 no
GSSAPIAuthentication no
Host example
Hostname example.com
User user1
9.5. USING THE SSH SERVER SYSTEM ROLE FOR NON-EXCLUSIVE

CONFIGURATION
Normally, applying the SSHD System Role overwrites the entire configuration. This may be
problematic if you have previously adjusted the configuration, for example with a different system
role or playbook. To apply the SSHD System Role for only selected configuration options while
keeping other options in place, you can use the non-exclusive configuration.
In RHEL 8 and earlier, you can apply the non-exclusive configuration with a configuration snippet.
For more information, see Using the SSH Server System Role for non-exclusive configurationin
RHEL 8 documentation.
In RHEL 9, you can apply the non-exclusive configuration by using files in a drop-in directory. The
default configuration file is already placed in the drop-in directory as /etc/ssh/sshd_config.d/00-
ansible_system_role.conf.
Prerequisites
configure with the SSHD System Role.
The ansible-core package is installed.
A playbook for a different RHEL System Role. For additional information, see Applying
a role.
Procedure
61
1. Add a configuration snippet with the sshd_config_file variable to the playbook:
---
- hosts: all
tasks:
- name: <Configure sshd to accept some useful environment variables>
include_role:
name: rhel-system-roles.sshd
vars:
sshd_config_file: /etc/ssh/sshd_config.d/<42-my-application>.conf
sshd:
# Environment variables to accept
AcceptEnv:
LANG
LS_COLORS
EDITOR
In the sshd_config_file variable, define the .conf file into which the SSHD System Role
writes the configuration options.
Use a two-digit prefix, for example 42- to specify the order in which the configuration files
will be applied.
When you apply the playbook to the inventory, the role adds the following configuration
options to the file defined by the sshd_config_file variable.
# Ansible managed
#
AcceptEnv LANG LS_COLORS EDITOR
Verification
Optional: Verify playbook syntax.
# ansible-playbook --syntax-check playbook.yml -i inventory_file
/usr/share/doc/rhel-system-roles/sshd/README.md file.
62
CHAPTER 10. CONFIGURING VPN CONNECTIONS WITH IPSEC BY USING THE RHEL VPN SYSTEM ROLE
CHAPTER 10. CONFIGURING VPN CONNECTIONS WITH IPSEC

BY USING THE RHEL VPN SYSTEM ROLE
With the VPN System Role, you can configure VPN connections on RHEL systems by using Red Hat
Ansible Automation Platform. You can use it to set up host-to-host, network-to-network, VPN
Remote Access Server, and mesh configurations.
For host-to-host connections, the role sets up a VPN tunnel between each pair of hosts in the list
of vpn_connections using the default parameters, including generating keys as needed.
Alternatively, you can configure it to create an opportunistic mesh configuration between all hosts
listed. The role assumes that the names of the hosts under hosts are the same as the names of the
hosts used in the Ansible inventory, and that you can use those names to configure the tunnels.
NOTE
The VPN RHEL System Role currently supports only Libreswan, which is an IPsec
implementation, as the VPN provider.
10.1. CREATING A HOST-TO-HOST VPN WITH IPSEC USING THE VPN

SYSTEM ROLE
You can use the VPN System Role to configure host-to-host connections by running an Ansible
playbook on the control node, which will configure all the managed nodes listed in an inventory file.
Prerequisites
configure with the VPN System Role.
Core configures other systems.
The ansible-core and rhel-system-roles packages are installed.
Procedure
- name: Host to host VPN

hosts: managed_node1, managed_node2
roles:
- rhel-system-roles.vpn
vars:
vpn_connections:
- hosts:
managed_node1:
managed_node2:
This playbook configures the connection managed_node1-to-managed_node2 using pre-

shared key authentication with keys auto-generated by the system role.
63
2. Optional: Configure connections from managed hosts to external hosts that are not listed
in the inventory file by adding the following section to the vpn_connections list of hosts:
vpn_connections:
- hosts:
managed_node1:
managed_node2:
external_node:
hostname: 192.0.2.2
This configures two additional connections: managed_node1-to-external_node and

managed_node2-to-external_node.
NOTE
The connections are configured only on the managed nodes and not on the external
node.
1. Optional: You can specify multiple VPN connections for the managed nodes by using
additional sections within vpn_connections, for example a control plane and a data plane:
- name: Multiple VPN

hosts: managed_node1, managed_node2
roles:
vars:
vpn_connections:
- name: control_plane_vpn
hosts:
managed_node1:
hostname: 192.0.2.0 # IP for the control plane
managed_node2:
hostname: 192.0.2.1
- name: data_plane_vpn
hosts:
managed_node1:
hostname: 10.0.0.1 # IP for the data plane
managed_node2:
hostname: 10.0.0.2
2. Optional: You can modify the variables according to your preferences. For more details, see
the /usr/share/doc/rhel-system-roles/vpn/README.md file.
# ansible-playbook --syntax-check /path/to/file/playbook.yml -i /path/to/file/inventory_file
# ansible-playbook -i /path/to/file/inventory_file /path/to/file/playbook.yml
Verification
1. On the managed nodes, confirm that the connection is successfully loaded:
64
# ipsec status | grep connection.name
Replace connection.name with the name of the connection from this node, for example
managed_node1-to-managed_node2.
NOTE
By default, the role generates a descriptive name for each connection it creates from
the perspective of each system. For example, when creating a connection between
managed_node1 and managed_node2, the descriptive name of this connection on
managed_node1 is managed_node1-to-managed_node2 but on managed_node2 the
connection is named managed_node2-to-managed_node1.
1. On the managed nodes, confirm that the connection is successfully started:
# ipsec trafficstatus | grep connection.name
2. Optional: If a connection did not successfully load, manually add the connection by entering
the following command. This will provide more specific information indicating why the
connection failed to establish:
# ipsec auto --add connection.name
NOTE
Any errors that may have occurred during the process of loading and starting
the connection are reported in the logs, which can be found in
/var/log/pluto.log. Because these logs are hard to parse, try to manually add
the connection to obtain log messages from the standard output instead.
10.2. CREATING AN OPPORTUNISTIC MESH VPN CONNECTION WITH

IPSEC BY USING THE VPN SYSTEM ROLE
You can use the VPN System Role to configure an opportunistic mesh VPN connection that uses
certificates for authentication by running an Ansible playbook on the control node, which will
configure all the managed nodes listed in an inventory file.
Authentication with certificates is configured by defining the auth_method: cert parameter in the
playbook. The VPN System Role assumes that the IPsec Network Security Services (NSS) crypto
library, which is defined in the /etc/ipsec.d directory, contains the necessary certificates. By default,
the node name is used as the certificate nickname. In this example, this is managed_node1. You can
define different certificate names by using the cert_name attribute in your inventory.
In the following example procedure, the control node, which is the system from which you will run
the Ansible playbook, shares the same classless inter-domain routing (CIDR) number as both of the
managed nodes (192.0.2.0/24) and has the IP address 192.0.2.7. Therefore, the control node falls
under the private policy which is automatically created for CIDR 192.0.2.0/24.
To prevent SSH connection loss during the play, a clear policy for the control node is included in
the list of policies. Note that there is also an item in the policies list where the CIDR is equal to
default. This is because this playbook overrides the rule from the default policy to make it private
instead of private-or-clear.
65
Prerequisites
configure with the VPN System Role.
On all the managed nodes, the NSS database in the /etc/ipsec.d directory contains all
the certificates necessary for peer authentication. By default, the node name is used as
the certificate nickname.
Core configures other systems.
The ansible-core and rhel-system-roles packages are installed.
Procedure
- name: Mesh VPN

hosts: managed_node1, managed_node2, managed_node3
roles:
vars:
vpn_connections:
- opportunistic: true
auth_method: cert
policies:
- policy: private
cidr: default
- policy: private-or-clear
cidr: 198.51.100.0/24
- policy: private
cidr: 192.0.2.0/24
- policy: clear
cidr: 192.0.2.7/32
2. Optional: You can modify the variables according to your preferences. For more details, see
the /usr/share/doc/rhel-system-roles/vpn/README.md file.

For details about the parameters used in the VPN System Role and additional information
about the VPN System Role, see the /usr/share/doc/rhel-system-roles/vpn/README.md
file.
66
For details about the ansible-playbook command, see theansible-playbook(1) man page.
67
CHAPTER 11. SETTING A CUSTOM CRYPTOGRAPHIC POLICY

ACROSS SYSTEMS
As an administrator, you can use the Crypto Policies System Role on RHEL to quickly and
consistently configure custom cryptographic policies across many different systems using the
Ansible Core package.
11.1. CRYPTO POLICIES SYSTEM ROLE VARIABLES AND FACTS

In a Crypto Policies System Role playbook, you can define the parameters for the crypto policies
configuration file according to your preferences and limitations.
If you do not configure any variables, the system role does not configure the system and only
reports the facts.
Selected variables for the Crypto Policies System Role
crypto_policies_policy
Determines the cryptographic policy the system role applies to the managed nodes. For details
about the different crypto policies, see System-wide cryptographic policies .
crypto_policies_reload
If set to yes, the affected services, currently the ipsec, bind, and sshd services, reload after
applying a crypto policy. Defaults to yes.
crypto_policies_reboot_ok
If set to yes, and a reboot is necessary after the system role changes the crypto policy, it sets
crypto_policies_reboot_required to yes. Defaults to no.
Facts set by the Crypto Policies System Role
crypto_policies_active
Lists the currently selected policy.
crypto_policies_available_policies
Lists all available policies available on the system.
crypto_policies_available_subpolicies
Lists all available subpolicies available on the system.
Creating and setting a custom system-wide cryptographic policy.
11.2. SETTING A CUSTOM CRYPTOGRAPHIC POLICY USING THE

CRYPTO POLICIES SYSTEM ROLE
You can use the Crypto Policies System Role to configure a large number of managed nodes
consistently from a single control node.
Prerequisites
68
CHAPTER 11. SETTING A CUSTOM CRYPTOGRAPHIC POLICY ACROSS SYSTEMS
configure with the Crypto Policies System Role.
The Ansible Core package is installed on the control machine.
Procedure
---
- hosts: all
tasks:
- name: Configure crypto policies
include_role:
name: rhel-system-roles.crypto_policies
vars:
- crypto_policies_policy: FUTURE
- crypto_policies_reboot_ok: true
You can replace the FUTURE value with your preferred crypto policy, for example:
DEFAULT, LEGACY, and FIPS:OSPP.
The crypto_policies_reboot_ok: true variable causes the system to reboot after the system
role changes the crypto policy.
For more details, see Crypto Policies System Role variables and facts.
# ansible-playbook -i inventory_file playbook.yml
Verification
1. On the control node, create another playbook named, for example, verify_playbook.yml:
- hosts: all
tasks:
- name: Verify active crypto policy
include_role:
name: rhel-system-roles.crypto_policies
- debug:
var: crypto_policies_active
This playbook does not change any configurations on the system, only reports the active
policy on the managed nodes.
2. Run the playbook on the same inventory file:
# ansible-playbook -i inventory_file verify_playbook.yml
69
TASK [debug] **************************

ok: [host] => {
"crypto_policies_active": "FUTURE"
}
The "crypto_policies_active": variable shows the policy active on the managed node.

