Red Hat Enterprise Linux-8-Upgrading To RHEL 8-En-US
Red Hat Enterprise Linux-8-Upgrading To RHEL 8-En-US
Red Hat Enterprise Linux-8-Upgrading To RHEL 8-En-US
Upgrading to RHEL 8
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Abstract
This document provides instructions on how to perform an in-place upgrade from Red Hat
Enterprise Linux 7 to Red Hat Enterprise Linux 8 using the Leapp utility. During the in-place
upgrade, the existing RHEL 7 operating system is replaced by a RHEL 8 version.
Table of Contents
Table of Contents
. . . . . . . . . . . . . FEEDBACK
PROVIDING . . . . . . . . . . . . ON
. . . .RED
. . . . .HAT
. . . . .DOCUMENTATION
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3. . . . . . . . . . . . .
.CHAPTER
. . . . . . . . . . 1.. .REQUIREMENTS
. . . . . . . . . . . . . . . . . AND
. . . . . .KNOWN
. . . . . . . . .LIMITATIONS
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4. . . . . . . . . . . . .
1.1. REQUIREMENTS 4
1.2. KNOWN LIMITATIONS 4
.CHAPTER
. . . . . . . . . . 2.
. . PREPARING
.............A
. . RHEL
. . . . . . .7. SYSTEM
. . . . . . . . . .FOR
. . . . .THE
. . . . UPGRADE
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6. . . . . . . . . . . . .
Prerequisites 6
Procedure 6
.CHAPTER
. . . . . . . . . . 3.
. . PERFORMING
. . . . . . . . . . . . . . . .THE
. . . . UPGRADE
. . . . . . . . . . . FROM
. . . . . . . RHEL
. . . . . . .7. TO
. . . .RHEL
. . . . . .8. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8. . . . . . . . . . . . .
Prerequisites 8
Procedure 8
.CHAPTER
. . . . . . . . . . 4.
. . .VERIFYING
. . . . . . . . . . . .THE
. . . . POST-UPGRADE
. . . . . . . . . . . . . . . . . . STATE
. . . . . . . .OF
. . . THE
. . . . . RHEL
. . . . . .8
. . SYSTEM
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
..............
Prerequisites 10
Procedure 10
. . . . . . . . . . . 5.
CHAPTER . . TROUBLESHOOTING
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .11. . . . . . . . . . . . .
5.1. TROUBLESHOOTING RESOURCES 11
Console output 11
Logs 11
Reports 11
5.2. TROUBLESHOOTING TIPS 11
Pre-upgrade phase 11
initramfs phase 11
Post-upgrade phase 12
5.3. KNOWN ISSUES 12
5.4. OBTAINING SUPPORT 12
. . . . . . . . . . . 6.
CHAPTER . . .RELATED
. . . . . . . . . .INFORMATION
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
..............
1
Red Hat Enterprise Linux 8 Upgrading to RHEL 8
2
PROVIDING FEEDBACK ON RED HAT DOCUMENTATION
For simple comments on specific passages, make sure you are viewing the documentation in the
Multi-page HTML format. Highlight the part of text that you want to comment on. Then, click
the Add Feedback pop-up that appears below the highlighted text, and follow the displayed
instructions.
3. Fill in the Description field with your suggestion for improvement. Include a link to the
relevant part(s) of documentation.
3
Red Hat Enterprise Linux 8 Upgrading to RHEL 8
1.1. REQUIREMENTS
An in-place upgrade to RHEL 8 is currently supported only on systems meeting the following
requirements:
At least 100MB of free space available on the boot partition (mounted at /boot)
FIPS mode disabled; see the solution How to disable FIPS mode in RHEL 6 or RHEL 7
Minimum hardware requirements for RHEL 8; see Red Hat Enterprise Linux technology
capabilities and limits
The system registered to the Red Hat Content Delivery Network or Red Hat Satellite 6.5 or
later using the Red Hat Subscription Manager
A rollback to the last known good state has not been implemented in the Leapp utility. A
complete system backup prior to the upgrade is recommended, for example, by using the
Relax-and-Recover (ReaR) utility. For more information, see the ReaR documentation and
What is Relax and Recover (ReaR) and how can I use it for disaster recovery? .
Packages that are not a part of the Minimal (@minimal) or Base (@base) package groups
might cause the upgrade to fail.
No disk, LVM, or file-system encryption can currently be used on a system targeted for an in-
place upgrade.
No Multipath or any kind of network storage mount can be used as a system partition (for
example, iSCSI, FCoE, or NFS).
During the upgrade process, the Leapp utility sets SELinux mode to permissive and disables
firewall.
No support for other Red Hat products running on top of the OS, Red Hat Software Collections,
Red Hat Developer Tools, or add-ons, such as High Availability or Network Function
Virtualization, is currently provided.
On systems where the root file system is formatted as XFS with ftype=0 (default in RHEL 7.2
and earlier versions), the RPM upgrade transaction calculation might fail if numerous packages
are installed on the system. If the cause of such a failure is insufficient space, increase the
available space by using the LEAPP_OVL_SIZE=<SIZE_IN_MB> environment variable with the
leapp upgrade command, and set the size to more than 2048 MB (see a related solution for
more information). To determine the ftype value, use the xfs_info command.