/usr/share/ansible/roles/rhel-system-roles.crypto_policies/README.md file.
Installing RHEL System Roles. .
Applying a system role .
70
CHAPTER 12. USING THE CLEVIS AND TANG SYSTEM ROLES
12.1. INTRODUCTION TO THE CLEVIS AND TANG SYSTEM ROLES

configuration interface to remotely manage multiple RHEL systems.
You can use Ansible roles for automated deployments of Policy-Based Decryption (PBD) solutions
using Clevis and Tang. The rhel-system-roles package contains these system roles, the related
examples, and also the reference documentation.
The nbde_client System Role enables you to deploy multiple Clevis clients in an automated way.
Note that the nbde_client role supports only Tang bindings, and you cannot use it for TPM2
bindings at the moment.
The nbde_client role requires volumes that are already encrypted using LUKS. This role supports to
bind a LUKS-encrypted volume to one or more Network-Bound (NBDE) servers - Tang servers.
You can either preserve the existing volume encryption with a passphrase or remove it. After
removing the passphrase, you can unlock the volume only using NBDE. This is useful when a volume
is initially encrypted using a temporary key or password that you should remove after the system
you provision the system.
If you provide both a passphrase and a key file, the role uses what you have provided first. If it does
not find any of these valid, it attempts to retrieve a passphrase from an existing binding.
PBD defines a binding as a mapping of a device to a slot. This means that you can have multiple
bindings for the same device. The default slot is slot 1.
The nbde_client role provides also the state variable. Use the present value for either creating a
new binding or updating an existing one. Contrary to a clevis luks bind command, you can use
state: present also for overwriting an existing binding in its device slot. Theabsent value removes a
specified binding.
Using the nbde_server System Role, you can deploy and manage a Tang server as part of an
automated disk encryption solution. This role supports the following features:
Rotating Tang keys
Deploying and backing up Tang keys
For a detailed reference on Network-Bound Disk Encryption (NBDE) role variables, install
the rhel-system-roles package, and see theREADME.md and README.html files in the
/usr/share/doc/rhel-system-roles/nbde_client/ and /usr/share/doc/rhel-system-
roles/nbde_server/ directories.
For example system-roles playbooks, install the rhel-system-roles package, and see the
/usr/share/ansible/roles/rhel-system-roles.nbde_server/examples/ directories.
For more information on RHEL System Roles, see Introduction to RHEL System Roles
12.2. USING THE NBDE_SERVER SYSTEM ROLE FOR SETTING UP

MULTIPLE TANG SERVERS
71
Follow the steps to prepare and apply an Ansible playbook containing your Tang server settings.
Prerequisites
configure with the nbde_server System Role.
The ansible-core package is installed on the control machine.
The rhel-system-roles package is installed on the system from which you want to run the
playbook.
Procedure
1. Prepare your playbook containing settings for Tang servers. You can either start from the
scratch, or use one of the example playbooks from the /usr/share/ansible/roles/rhel-
system-roles.nbde_server/examples/ directory.
# cp /usr/share/ansible/roles/rhel-system-roles.nbde_server/examples/simple_deploy.yml
./my-tang-playbook.yml
2. Edit the playbook in a text editor of your choice, for example:
# vi my-tang-playbook.yml
3. Add the required parameters. The following example playbook ensures deploying of your
Tang server and a key rotation:
---
- hosts: all
vars:
nbde_server_rotate_keys: yes
roles:
- rhel-system-roles.nbde_server
4. Apply the finished playbook:
# ansible-playbook -i host1,host2,host3 my-tang-playbook.yml
IMPORTANT
To ensure that networking for a Tang pin is available during early boot by using the
grubby tool on the systems where Clevis is installed:
# grubby --update-kernel=ALL --args="rd.neednet=1"
For more information, install the rhel-system-roles package, and see the
/usr/share/doc/rhel-system-roles/nbde_server/ and usr/share/ansible/roles/rhel-system-
roles.nbde_server/ directories.
72
12.3. USING THE NBDE_CLIENT SYSTEM ROLE FOR SETTING UP

MULTIPLE CLEVIS CLIENTS
Follow the steps to prepare and apply an Ansible playbook containing your Clevis client settings.
NOTE
The nbde_client System Role supports only Tang bindings. This means that you
cannot use it for TPM2 bindings at the moment.
Prerequisites
configure with the nbde_client System Role.
The rhel-system-roles package is installed on the system from which you want to run the
playbook.
Procedure
1. Prepare your playbook containing settings for Clevis clients. You can either start from the
scratch, or use one of the example playbooks from the /usr/share/ansible/roles/rhel-
system-roles.nbde_client/examples/ directory.
# cp /usr/share/ansible/roles/rhel-system-roles.nbde_client/examples/high_availability.yml
./my-clevis-playbook.yml
2. Edit the playbook in a text editor of your choice, for example:
# vi my-clevis-playbook.yml
3. Add the required parameters. The following example playbook configures Clevis clients for
automated unlocking of two LUKS-encrypted volumes by when at least one of two Tang
servers is available:
---
- hosts: all
vars:
nbde_client_bindings:
- device: /dev/rhel/root
encryption_key_src: /etc/luks/keyfile
servers:
- http://server1.example.com
- device: /dev/rhel/swap
encryption_key_src: /etc/luks/keyfile
servers:
73
roles:
- rhel-system-roles.nbde_client
4. Apply the finished playbook:
# ansible-playbook -i host1,host2,host3 my-clevis-playbook.yml
IMPORTANT
To ensure that networking for a Tang pin is available during early boot by using the
grubby tool on the system where Clevis is installed:
# grubby --update-kernel=ALL --args="rd.neednet=1"
For details about the parameters and additional information about the nbde_client System
Role, install the rhel-system-roles package, and see the/usr/share/doc/rhel-system-
roles/nbde_client/ and /usr/share/ansible/roles/rhel-system-roles.nbde_client/ directories.
74
CHAPTER 13. REQUESTING CERTIFICATES USING RHEL SYSTEM ROLES
CHAPTER 13. REQUESTING CERTIFICATES USING RHEL

SYSTEM ROLES
You can use the Certificate System Role to issue and manage certificates.
This chapter covers the following topics:
The Certificate System Role
Requesting a new self-signed certificate using the Certificate System Role
Requesting a new certificate from IdM CA using the Certificate System Role
13.1. THE CERTIFICATE SYSTEM ROLE

Using the Certificate System Role, you can manage issuing and renewing TLS and SSL certificates
using Ansible Core.
The role uses certmonger as the certificate provider, and currently supports issuing and renewing
self-signed certificates and using the IdM integrated certificate authority (CA).
You can use the following variables in your Ansible playbook with the Certificate System Role:
certificate_wait
to specify if the task should wait for the certificate to be issued.
certificate_requests
to represent each certificate to be issued and its parameters.
For details about the parameters used in the certificate_requests variable and additional
information about the certificate System Role, see the /usr/share/ansible/roles/rhel-
system-roles.certificate/README.md file.
For details about RHEL System Roles and how to apply them, see Getting started with
RHEL System Roles.
13.2. REQUESTING A NEW SELF-SIGNED CERTIFICATE USING THE

CERTIFICATE SYSTEM ROLE
With the Certificate System Role, you can use Ansible Core to issue self-signed certificates.
This process uses the certmonger provider and requests the certificate through thegetcert
command.
NOTE
By default, certmonger automatically tries to renew the certificate before it expires.

You can disable this by setting the auto_renew parameter in the Ansible playbook to
no.
Prerequisites
75
You have the rhel-system-roles package installed on the system from which you want to
run the playbook.
RHEL System Roles.
Procedure
1. Optional: Create an inventory file, for exampleinventory.file:
$ touch inventory.file
2. Open your inventory file and define the hosts on which you want to request the certificate,
for example:
[webserver]
server.idm.example.com
3. Create a playbook file, for example request-certificate.yml:
Set hosts to include the hosts on which you want to request the certificate, such as
webserver.
Set the certificate_requests variable to include the following:
Set the name parameter to the desired name of the certificate, such asmycert.
Set the dns parameter to the domain to be included in the certificate, such as
*.example.com.
Set the ca parameter to self-sign.
Set the rhel-system-roles.certificate role under roles.

This is the playbook file for this example:
---
- hosts: webserver
vars:
certificate_requests:
- name: mycert
dns: "*.example.com"
ca: self-sign
roles:
- rhel-system-roles.certificate
4. Save the file.
$ ansible-playbook -i inventory.file request-certificate.yml
76
13.3. REQUESTING A NEW CERTIFICATE FROM IDM CA USING THE

CERTIFICATE SYSTEM ROLE
With the Certificate System Role, you can use anible-core to issue certificates while using an IdM
server with an integrated certificate authority (CA). Therefore, you can efficiently and consistently
manage the certificate trust chain for multiple systems when using IdM as the CA.
This process uses the certmonger provider and requests the certificate through thegetcert
command.
NOTE

no.
Prerequisites
run the playbook.
RHEL System Roles.
Procedure
for example:
[webserver]
webserver.
77
www.example.com.
Set the principal parameter to specify the Kerberos principal, such as

HTTP/www.example.com@EXAMPLE.COM.
Set the ca parameter to ipa.

---
- hosts: webserver
vars:
- name: mycert
dns: www.example.com
principal: HTTP/www.example.com@EXAMPLE.COM
ca: ipa
roles:
4. Save the file.
13.4. SPECIFYING COMMANDS TO RUN BEFORE OR AFTER

CERTIFICATE ISSUANCE USING THE CERTIFICATE SYSTEM ROLE
With the Certificate System Role, you can use Ansible Core to execute a command before and after
a certificate is issued or renewed.
In the following example, the administrator ensures stopping the httpd service before a self-signed
certificate for www.example.com is issued or renewed, and restarting it afterwards.
NOTE

no.
Prerequisites
78
run the playbook.
RHEL System Roles.
Procedure
for example:
[webserver]
webserver.
www.example.com.
Set the ca parameter to the CA you want to use to issue the certificate, such as
self-sign.
Set the run_before parameter to the command you want to execute before this
certificate is issued or renewed, such as systemctl stop httpd.service.
Set the run_after parameter to the command you want to execute after this
certificate is issued or renewed, such as systemctl start httpd.service.

---
- hosts: webserver
vars:
- name: mycert
dns: www.example.com
ca: self-sign
run_before: systemctl stop httpd.service
run_after: systemctl start httpd.service
roles:
79
4. Save the file.
80
CHAPTER 14. CONFIGURING KDUMP USING RHEL SYSTEM ROLES
CHAPTER 14. CONFIGURING KDUMP USING RHEL SYSTEM

ROLES
To manage kdump using Ansible, you can use the kdump role, which is one of the RHEL System
Roles available in RHEL 8.
Using the kdump enables you to specify where to save the contents of the system’s memory for
later analysis.
For more information about RHEL System Roles and how to apply them, see Introduction to RHEL
System Roles.
14.1. THE KDUMP RHEL SYSTEM ROLE

The kdump System Role enables you to set basic kernel dump parameters on multiple systems.
14.2. KDUMP ROLE PARAMETERS

The parameters used for the kdump RHEL System Roles are:
Role Variable Description
kdump_path The path to which vmcore is written. If

kdump_target is not null, path is relative to that
dump target. Otherwise, it must be an absolute path
in the root file system.
The makedumpfile(8) man page.
For details about the parameters used in kdump and additional information about the
kdump System Role, see the /usr/share/ansible/roles/rhel-system-roles.tlog/README.md
file.
14.3. CONFIGURING KDUMP USING RHEL SYSTEM ROLES

You can set basic kernel dump parameters on multiple systems using the kdump System Role by
running an Ansible playbook.

WARNING
The kdump role replaces the kdump configuration of the managed hosts
entirely by replacing the /etc/kdump.conf file. Additionally, if the kdump role is
applied, all previous kdump settings are also replaced, even if they are not
specified by the role variables, by replacing the /etc/sysconfig/kdump file.
81
Prerequisites
You have Red Hat Ansible Engine installed on the system from which you want to run the
playbook.
NOTE
You do not have to have Red Hat Ansible Automation Platform installed on
the systems on which you want to deploy the kdump solution.
run the playbook.
You have an inventory file which lists the systems on which you want to deploy kdump.
Procedure
---
- hosts: kdump-test
vars:
kdump_path: /var/crash
roles:
- rhel-system-roles.kdump
For a detailed reference on kdump role variables, see the README.md or README.html
files in the /usr/share/doc/rhel-system-roles/kdump directory.
See Applying a system role.
Documentation installed with the rhel-system-roles package /usr/share/ansible/roles/rhel-

system-roles.kdump/README.html
82
CHAPTER 15. MANAGING LOCAL STORAGE USING RHEL SYSTEM ROLES
CHAPTER 15. MANAGING LOCAL STORAGE USING RHEL

SYSTEM ROLES
To manage LVM and local file systems (FS) using Ansible, you can use the storage role, which is
one of the RHEL System Roles available in RHEL 8.
Using the storage role enables you to automate administration of file systems on disks and logical
volumes on multiple machines and across all versions of RHEL starting with RHEL 7.7.
For more information about RHEL System Roles and how to apply them, see Introduction to RHEL
System Roles.
15.1. INTRODUCTION TO THE STORAGE ROLE

The storage role can manage:
File systems on disks which have not been partitioned
Complete LVM volume groups including their logical volumes and file systems
With the storage role you can perform the following tasks:
Create a file system
Remove a file system
Mount a file system
Unmount a file system
Create LVM volume groups
Remove LVM volume groups
Create logical volumes
Remove logical volumes
Create RAID volumes
Remove RAID volumes
Create LVM pools with RAID
Remove LVM pools with RAID
15.2. PARAMETERS THAT IDENTIFY A STORAGE DEVICE IN THE

STORAGE SYSTEM ROLE
Your storage role configuration affects only the file systems, volumes, and pools that you list in the
following variables.
storage_volumes
List of file systems on all unpartitioned disks to be managed.
Partitions are currently unsupported.
83
storage_pools
List of pools to be managed.
Currently the only supported pool type is LVM. With LVM, pools represent volume groups (VGs).
Under each pool there is a list of volumes to be managed by the role. With LVM, each volume
corresponds to a logical volume (LV) with a file system.
15.3. EXAMPLE ANSIBLE PLAYBOOK TO CREATE AN XFS FILE

SYSTEM ON A BLOCK DEVICE
This section provides an example Ansible playbook. This playbook applies the storage role to create
an XFS file system on a block device using the default parameters.

WARNING
The storage role can create a file system only on an unpartitioned, whole disk or
a logical volume (LV). It cannot create the file system on a partition.
Example 15.1. A playbook that creates XFS on /dev/sdb
---
- hosts: all
vars:
storage_volumes:
- name: barefs
type: disk
disks:
- sdb
fs_type: xfs
roles:
- rhel-system-roles.storage
The volume name (barefs in the example) is currently arbitrary. Thestorage role
identifies the volume by the disk device listed under the disks: attribute.
You can omit the fs_type: xfs line because XFS is the default file system in RHEL 8.
To create the file system on an LV, provide the LVM setup under the disks: attribute,
including the enclosing volume group. For details, see Example Ansible playbook to
manage logical volumes.
Do not provide the path to the LV device.
The /usr/share/ansible/roles/rhel-system-roles.storage/README.md file.
15.4. EXAMPLE ANSIBLE PLAYBOOK TO PERSISTENTLY MOUNT A

84
15.4. EXAMPLE ANSIBLE PLAYBOOK TO PERSISTENTLY MOUNT A

FILE SYSTEM
This section provides an example Ansible playbook. This playbook applies the storage role to
immediately and persistently mount an XFS file system.
Example 15.2. A playbook that mounts a file system on /dev/sdb to /mnt/data
---
- hosts: all
vars:
storage_volumes:
- name: barefs
type: disk
disks:
- sdb
fs_type: xfs
mount_point: /mnt/data
roles:
This playbook adds the file system to the /etc/fstab file, and mounts the file system
immediately.
If the file system on the /dev/sdb device or the mount point directory do not exist, the
playbook creates them.
15.5. EXAMPLE ANSIBLE PLAYBOOK TO MANAGE LOGICAL

VOLUMES
an LVM logical volume in a volume group.
Example 15.3. A playbook that creates a mylv logical volume in the myvg volume group
- hosts: all
vars:
storage_pools:
- name: myvg
disks:
- sda
- sdb
- sdc
volumes:
- name: mylv
size: 2G
fs_type: ext4
85
mount_point: /mnt
roles:
The myvg volume group consists of the following disks:
/dev/sda
/dev/sdb
/dev/sdc
If the myvg volume group already exists, the playbook adds the logical volume to the
volume group.
If the myvg volume group does not exist, the playbook creates it.
The playbook creates an Ext4 file system on the mylv logical volume, and persistently
mounts the file system at /mnt.
15.6. EXAMPLE ANSIBLE PLAYBOOK TO ENABLE ONLINE BLOCK

DISCARD
This section provides an example Ansible playbook. This playbook applies the storage role to mount
an XFS file system with online block discard enabled.
Example 15.4. A playbook that enables online block discard on /mnt/data/
---
- hosts: all
vars:
storage_volumes:
- name: barefs
type: disk
disks:
- sdb
fs_type: xfs
mount_options: discard
roles:
Example Ansible playbook to persistently mount a file system
86
15.7. EXAMPLE ANSIBLE PLAYBOOK TO CREATE AND MOUNT AN

EXT4 FILE SYSTEM
and mount an Ext4 file system.
Example 15.5. A playbook that creates Ext4 on /dev/sdb and mounts it at /mnt/data
---
- hosts: all
vars:
storage_volumes:
- name: barefs
type: disk
disks:
- sdb
fs_type: ext4
fs_label: label-name
roles:
The playbook creates the file system on the /dev/sdb disk.
The playbook persistently mounts the file system at the /mnt/data directory.
The label of the file system is label-name.
15.8. EXAMPLE ANSIBLE PLAYBOOK TO CREATE AND MOUNT AN

EXT3 FILE SYSTEM
and mount an Ext3 file system.
Example 15.6. A playbook that creates Ext3 on /dev/sdb and mounts it at/mnt/data
---
- hosts: all
vars:
storage_volumes:
- name: barefs
type: disk
disks:
- sdb
fs_type: ext3
87
roles:
The playbook creates the file system on the /dev/sdb disk.
The playbook persistently mounts the file system at the /mnt/data directory.
The label of the file system is label-name.
15.9. EXAMPLE ANSIBLE PLAYBOOK TO RESIZE AN EXISTING EXT4

OR EXT3 FILE SYSTEM USING THE STORAGE RHEL SYSTEM ROLE
This section provides an example Ansible playbook. This playbook applies the storage role to resize
an existing Ext4 or Ext3 file system on a block device.
Example 15.7. A playbook that set up a single volume on a disk
---
- name: Create a disk device mounted on /opt/barefs
- hosts: all
vars:
storage_volumes:
- name: barefs
type: disk
disks:
- /dev/sdb
size: 12 GiB
fs_type: ext4
mount_point: /opt/barefs
roles:
If the volume in the previous example already exists, to resize the volume, you need to run
the same playbook, just with a different value for the parameter size. For example:
Example 15.8. A playbook that resizes ext4 on /dev/sdb
---
- name: Create a disk device mounted on /opt/barefs
- hosts: all
vars:
storage_volumes:
- name: barefs
type: disk
disks:
- /dev/sdb
88
size: 10 GiB
fs_type: ext4
mount_point: /opt/barefs
roles:
The volume name (barefs in the example) is currently arbitrary. The storage role
NOTE
Using the Resizing action in other file systems can destroy the data on the device
you are working on.
15.10. EXAMPLE ANSIBLE PLAYBOOK TO RESIZE AN EXISTING FILE

SYSTEM ON LVM USING THE STORAGE RHEL SYSTEM ROLE
This section provides an example Ansible playbook. This playbook applies the storage RHEL System
Role to resize an LVM logical volume with a file system.

WARNING
Using the Resizing action in other file systems can destroy the data on the
device you are working on.
Example 15.9. A playbook that resizes existing mylv1 and myvl2 logical volumes in the myvg
volume group
---
- hosts: all
vars:
storage_pools:
- name: myvg
disks:
- /dev/sda
- /dev/sdb
- /dev/sdc
volumes:
- name: mylv1
size: 10 GiB
fs_type: ext4
mount_point: /opt/mount1
89
- name: mylv2
size: 50 GiB
fs_type: ext4
mount_point: /opt/mount2
- name: Create LVM pool over three disks

incude_role:
name: rhel-system-roles.storage
This playbook resizes the following existing file systems:
The Ext4 file system on the mylv1 volume, which is mounted at/opt/mount1, resizes
to 10 GiB.
The Ext4 file system on the mylv2 volume, which is mounted at/opt/mount2, resizes
to 50 GiB.
15.11. EXAMPLE ANSIBLE PLAYBOOK TO CREATE A SWAP PARTITION

USING THE STORAGE RHEL SYSTEM ROLE
a swap partition, if it does not exist, or to modify the swap partition, if it already exist, on a block
device using the default parameters.
Example 15.10. A playbook that creates or modify an existing XFS on /dev/sdb
---
- name: Create a disk device with swap
- hosts: all
vars:
storage_volumes:
- name: swap_fs
type: disk
disks:
- /dev/sdb
size: 15 GiB
fs_type: swap
roles:
The volume name (swap_fs in the example) is currently arbitrary. Thestorage role
15.12. CONFIGURING A RAID VOLUME USING THE STORAGE SYSTEM

90
15.12. CONFIGURING A RAID VOLUME USING THE STORAGE SYSTEM

ROLE
With the storage System Role, you can configure a RAID volume on RHEL using Red Hat Ansible
Automation Platform. In this section you will learn how to set up an Ansible playbook with the
available parameters to configure a RAID volume to suit your requirements.
Prerequisites
playbook.
NOTE
the systems on which you want to deploy the storage solution.
run the playbook.
You have an inventory file detailing the systems on which you want to deploy a RAID
volume using the storage System Role.
Procedure
- hosts: all
vars:
storage_safe_mode: false
storage_volumes:
- name: data
type: raid
disks: [sdd, sde, sdf, sdg]
raid_level: raid0
raid_chunk_size: 32 KiB
state: present
roles:
- name: rhel-system-roles.storage

WARNING
Device names can change in certain circumstances; for example, when

you add a new disk to a system. Therefore, to prevent data loss, we do
not recommend using specific disk names in the playbook.
2. Optional. Verify playbook syntax.
91
# ansible-playbook -i inventory.file /path/to/file/playbook.yml
Managing RAID.
15.13. CONFIGURING AN LVM POOL WITH RAID USING THE STORAGE

SYSTEM ROLE
With the storage System Role, you can configure an LVM pool with RAID on RHEL using Red Hat
Ansible Automation Platform. In this section you will learn how to set up an Ansible playbook with
the available parameters to configure an LVM pool with RAID.
Prerequisites
playbook.
NOTE
the systems on which you want to deploy the storage solution.
run the playbook.
You have an inventory file detailing the systems on which you want to configure an LVM
pool with RAID using the storage System Role.
Procedure
- hosts: all
vars:
storage_safe_mode: false
storage_pools:
- name: my_pool
type: lvm
disks: [sdh, sdi]
raid_level: raid1
volumes:
- name: my_pool
size: "1 GiB"
mount_point: "/mnt/app/shared"
fs_type: xfs
92
state: present
roles:
- name: rhel-system-roles.storage
NOTE
To create an LVM pool with RAID, you must specify the RAID type using the
raid_level parameter.
2. Optional. Verify playbook syntax.
Managing RAID.
15.14. EXAMPLE ANSIBLE PLAYBOOK TO COMPRESS AND

DEDUPLICATE A VDO VOLUME ON LVM USING THE STORAGE RHEL
SYSTEM ROLE
Role to enable compression and deduplication to a Logical Manager Volumes (LVM) using the
Virtual Data Optimizer (VDO) volume.
Example 15.11. A playbook that creates a mylv1 LVM VDO volume in themyvg volume group
---
- name: Create LVM VDO volume under volume group 'myvg'
hosts: all
roles:
-rhel-system-roles.storage
vars:
storage_pools:
- name: myvg
disks:
- /dev/sdb
volumes:
- name: mylv1
compression: true
deduplication: true
vdo_pool_size: 10 GiB
size: 30 GiB
mount_point: /mnt/app/shared
93
In this example, the compression and deduplication pools are set to true, which specifies that the
VDO is used. The following describes the usage of these parameters:
The deduplication is used to deduplicate the duplicated data stored on the storage volume.
The compression is used to compress the data stored on the storage volume, which results
in more storage capacity.
The vdo_pool_size specifies the actual size the volume takes on the device. The virtual size
of VDO volume is set by the size parameter. NOTE: Because of the storage role use of LVM
VDO, only one volume per pool can use the compression and deduplication.
15.15. CREATING A LUKS ENCRYPTED VOLUME USING THE STORAGE

ROLE
You can use the storage role to create and configure a volume encrypted with LUKS by running an
Ansible playbook.
Prerequisites
playbook.
NOTE
the systems on which you want to create the volume.
You have the rhel-system-roles package installed on the Ansible controller.
You have an inventory file detailing the systems on which you want to deploy a LUKS
encrypted volume using the storage System Role.
Procedure
- hosts: all
vars:
storage_volumes:
- name: barefs
type: disk
disks:
- sdb
fs_type: xfs
encryption: true
encryption_password: your-password
roles:
2. Optional: Verify playbook syntax:
94
Encrypting block devices using LUKS
/usr/share/ansible/roles/rhel-system-roles.storage/README.md file
15.16. EXAMPLE ANSIBLE PLAYBOOK TO EXPRESS POOL VOLUME

SIZES AS PERCENTAGE USING THE STORAGE RHEL SYSTEM ROLE
Role to enable you to express Logical Manager Volumes (LVM) volume sizes as a percentage of the
pool’s total size.
Example 15.12. A playbook that express volume sizes as a percentage of the pool’s total size
---
- name: Express volume sizes as a percentage of the pool's total size
hosts: all
roles
vars:
storage_pools:
- name: myvg
disks:
- /dev/sdb
volumes:
- name: data
size: 60%
mount_point: /opt/mount/data
- name: web
size: 30%
mount_point: /opt/mount/web
- name: cache
size: 10%
mount_point: /opt/cache/mount
This example specifies the size of LVM volumes as a percentage of the pool size, for example:
"60%". Additionally, you can also specify the size of LVM volumes as a percentage of the pool size
in a human-readable size of the file system, for example, "10g" or "50 GiB".

/usr/share/doc/rhel-system-roles/storage/
/usr/share/ansible/roles/rhel-system-roles.storage/
95
CHAPTER 16. CONFIGURING TIME SYNCHRONIZATION USING

RHEL SYSTEM ROLES
With the timesync RHEL System Role, you can manage time synchronization on multiple target
machines on RHEL using Red Hat Ansible Automation Platform.
16.1. THE TIMESYNC SYSTEM ROLE

You can manage time synchronization on multiple target machines using the timesync RHEL
System Role.
The timesync role installs and configures an NTP or PTP implementation to operate as an NTP
client or PTP replica in order to synchronize the system clock with NTP servers or grandmasters in
PTP domains.
Note that using the timesync role also facilitates themigration to chrony, because you can use the
same playbook on all versions of Red Hat Enterprise Linux starting with RHEL 6 regardless of
whether the system uses ntp or chrony to implement the NTP protocol.
16.2. APPLYING THE TIMESYNC SYSTEM ROLE FOR A SINGLE POOL

OF SERVERS
The following example shows how to apply the timesync role in a situation with just one pool of
servers.

WARNING
The timesync role replaces the configuration of the given or detected provider
service on the managed host. Previous settings are lost, even if they are not
specified in the role variables. The only preserved setting is the choice of
provider if the timesync_ntp_provider variable is not defined.
Prerequisites
playbook.
NOTE
the systems on which you want to deploy the timesync solution.
run the playbook.
You have an inventory file which lists the systems on which you want to deploy timesync
System Role.
Procedure
96
CHAPTER 16. CONFIGURING TIME SYNCHRONIZATION USING RHEL SYSTEM ROLES
Procedure
---
- hosts: timesync-test
vars:
timesync_ntp_servers:
- hostname: 2.rhel.pool.ntp.org
pool: yes
iburst: yes
roles:
16.3. APPLYING THE TIMESYNC SYSTEM ROLE ON CLIENT SERVERS

You can use the timesync role to enable Network Time Security (NTS) on NTP clients. Network
Time Security (NTS) is an authentication mechanism specified for Network Time Protocol (NTP). It
verifies that NTP packets exchanged between the server and client are not altered.

WARNING
The timesync role replaces the configuration of the given or detected provider
service on the managed host. Previous settings are lost even if they are not
specified in the role variables. The only preserved setting is the choice of
provider if the timesync_ntp_provider variable is not defined.
Prerequisites
You do not have to have Red Hat Ansible Automation Platform installed on the systems on
which you want to deploy the timesync solution.
run the playbook.
You have an inventory file which lists the systems on which you want to deploy the
timesync System Role.
The chrony NTP provider version is 4.0 or later.
Procedure
97
1. Create a playbook.yml file with the following content:
---
- hosts: timesync-test
vars:
- hostname: ptbtime1.ptb.de
iburst: yes
nts: yes
roles:
ptbtime1.ptb.de is an example of public server. You may want to use a different public
server or your own server.
Verification
1. Perform a test on the client machine:
# chronyc -N authdata
Name/IP address Mode KeyID Type KLen Last Atmp NAK Cook CLen
=====================================================================
ptbtime1.ptb.de NTS 1 15 256 157 0 0 8 100
2. Check that the number of reported cookies is larger than zero.
chrony.conf(5) man page
16.4. TIMESYNC SYSTEM ROLES VARIABLES

You can pass the following variable to the timesync role:
Role variable settings Description
hostname: host.example.com Hostname or address of the server
minpoll: number Minimum polling interval. Default: 6
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CHAPTER 16. CONFIGURING TIME SYNCHRONIZATION USING RHEL SYSTEM ROLES
Role variable settings Description
maxpoll: number Maximum polling interval. Default: 10
iburst: yes Flag enabling fast initial synchronization. Default: no
pool: yes Flag indicating that each resolved address of the

hostname is a separate NTP server. Default: no
nts: yes Flag to enable Network Time Security (NTS). Default:

no. Supported only with chrony >= 4.0.
For a detailed reference on timesync role variables, install the rhel-system-roles package,
and see the README.md or README.html files in the /usr/share/doc/rhel-system-
roles/timesync directory.
99
CHAPTER 17. MONITORING PERFORMANCE USING RHEL

SYSTEM ROLES
As a system administrator, you can use the metrics RHEL System Role to monitor the performance
of a system.
17.1. INTRODUCTION TO THE METRICS SYSTEM ROLE

configuration interface to remotely manage multiple RHEL systems. The metrics System Role
configures performance analysis services for the local system and, optionally, includes a list of
remote systems to be monitored by the local system. The metrics System Role enables you to use
pcp to monitor your systems performance without having to configurepcp separately, as the set-
up and deployment of pcp is handled by the playbook.
Table 17.1. Metrics system role variables
Role variable Description Example usage
metrics_monitored_hosts List of remote hosts to be metrics_monitored_hosts:

analyzed by the target host. ["webserver.example.com",
These hosts will have metrics "database.example.com"]
recorded on the target host, so
ensure enough disk space exists
below /var/log for each host.
metrics_retention_days Configures the number of days metrics_retention_days: 14

for performance data retention
before deletion.
metrics_graph_service A boolean flag that enables the metrics_graph_service: no

host to be set up with services for
performance data visualization via
pcp and grafana . Set to false by
default.
metrics_query_service A boolean flag that enables the metrics_query_service: no

host to be set up with time series
query services for querying
recorded pcp metrics via redis.
Set to false by default.
metrics_provider Specifies which metrics collector metrics_provider: "pcp"

to use to provide metrics.
Currently, pcp is the only
supported metrics provider.
NOTE
For details about the parameters used in metrics_connections and additional

information about the metrics System Role, see the /usr/share/ansible/roles/rhel-
system-roles.metrics/README.md file.
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CHAPTER 17. MONITORING PERFORMANCE USING RHEL SYSTEM ROLES
17.2. USING THE METRICS SYSTEM ROLE TO MONITOR YOUR LOCAL

SYSTEM WITH VISUALIZATION
This procedure describes how to use the metrics RHEL System Role to monitor your local system
while simultaneously provisioning data visualization via Grafana.
Prerequisites
You have the rhel-system-roles package installed on the machine you want to monitor.
Procedure
1. Configure localhost in the the/etc/ansible/hosts Ansible inventory by adding the following

content to the inventory:
localhost ansible_connection=local
2. Create an Ansible playbook with the following content:
---
- hosts: localhost
vars:
metrics_graph_service: yes
roles:
- rhel-system-roles.metrics
3. Run the Ansible playbook:
# ansible-playbook name_of_your_playbook.yml
NOTE
Since the metrics_graph_service boolean is set to value="yes",Grafana is

automatically installed and provisioned with pcp added as a data source.
4. To view visualization of the metrics being collected on your machine, access the grafana
web interface as described in Accessing the Grafana web UI.
17.3. USING THE METRICS SYSTEM ROLE TO SETUP A FLEET OF

INDIVIDUAL SYSTEMS TO MONITOR THEMSELVES
This procedure describes how to use the metrics System Role to set up a fleet of machines to
monitor themselves.
Prerequisites
You have the rhel-system-roles package installed on the machine you want to use to run
the playbook.
101
You have the SSH connection established.
Procedure
1. Add the name or IP of the machines you wish to monitor via the playbook to the
/etc/ansible/hosts Ansible inventory file under an identifying group name enclosed in
brackets:
[remotes]
webserver.example.com
database.example.com
---
- hosts: remotes
vars:
metrics_retention_days: 0
roles:
# ansible-playbook name_of_your_playbook.yml -k
Where the -k prompt for password to connect to remote system.
17.4. USING THE METRICS SYSTEM ROLE TO MONITOR A FLEET OF

MACHINES CENTRALLY VIA YOUR LOCAL MACHINE
This procedure describes how to use the metrics System Role to set up your local machine to
centrally monitor a fleet of machines while also provisioning visualization of the data via grafana
and querying of the data via redis.
Prerequisites
the playbook.
Procedure
---
- hosts: localhost
vars:
metrics_graph_service: yes
metrics_query_service: yes
metrics_retention_days: 10
102
metrics_monitored_hosts: ["database.example.com", "webserver.example.com"]

roles:
NOTE
Since the metrics_graph_service and metrics_query_service booleans are

set to value="yes", grafana is automatically installed and provisioned withpcp
added as a data source with the pcp data recording indexed intoredis,
allowing the pcp querying language to be used for complex querying of the
data.
3. To view graphical representation of the metrics being collected centrally by your machine
and to query the data, access the grafana web interface as described inAccessing the
Grafana web UI.
17.5. SETTING UP AUTHENTICATION WHILE MONITORING A SYSTEM

USING THE METRICS SYSTEM ROLE
PCP supports the scram-sha-256 authentication mechanism through the Simple Authentication
Security Layer (SASL) framework. The metrics RHEL System Role automates the steps to setup
authentication using the scram-sha-256 authentication mechanism. This procedure describes how
to setup authentication using the metrics RHEL System Role.
Prerequisites
the playbook.
Procedure
1. Include the following variables in the Ansible playbook you want to setup authentication
for:
---
vars:
metrics_username: your_username
metrics_password: your_password
Verification steps
Verify the sasl configuration:
103
# pminfo -f -h "pcp://ip_adress?username=your_username" disk.dev.read

Password:
disk.dev.read
inst [0 or "sda"] value 19540
ip_adress should be replaced by the IP adress of the host.
17.6. USING THE METRICS SYSTEM ROLE TO CONFIGURE AND

ENABLE METRICS COLLECTION FOR SQL SERVER
This procedure describes how to use the metrics RHEL System Role to automate the configuration
and enabling of metrics collection for Microsoft SQL Server via pcp on your local system.
Prerequisites
You have the rhel-system-roles package installed on the machine you want to monitor.
You have installed Microsoft SQL Server for Red Hat Enterprise Linux and established a
'trusted' connection to an SQL server.
You have installed the Microsoft ODBC driver for SQL Server for Red Hat Enterprise Linux.
Procedure
1. Configure localhost in the the/etc/ansible/hosts Ansible inventory by adding the following

content to the inventory:
localhost ansible_connection=local
2. Create an Ansible playbook that contains the following content:
---
- hosts: localhost
roles:
- role: rhel-system-roles.metrics
vars:
metrics_from_mssql: yes
Verification steps
Use the pcp command to verify that SQL Server PMDA agent (mssql) is loaded and
running:
# pcp
platform: Linux rhel82-2.local 4.18.0-167.el8.x86_64 #1 SMP Sun Dec 15 01:24:23 UTC
2019 x86_64
hardware: 2 cpus, 1 disk, 1 node, 2770MB RAM
104
timezone: PDT+7
services: pmcd pmproxy
pmcd: Version 5.0.2-1, 12 agents, 4 clients
pmda: root pmcd proc pmproxy xfs linux nfsclient mmv kvm mssql
jbd2 dm
pmlogger: primary logger: /var/log/pcp/pmlogger/rhel82-2.local/20200326.16.31
pmie: primary engine: /var/log/pcp/pmie/rhel82-2.local/pmie.log
For more information about using Performance Co-Pilot for Microsoft SQL Server, see this
Red Hat Developers Blog post.
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CHAPTER 18. CONFIGURING MICROSOFT SQL SERVER USING

MICROSOFT.SQL.SERVER ANSIBLE ROLE
As an administrator, you can use the microsoft.sql.server Ansible role to install, configure, and start
Microsoft SQL Server (SQL Server). The microsoft.sql.server Ansible role optimizes your operating
system to improve performance and throughput for the SQL Server. The role simplifies and
automates the configuration of your RHEL host with recommended settings to run the SQL Server
workloads.
18.1. PREREQUISITES
2 GB of RAM
root access to the managed node where you want to configure SQL Server
Pre-configured firewall
You must enable the connection on the SQL Server TCP port set with the mssql_tcp_port
variable. If you do not define this variable, the role defaults to the TCP port number 1443.
To add a new port, use:
# firewall-cmd --add-port=xxxx/tcp --permanent

# firewall-cmd --reload
Replace xxxx with the TCP port number then reload the firewall rules.
Optional: Create a file with the.sql extension containing the SQL statements and
procedures to input them to SQL Server.
18.2. INSTALLING MICROSOFT.SQL.SERVER ANSIBLE ROLE

The microsoft.sql.server Ansible role is part of theansible-collection-microsoft-sql package. For
more information, see How do I Download and Install Red Hat Ansible Engine?
If you do not have the Red Hat Ansible Engine Subscription, you can use the limited supported
version of Ansible Engine provided with your Red Hat Enterprise Linux subscription.
To enable the limited supported version of Ansible Engine and install microsoft.sql.server Ansible
roles, follow the steps outlined in the procedure below using the command line.
Prerequisites
root access
Procedure
1. Refresh your subscriptions:
2. Enable the RHEL Ansible subscription:
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CHAPTER 18. CONFIGURING MICROSOFT SQL SERVER USING MICROSOFT.SQL.SERVER ANSIBLE ROLE
3. Install Ansible:
4. Install microsoft.sql.server Ansible role:
# yum install ansible-collection-microsoft-sql
18.3. INSTALLING AND CONFIGURING SQL SERVER USING

MICROSOFT.SQL.SERVER ANSIBLE ROLE
You can use the microsoft.sql.server Ansible role to install and configure SQL server.
Prerequisites
The Ansible inventory is created
Procedure
1. Create a file with the .yml extension. For example, mssql-server.yml.
2. Add the following content to your .yml file:
---
- hosts: all
vars:
mssql_accept_microsoft_odbc_driver_17_for_sql_server_eula: true
mssql_accept_microsoft_cli_utilities_for_sql_server_eula: true
mssql_accept_microsoft_sql_server_standard_eula: true
mssql_password: <password>
mssql_edition: Developer
mssql_tcp_port: 1443
roles:
- microsoft.sql.server
Replace <password> with your SQL Server password.
3. Run the mssql-server.yml ansible playbook:
# ansible-playbook mssql-server.yml
18.4. TLS VARIABLES

The following variables are available for configuring the Transport Level Security (TLS).
Table 18.1. TLS role variables
Role variable Description
107
mssql_tls_enable This variable enables or disables TLS encryption.
The microsoft.sql.server Ansible role performs

following tasks when the variable is set to true:
Copies TLS certificate to

/etc/pki/tls/certs/ on the SQL Server
Copies private key to /etc/pki/tls/private/

on the SQL Server
Configures SQL Server to use TLS

certificate and private key to encrypt
connections
NOTE
You must have the TLS certificate

and private key on the Ansible
control node.
When set to false, the TLS encryption is disabled.

The role does not remove the existing certificate and
private key files.
mssql_tls_cert To define this variable, enter the path to the TLS

certificate file.
mssql_tls_private_key To define this variable, enter the path to the private

key file.
mssql_tls_version Define this variable to select which TSL version to

use.
The default is 1.2
mssql_tls_force Set this variable to true to replace the certificate and

private key files on the host. The files must exist
under /etc/pki/tls/certs/ and /etc/pki/tls/private/
directories.
The default is false.
18.5. ACCEPTING EULA FOR MLSERVICES

You must accept all the EULA for the open-source distributions of Python and R packages to
install the required SQL Server Machine Learning Services (MLServices).
See /usr/share/doc/mssql-server for the license terms.
Table 18.2. SQL Server Machine Learning Services EULA variables
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CHAPTER 18. CONFIGURING MICROSOFT SQL SERVER USING MICROSOFT.SQL.SERVER ANSIBLE ROLE
mssql_accept_microsoft_sql_server_standard_eula This variable determines whether to accept the terms

and conditions for installing the mssql-conf
package.
To accept the terms and conditions set this variable

to true.
18.6. ACCEPTING EULAS FOR MICROSOFT ODBC 17

You must accept all the EULAs to install the Microsoft Open Database Connectivity (ODBC) driver.
See /usr/share/doc/msodbcsql17/LICENSE.txt and /usr/share/doc/mssql-tools/LICENSE.txt for the

license terms.
Table 18.3. Microsoft ODBC 17 EULA variables
mssql_accept_microsoft_odbc_driver_17_for_sql_serv This variable determines whether to accept the terms

er_eula and conditions for installing the msodbcsql17
package.

to true.
mssql_accept_microsoft_cli_utilities_for_sql_server_e This variable determines whether to accept the terms

ula and conditions for installing the mssql-tools
package.

to true.
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CHAPTER 19. CONFIGURING A SYSTEM FOR SESSION

RECORDING USING THE TLOG RHEL SYSTEM ROLES
With the tlog RHEL System Role, you can configure a system for terminal session recording on
RHEL using Red Hat Ansible Automation Platform.
19.1. THE TLOG SYSTEM ROLE

You can configure a RHEL system for terminal session recording on RHEL using the tlog RHEL
System Role. The tlog package and its associated web console session player provide you with the
ability to record and play back user terminal sessions.
You can configure the recording to take place per user or user group via the SSSD service. All
terminal input and output is captured and stored in a text-based format in the system journal.
For more details on session recording in RHEL, see Recording Sessions
19.2. COMPONENTS AND PARAMETERS OF THE TLOG SYSTEM

ROLES
The Session Recording solution is composed of the following components:
The tlog utility
System Security Services Daemon (SSSD)
Optional: The web console interface
The parameters used for the tlog RHEL System Roles are:
Role Variable Description
tlog_use_sssd (default: yes) Configure session recording with SSSD, the

preferred way of managing recorded users or groups
tlog_scope_sssd (default: none) Configure SSSD recording scope - all / some / none
tlog_users_sssd (default: []) YAML list of users to be recorded
tlog_groups_sssd (default: []) YAML list of groups to be recorded
For details about the parameters used in tlog and additional information about the tlog
System Role, see the /usr/share/ansible/roles/rhel-system-roles.tlog/README.md file.
19.3. DEPLOYING THE TLOG RHEL SYSTEM ROLE

Follow these steps to prepare and apply an Ansible playbook to configure a RHEL system to log
recording data to the systemd journal.
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CHAPTER 19. CONFIGURING A SYSTEM FOR SESSION RECORDING USING THE TLOG RHEL SYSTEM ROLES
Prerequisites
You have set SSH keys for access from the control node to the target system where the
tlog System Role will be configured.
Procedure
---
- name: Deploy session recording
hosts: all
vars:
tlog_scope_sssd: some
tlog_users_sssd:
- recordeduser
roles:
- rhel-system-roles.tlog
Where,
tlog_scope_sssd:
some specifies you want to record only certain users and groups, notall or none.
tlog_users_sssd:
recordeduser specifies the user you want to record a session from. Note that this
does not add the user for you. You must set the user by yourself.
2. Optionally, verify the playbook syntax.
# ansible-playbook -i IP_Address /path/to/file/playbook.yml -v
As a result, the playbook installs the tlog role on the system you specified. It also creates an SSSD
configuration drop file that can be used by the users and groups that you define. SSSD parses and
reads these users and groups to overlay tlog session as the shell user. Additionally, if thecockpit
package is installed on the system, the playbook also installs the cockpit-session-recording
package, which is a Cockpit module that allows you to view and play recordings in the web console
interface.
Verification steps
To verify that the SSSD configuration drop file is created in the system, perform the following
steps:
1. Navigate to the folder where the SSSD configuration drop file is created:
111
# cd /etc/sssd/conf.d
2. Check the file content:
# cat /etc/sssd/conf.d/sssd-session-recording.conf
You can see that the file contains the parameters you set in the playbook.
19.4. DEPLOYING THE TLOG RHEL SYSTEM ROLE FOR EXCLUDING

LISTS OF GROUPS OR USERS
You can use the tlog System Role on RHEL to support the SSSD session recording configuration
options exclude_users and exclude_groups. Follow these steps to prepare and apply an Ansible
playbook to configure a RHEL system to exclude users or groups from having their sessions
recorded and logged in the systemd journal.
Prerequisites
You have set SSH keys for access from the control node to the target system on which you
want to configure the tlog System Role.
Procedure
---
- name: Deploy session recording excluding users and groups
hosts: all
vars:
tlog_scope_sssd: all
tlog_exclude_users_sssd:
- jeff
- james
tlog_exclude_groups_sssd:
- admins
roles:
- rhel-system-roles.tlog
Where,
tlog_scope_sssd:
all: specifies that you want to record all users and groups.
tlog_exclude_users_sssd:
user names: specifies the user names of the users you want to exclude from the
session recording.
112
tlog_exclude_groups_sssd:
admins specifies the group you want to exclude from the session recording.
2. Optionally, verify the playbook syntax;
# ansible-playbook -i IP_Address /path/to/file/playbook.yml -v
As a result, the playbook installs the tlog package on the system you specified. It also creates an
/etc/sssd/conf.d/sssd-session-recording.conf SSSD configuration drop file that can be used by
users and groups except those that you defined as excluded. SSSD parses and reads these users
and groups to overlap tlog session as the shell user. Additionally, if thecockpit package is installed
on the system, the playbook also installs the cockpit-session-recording package, which is aCockpit
module that allows you to view and play recordings in the web console interface.
NOTE
You are not able to record a session for users listed in the exclude_users list or if
they are a member of a group in the exclude_groups list.
Verification steps
To verify that the SSSD configuration drop file is created in the system, perform the following
steps:
1. Navigate to the folder where the SSSD configuration drop file is created:
# cd /etc/sssd/conf.d
2. Check the file content:
# cat sssd-session-recording.conf
You can see that the file contains the parameters you set in the playbook.
See the /usr/share/doc/rhel-system-roles/tlog/ and /usr/share/ansible/roles/rhel-system-

roles.tlog/ directories.
The Recording a session using the deployed tlog system role in the CLI.
19.5. RECORDING A SESSION USING THE DEPLOYED TLOG SYSTEM

ROLE IN THE CLI
Once you have deployed the tlog System Role in the system you have specified, you are able to
record a user terminal session using the command-line interface (CLI).
Prerequisites
113
You have deployed the tlog System Role in the target system.
The SSSD configuration drop file was created in the /etc/sssd/conf.d file.
Procedure
1. Create a user and assign a password for this user:
# useradd recordeduser
# passwd recordeduser
2. Relog to the system as the user you just created:
# ssh recordeduser@localhost
3. Type "yes" when the system prompts you to type yes or no to authenticate.
4. Insert the recordeduser’s password.

The system prompts a message to inform that your session is being recorded.
ATTENTION! Your session is being recorded!
5. Once you have finished recording the session, type:
# exit
The system logs out from the user and closes the connection with the localhost.
As a result, the user session is recorded, stored and you can play it using a journal.
Verification steps
To view your recorded session in the journal, do the following steps:
1. Run the command below:
# journalctl -o verbose -r
2. Search for the MESSAGE field of thetlog-rec recorded journal entry.
# journalctl -xel _EXE=/usr/bin/tlog-rec-session
19.6. WATCHING A RECORDED SESSION USING THE CLI

You can play a user session recording from a journal using the command-line interface (CLI).
Prerequisites
You have recorded a user session. See Recording a session using the deployed tlog system
role in the CLI .
Procedure
114
1. On the CLI terminal, play the user session recording:
# journalctl -o verbose -r
2. Search for the tlog recording:
$ /tlog-rec
You can see details such as:
The username for the user session recording
The out_txt field, a raw output encode of the recorded session
The identifier number TLOG_REC=ID_number
3. Copy the identifier number TLOG_REC=ID_number.
4. Playback the recording using the identifier number TLOG_REC=ID_number.
# tlog-play -r journal -M TLOG_REC=ID_number
As a result, you can see the user session recording terminal output being played back.
115
CHAPTER 20. CONFIGURING A HIGH-AVAILABILITY CLUSTER

USING SYSTEM ROLES
With the ha_cluster system role, you can configure and manage a high-availability cluster that uses
the Pacemaker high availability cluster resource manager.
NOTE
The High Availability Cluster (HA Cluster) role is available as a Technology Preview.
The HA system role does not currently support constraints. Running the role after
constraints are configured manually will remove the constraints, as well as any
configuration not supported by the role.
The HA system role does not currently support SBD.
20.1. HA_CLUSTER SYSTEM ROLE VARIABLES

In an ha_cluster system role playbook, you define the variables for a high availability cluster
according to the requirements of your cluster deployment.
The variables you can set for an ha_cluster system role are as follows.
ha_cluster_enable_repos
A boolean flag that enables the repositories containing the packages that are needed by the
ha_cluster system role. When this is set toyes, the default value of this variable, you must have
active subscription coverage for RHEL and the RHEL High Availability Add-On on the systems
that you will use as your cluster members or the system role will fail.
ha_cluster_cluster_present
A boolean flag which, if set to yes, determines that HA cluster will be configured on the hosts
according to the variables passed to the role. Any cluster configuration not specified in the role
and not supported by the role will be lost.
If ha_cluster_cluster_present is set to no, all HA cluster configuration will be removed from the
target hosts.
The default value of this variable is yes.
The following example playbook removes all cluster configuration on node1 and node2
- hosts: node1 node2

vars:
ha_cluster_cluster_present: no
roles:
- rhel-system-roles.ha_cluster
ha_cluster_start_on_boot
A boolean flag that determines whether cluster services will be configured to start on boot. The
default value of this variable is yes.
ha_cluster_fence_agent_packages
List of fence agent packages to install. The default value of this variable is fence-agents-all,
fence-virt.
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CHAPTER 20. CONFIGURING A HIGH-AVAILABILITY CLUSTER USING SYSTEM ROLES
ha_cluster_extra_packages
List of additional packages to be installed. The default value of this variable is no packages.
This variable can be used to install additional packages not installed automatically by the role,
for example custom resource agents.
It is possible to specify fence agents as members of this list. However,

ha_cluster_fence_agent_packages is the recommended role variable to use for specifying
fence agents, so that its default value is overridden.
ha_cluster_hacluster_password
A string value that specifies the password of the hacluster user. The hacluster user has full
access to a cluster. It is recommended that you vault encrypt the password, as described in
Encrypting content with Ansible Vault. There is no default password value, and this variable
must be specified.
ha_cluster_corosync_key_src
The path to Corosync authkey file, which is the authentication and encryption key for Corosync
communication. It is highly recommended that you have a unique authkey value for each cluster.
The key should be 256 bytes of random data.
If you specify a key for this variable, it is recommended that you vault encrypt the key, as
described in Encrypting content with Ansible Vault.
If no key is specified, a key already present on the nodes will be used. If nodes do not have the
same key, a key from one node will be distributed to other nodes so that all nodes have the same
key. If no node has a key, a new key will be generated and distributed to the nodes.
If this variable is set, ha_cluster_regenerate_keys is ignored for this key.
The default value of this variable is null.
ha_cluster_pacemaker_key_src
The path to the Pacemaker authkey file, which is the authentication and encryption key for
Pacemaker communication. It is highly recommended that you have a unique authkey value for
each cluster. The key should be 256 bytes of random data.
key. If no node has a key, a new key will be generated and distributed to the nodes.
ha_cluster_fence_virt_key_src
The path to the fence-virt or fence-xvm pre-shared key file, which is the location of the
authentication key for the fence-virt or fence-xvm fence agent.
key. If no node has a key, a new key will be generated and distributed to the nodes. If the
117
ha_cluster system role generates a new key in this fashion, you should copy the key to your
nodes' hypervisor to ensure that fencing works.
ha_cluster_pcsd_public_key_srcr, ha_cluster_pcsd_private_key_src
The path to the pcsd TLS certificate and private key. If this is not specified, a certificate-key
pair already present on the nodes will be used. If a certificate-key pair is not present, a random
new one will be generated.
If you specify a private key value for this variable, it is recommended that you vault encrypt the
key, as described in Encrypting content with Ansible Vault.
If these variables are set, ha_cluster_regenerate_keys is ignored for this certificate-key pair.
The default value of these variables is null.
ha_cluster_regenerate_keys
A boolean flag which, when set to yes, determines that pre-shared keys and TLS certificates will
be regenerated. For more information on when keys and certificates will be regenerated, see the
descriptions of the ha_cluster_corosync_key_src, ha_cluster_pacemaker_key_src,
ha_cluster_fence_virt_key_src, ha_cluster_pcsd_public_key_src, and
ha_cluster_pcsd_private_key_src variables.
The default value of this variable is no.
ha_cluster_pcs_permission_list
Configures permissions to manage a cluster using pcsd. The items you configure with this
variable are as follows:
type - user or group
name - user or group name
allow_list - Allowed actions for the specified user or group:
read - View cluster status and settings
write - Modify cluster settings except permissions and ACLs
grant - Modify cluster permissions and ACLs
full - Unrestricted access to a cluster including adding and removing nodes and
access to keys and certificates
The structure of the ha_cluster_pcs_permission_list variable and its default values are as
follows:
ha_cluster_pcs_permission_list:
- type: group
name: hacluster
allow_list:
- grant
- read
- write
118
ha_cluster_cluster_name
The name of the cluster. This is a string value with a default of my-cluster.
ha_cluster_cluster_properties
List of sets of cluster properties for Pacemaker cluster-wide configuration. Only one set of
cluster properties is supported.
The structure of a set of cluster properties is as follows:
ha_cluster_cluster_properties:
- attrs:
- name: property1_name
value: property1_value
- name: property2_name
value: property2_value
By default, no properties are set.
The following example playbook configures a cluster consisting of node1 and node2 and sets
the stonith-enabled and no-quorum-policy cluster properties.

vars:
ha_cluster_cluster_name: my-new-cluster
ha_cluster_hacluster_password: password
ha_cluster_cluster_properties:
- attrs:
- name: stonith-enabled
value: 'true'
- name: no-quorum-policy
value: stop
roles:
ha_cluster_resource_primitives
This variable defines pacemaker resources configured by the system role, including stonith
resources, including stonith resources. The items you can configure for each resource are as
follows:
id (mandatory) - ID of a resource.
agent (mandatory) - Name of a resource or stonith agent, for example

ocf:pacemaker:Dummy or stonith:fence_xvm. It is mandatory to specifystonith: for
stonith agents. For resource agents, it is possible to use a short name, such as Dummy,
instead of ocf:pacemaker:Dummy. However, if several agents with the same short name
are installed, the role will fail as it will be unable to decide which agent should be used.
Therefore, it is recommended that you use full names when specifying a resource agent.
instance_attrs (optional) - List of sets of the resource’s instance attributes. Currently,

only one set is supported. The exact names and values of attributes, as well as whether
they are mandatory or not, depend on the resource or stonith agent.
meta_attrs (optional) - List of sets of the resource’s meta attributes. Currently, only
one set is supported.
119
operations (optional) - List of the resource’s operations.
action (mandatory) - Operation action as defined by pacemaker and the resource or

stonith agent.
attrs (mandatory) - Operation options, at least one option must be specified.
The structure of the resource definition that you configure with the ha_cluster system role is as
follows.
- id: resource-id
agent: resource-agent
instance_attrs:
- attrs:
- name: attribute1_name
value: attribute1_value
- name: attribute2_name
value: attribute2_value
meta_attrs:
- attrs:
- name: meta_attribute1_name
value: meta_attribute1_value
- name: meta_attribute2_name
value: meta_attribute2_value
operations:
- action: operation1-action
attrs:
- name: operation1_attribute1_name
value: operation1_attribute1_value
- action: operation2-action
attrs:
By default, no resources are defined.
For an example ha_cluster system role system role playbook that includes resource
configuration, see Configuring a high availability cluster with fencing and resources.
ha_cluster_resource_groups
This variable defines pacemaker resource groups configured by the system role. The items you
can configure for each resource group are as follows:
id (mandatory) - ID of a group.
resources (mandatory) - List of the group’s resources. Each resource is referenced by

its ID and the resources must be defined in the ha_cluster_resource_primitives variable.
At least one resource must be listed.
meta_attrs (optional) - List of sets of the group’s meta attributes. Currently, only one
set is supported.
120
The structure of the resource group definition that you configure with the ha_cluster system
role is as follows.
ha_cluster_resource_groups:
- id: group-id
resource_ids:
- resource1-id
- resource2-id
meta_attrs:
- attrs:
- name: group_meta_attribute1_name
value: group_meta_attribute1_value
- name: group_meta_attribute2_name
value: group_meta_attribute2_value
By default, no resource groups are defined.
For an example ha_cluster system role system role playbook that includes resource group
ha_cluster_resource_clones
This variable defines pacemaker resource clones configured by the system role. The items you
can configure for a resource clone are as follows:
resource_id (mandatory) - Resource to be cloned. The resource must be defined in the

ha_cluster_resource_primitives variable or the ha_cluster_resource_groups variable.
promotable (optional) - Indicates whether the resource clone to be created is a

promotable clone, indicated as yes or no.
id (optional) - Custom ID of the clone. If no ID is specified, it will be generated. A

warning will be displayed if this option is not supported by the cluster.
meta_attrs (optional) - List of sets of the clone’s meta attributes. Currently, only one
set is supported.
The structure of the resource clone definition that you configure with the ha_cluster system role
is as follows.
ha_cluster_resource_clones:
- resource_id: resource-to-be-cloned
promotable: yes
id: custom-clone-id
meta_attrs:
- attrs:
- name: clone_meta_attribute1_name
value: clone_meta_attribute1_value
- name: clone_meta_attribute2_name
value: clone_meta_attribute2_value
By default, no resource clones are defined.
For an example ha_cluster system role system role playbook that includes resource clone
121
20.2. SPECIFYING AN INVENTORY FOR THE HA_CLUSTER SYSTEM

ROLE
When configuring an HA cluster using the ha_cluster system role playbook, you configure the
names and addresses of the nodes for the cluster in an inventory.
For each node in an inventory, you can optionally specify the following items:
node_name - the name of a node in a cluster.
pcs_address - an address used bypcs to communicate with the node. It can be a name,
FQDN or an IP address and it can include a port number.
corosync_addresses - list of addresses used by Corosync. All nodes which form a

particular cluster must have the same number of addresses and the order of the addresses
matters.
The following example shows an inventory with targets node1 and node2. node1 and node2 must be
either fully qualified domain names or must otherwise be able to connect to the nodes as when, for
example, the names are resolvable through the /etc/hosts file.
all:
hosts:
node1:
ha_cluster:
node_name: node-A
pcs_address: node1-address
corosync_addresses:
- 192.168.1.11
- 192.168.2.11
node2:
ha_cluster:
node_name: node-B
pcs_address: node2-address:2224
corosync_addresses:
- 192.168.1.12
- 192.168.2.12
20.3. CONFIGURING A HIGH AVAILABILITY CLUSTER RUNNING NO

RESOURCES
The following procedure uses the ha_cluster system role, to create a high availability cluster with
no fencing configured and which runs no resources.
Prerequisites
You have Red Hat Ansible Engine installed on the node from which you want to run the
playbook.
NOTE
You do not have to have Ansible installed on the cluster member nodes.
122
run the playbook.
RHEL System Roles.
The systems running RHEL that you will use as your cluster members must have active
subscription coverage for RHEL and the RHEL High Availability Add-On.
NOTE
The ha_cluster system role replaces any existing cluster configuration on the
specified nodes. Any settings not specified in the role will be lost.
Procedure
1. Create an inventory file specifying the nodes in the cluster, as described in Specifying an
inventory for the ha_cluster system role .
2. Create a playbook file, for example new-cluster.yml.

The following example playbook file configures a cluster with no fencing configured and
which runs no resources. When creating your playbook file for production, it is
recommended that you vault encrypt the password, as described in Encrypting content with
Ansible Vault.

vars:
roles:
3. Save the file.
$ ansible-playbook -i inventory new-cluster.yml
20.4. CONFIGURING A HIGH AVAILABILITY CLUSTER WITH FENCING

AND RESOURCES
The following procedure uses the ha_cluster system role to create a high availability cluster that
includes a fencing device, cluster resources, resource groups, and a cloned resource.
Prerequisites
playbook.
NOTE
You do not have to have Ansible Engine installed on the cluster member
nodes.
123
run the playbook.
RHEL System Roles.
NOTE
Procedure
2. Create a playbook file, for example new-cluster.yml:

The following example playbook file configures a cluster that includes fencing, several
resources, and a resource group. It also includes a resource clone for the resource group.
When creating your playbook file for production, it is recommended that you vault encrypt
the password, as described in Encrypting content with Ansible Vault.

vars:
ha_cluster_resource_primitives:
- id: xvm-fencing
agent: 'stonith:fence_xvm'
instance_attrs:
- attrs:
- name: pcmk_host_list
value: node1 node2
- id: simple-resource
agent: 'ocf:pacemaker:Dummy'
- id: resource-with-options
instance_attrs:
- attrs:
- name: fake
value: fake-value
- name: passwd
value: passwd-value
meta_attrs:
- attrs:
- name: target-role
value: Started
- name: is-managed
value: 'true'
operations:
- action: start
attrs:
- name: timeout
124
value: '30s'
- action: monitor
attrs:
- name: timeout
value: '5'
- name: interval
value: '1min'
- id: dummy-1
- id: dummy-2
- id: dummy-3
- id: simple-clone
- id: clone-with-options
- id: simple-group
resource_ids:
- dummy-1
- dummy-2
meta_attrs:
- attrs:
- name: target-role
value: Started
- name: is-managed
value: 'true'
- id: cloned-group
resource_ids:
- dummy-3
ha_cluster_resource_clones:
- resource_id: simple-clone
- resource_id: clone-with-options
promotable: yes
id: custom-clone-id
meta_attrs:
- attrs:
- name: clone-max
value: '2'
- name: clone-node-max
value: '1'
- resource_id: cloned-group
promotable: yes
roles:
3. Save the file.
$ ansible-playbook -i inventory new-cluster.yml
20.5. CONFIGURING AN APACHE HTTP SERVER IN A HIGH

125
20.5. CONFIGURING AN APACHE HTTP SERVER IN A HIGH

AVAILABILITY CLUSTER WITH THE HA_CLUSTER SYSTEM ROLE
This procedure configures an active/passive Apache HTTP server in a two-node Red Hat Enterprise
Linux High Availability Add-On cluster using the ha_cluster system role.
Prerequisites
playbook.
NOTE
You do not have to have Ansible Engine installed on the cluster member
nodes.
run the playbook.
RHEL System Roles.
Your system includes a public virtual IP address, required for Apache.
Your system includes shared storage for the nodes in the cluster, using iSCSI, Fibre
Channel, or other shared network block device.
You have configured an LVM logical volume with an ext4 files system, as described in
Configuring an LVM volume with an ext4 file system in a Pacemaker cluster.
You have configured an Apache HTTP server, as described in Configuring an Apache HTTP
Server.
Your system includes an APC power switch that will be used to fence the cluster nodes.
NOTE
Procedure
2. Create a playbook file, for example http-cluster.yml:

The following example playbook file configures a previously-created Apache HTTP server
in an active/passive two-node HA cluster
This example uses an APC power switch with a host name of zapc.example.com. If the
cluster does not use any other fence agents, you can optionally list only the fence agents
your cluster requires when defining the ha_cluster_fence_agent_packages variable, as in
this example.
126
When creating your playbook file for production, it is recommended that you vault encrypt
the password, as described in Encrypting content with Ansible Vault.
- hosts: z1.example.com z2.example.com

roles:
vars:
ha_cluster_cluster_name: my_cluster
ha_cluster_fence_agent_packages:
- fence-agents-apc-snmp
ha_cluster_resource_primitives:
- id: myapc
agent: stonith:fence_apc_snmp
instance_attrs:
- attrs:
- name: ipaddr
value: zapc.example.com
- name: pcmk_host_map
value: z1.example.com:1;z2.example.com:2
- name: login
value: apc
- name: passwd
value: apc
- id: my_lvm
agent: ocf:heartbeat:LVM-activate
instance_attrs:
- attrs:
- name: vgname
value: my_vg
- name: vg_access_mode
value: system_id
- id: my_fs
agent: Filesystem
instance_attrs:
- attrs:
- name: device
value: /dev/my_vg/my_lv
- name: directory
value: /var/www
- name: fstype
value: ext4
- id: VirtualIP
agent: IPaddr2
instance_attrs:
- attrs:
- name: ip
value: 198.51.100.3
- name: cidr_netmask
value: 24
- id: Website
agent: apache
instance_attrs:
- attrs:
- name: configfile
value: /etc/httpd/conf/httpd.conf
127
- name: statusurl
value: http://127.0.0.1/server-status
- id: apachegroup
resource_ids:
- my_lvm
- my_fs
- VirtualIP
- Website
3. Save the file.
$ ansible-playbook -i inventory http-cluster.yml
Verification steps
1. From one of the nodes in the cluster, check the status of the cluster. Note that all four
resources are running on the same node, z1.example.com.
If you find that the resources you configured are not running, you can run the pcs resource
debug-start resource command to test the resource configuration.
[root@z1 ~]# pcs status

Cluster name: my_cluster
Last updated: Wed Jul 31 16:38:51 2013
Last change: Wed Jul 31 16:42:14 2013 via crm_attribute on z1.example.com
Stack: corosync
Current DC: z2.example.com (2) - partition with quorum
Version: 1.1.10-5.el7-9abe687
2 Nodes configured
6 Resources configured
Online: [ z1.example.com z2.example.com ]
Full list of resources:

myapc (stonith:fence_apc_snmp): Started z1.example.com
Resource Group: apachegroup
my_lvm (ocf::heartbeat:LVM): Started z1.example.com
my_fs (ocf::heartbeat:Filesystem): Started z1.example.com
VirtualIP (ocf::heartbeat:IPaddr2): Started z1.example.com
Website (ocf::heartbeat:apache): Started z1.example.com
2. Once the cluster is up and running, you can point a browser to the IP address you defined as
the IPaddr2 resource to view the sample display, consisting of the simple word "Hello".
Hello
3. To test whether the resource group running on z1.example.com fails over to node
z2.example.com, put node z1.example.com in standby mode, after which the node will no
longer be able to host resources.
[root@z1 ~]# pcs node standby z1.example.com
128
4. After putting node z1 in standby mode, check the cluster status from one of the nodes in
the cluster. Note that the resources should now all be running on z2.
[root@z1 ~]# pcs status

Cluster name: my_cluster
Last updated: Wed Jul 31 17:16:17 2013
Last change: Wed Jul 31 17:18:34 2013 via crm_attribute on z1.example.com
Stack: corosync
Current DC: z2.example.com (2) - partition with quorum
Version: 1.1.10-5.el7-9abe687
2 Nodes configured
6 Resources configured
Node z1.example.com (1): standby

Online: [ z2.example.com ]
Full list of resources:
myapc (stonith:fence_apc_snmp): Started z1.example.com

Resource Group: apachegroup
my_lvm (ocf::heartbeat:LVM): Started z2.example.com
my_fs (ocf::heartbeat:Filesystem): Started z2.example.com
VirtualIP (ocf::heartbeat:IPaddr2): Started z2.example.com
Website (ocf::heartbeat:apache): Started z2.example.com
The web site at the defined IP address should still display, without interruption.
5. To remove z1 from standby mode, enter the following command.
[root@z1 ~]# pcs node unstandby z1.example.com
NOTE
Removing a node from standby mode does not in itself cause the resources
to fail back over to that node. This will depend on the resource-stickiness
value for the resources. For information on the resource-stickiness meta
attribute, see Configuring a resource to prefer its current node.


RHEL System Roles KB article
The ansible-playbook(1) man page.
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Red Hat Enterprise Linux 8

Administration and configuration tasks using

Last Updated: 2022-01-26

Java ® is a registered trademark of Oracle and/or its affiliates.

All other trademarks are the property of their respective owners.

9.2. CONFIGURING OPENSSH SERVERS USING THE SSHD SYSTEM ROLE 55

15.17. ADDITIONAL RESOURCES 95

MAKING OPEN SOURCE MORE INCLUSIVE

PROVIDING FEEDBACK ON RED HAT DOCUMENTATION

For simple comments on specific passages:

4. Follow the displayed instructions.

For submitting more complex feedback, create a Bugzilla ticket:

1. Go to the Bugzilla website.

2. As the Component, use Documentation.

4. Click Submit Bug.

CHAPTER 1. GETTING STARTED WITH RHEL SYSTEM ROLES

1.1. INTRODUCTION TO RHEL SYSTEM ROLES

nbde_client and nbde_server

Red Hat Enterprise Linux (RHEL) System Roles

/usr/share/doc/rhel-system-roles documentation [1]

Introduction to the SELinux system role

Introduction to the storage role

Administration and configuration tasks using System Roles in RHEL

1.2. RHEL SYSTEM ROLES TERMINOLOGY

System Roles terminology

1.3. APPLYING A ROLE

# yum install rhel-system-roles

1. Enable the RHEL Ansible Engine repository:

2. Install Ansible Engine:

# yum install ansible

Ensure that you are able to create an Ansible inventory.

Ensure that you are able to create an Ansible playbook.

Playbooks are human-readable, and are defined in the yaml format.

# ansible-playbook -i name.of.the.inventory name.of.the.playbook

Specify all hosts when executing the ansible-playbook command:

# ansible-playbook -i host1,host2,... name.of.the.playbook

Ansible Playbook | example-playbook.yml:

- hosts: "{{ target_host }}"

Playbook execution command:

# ansible-playbook -i host1,..hostn -e target_host=host5 example-

Using roles in Ansible playbook

Examples of Ansible playbooks

How to create and work with inventory?

1.4. ADDITIONAL RESOURCES

Managing local storage using RHEL System Roles

[1] This documentation is installed automatically with the rhel-system-roles package.

CHAPTER 2. INSTALLING RHEL SYSTEM ROLES IN YOUR

# yum install rhel-system-roles

a. Enable the RHEL Ansible Engine repository:

# subscription-manager repos --enable ansible-2-for-rhel-8-x86_64-rpms

b. Install Ansible Engine:

# yum install ansible

As a result, you are able to create an Ansible playbook.

The Red Hat Enterprise Linux (RHEL) System Roles

The ansible-playbook man page.

CHAPTER 3. INSTALLING AND USING COLLECTIONS

3.1. INTRODUCTION TO ANSIBLE COLLECTIONS

3.2. COLLECTIONS STRUCTURE

playbooks/: playbooks are available here