The whole system must be mounted under the root file system, with the exception of /home
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CHAPTER 1. REQUIREMENTS AND KNOWN LIMITATIONS
The whole system must be mounted under the root file system, with the exception of /home
and /boot. For example, the /var or /usr directories cannot be mounted on a separate partition.
The in-place upgrade is currently unsupported for on-demand instances on Public Clouds
(Amazon EC2, Azure, Huawei Cloud, Alibaba Cloud, Google Cloud) that use Red Hat Update
Infrastructure but not Red Hat Subscription Manager for a RHEL subscription.
5
Red Hat Enterprise Linux 8 Upgrading to RHEL 8
Prerequisites
The system meets conditions listed in Chapter 1, Requirements and known limitations .
Procedure
1. Make sure your system has been successfully registered to the Red Hat Content Delivery
Network (CDN) or Red Hat Satellite 6.5 or later using the Red Hat Subscription Manager.
NOTE
2. Verify that you have the Red Hat Enterprise Linux Server subscription attached.
3. If you use the yum-plugin-versionlock plug-in to lock packages to a specific version, clear the
lock by running:
See How to restrict yum to install or upgrade a package to a fixed specific package version? for
more information.
4. Set the Red Hat Subscription Manager to consume the RHEL 7.6 content:
NOTE
The upgrade is designed for RHEL 7.6 as a starting point. If you have any
packages from a later version of RHEL, please downgrade them to their RHEL 7.6
versions.
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CHAPTER 2. PREPARING A RHEL 7 SYSTEM FOR THE UPGRADE
# yum update
# reboot
7. Enable the Extras repository where some of the dependencies are available:
9. Download additional required data files (RPM package changes and RPM repository mapping)
attached to the Knowledgebase article Data required by the Leapp utility for an in-place
upgrade from RHEL 7 to RHEL 8 and place them in the /etc/leapp/files/ directory.
10. Make sure you have any configuration management (such as Salt, Chef, Puppet, Ansible)
disabled or adequately reconfigured to not attempt to restore the original RHEL 7 system.
11. Make sure your system does not use more than one Network Interface Card (NIC) with a name
based on the prefix used by the kernel (eth). For instructions on how to migrate to another
naming scheme before an in-place upgrade to RHEL 8, see How to perform an in-place
upgrade to RHEL 8 when using kernel NIC names on RHEL 7.
12. Make sure you have a full system backup or a virtual machine snapshot. You should be able to
get your system to the pre-upgrade state if you follow standard disaster recovery procedures
within your environment.
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Red Hat Enterprise Linux 8 Upgrading to RHEL 8
Prerequisites
The steps listed in Chapter 2, Preparing a RHEL 7 system for the upgrade have been completed,
including a full system backup.
Procedure
1. On your RHEL 7 system, start the upgrade process:
# leapp upgrade
In this phase, the Leapp utility collects data about your system, checks the upgradability, and
produces a pre-upgrade report in the /var/log/leapp/leapp-report.txt file.
If the system is upgradable, Leapp downloads necessary data and prepares an RPM transaction
for the upgrade.
If your system does not meet the parameters for a reliable upgrade, Leapp terminates the
upgrade process and provides a record describing the issue and a recommended solution in the
/var/log/leapp/leapp-report.txt file. For more information, see Chapter 5, Troubleshooting.
# reboot
In this phase, the system boots into an RHEL 8-based initial RAM disk image, initramfs. Leapp
upgrades all packages and automatically reboots to the RHEL 8 system.
Ensure that there are no SELinux denials before you switch from permissive mode, for
example, by using the ausearch utility. See Chapter 5, Troubleshooting for more details.
# setenforce 1
c. Enable firewall:
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CHAPTER 3. PERFORMING THE UPGRADE FROM RHEL 7 TO RHEL 8
d. Unset the RHEL 7.6 version to be able to consume yum updates for RHEL 8 correctly:
e. Verify the state of the system as described in Chapter 4, Verifying the post-upgrade state
of the RHEL 8 system.
9
Red Hat Enterprise Linux 8 Upgrading to RHEL 8
Prerequisites
The system has been upgraded following the steps described in Chapter 3, Performing the
upgrade from RHEL 7 to RHEL 8 and you were able to log in to RHEL 8.
Procedure
After the upgrade completes, determine whether the system is in the required state, at least:
# cat /etc/redhat-release
Red Hat Enterprise Linux release 8.0 (Ootpa)
# uname -r
4.18.0-80.el8.x86_64
Verify that network services are operational, for example, try to connect to a server using SSH.
10
CHAPTER 5. TROUBLESHOOTING
CHAPTER 5. TROUBLESHOOTING
This chapter lists troubleshooting resources and tips.
In verbose mode, Leapp prints info, warning, error, and critical messages.
In debug mode, Leapp prints debug, info, warning, error, and critical messages.
Logs
The /var/log/leapp/leapp-upgrade.log file lists issues found during the initramfs phase.
Reports
The /var/log/leapp/leapp-report.txt file lists issues found during the pre-upgrade phase.
Verify that your system meets all conditions listed in Chapter 1, Requirements and known
limitations. For example, use the df -h command to see whether the system has sufficient
available space in the /boot partition.
Make sure you have followed all steps described in Chapter 2, Preparing a RHEL 7 system for
the upgrade, for example, your system does not use more than one Network Interface Card
(NIC) with a name based on the prefix used by the kernel (eth).
If a problem occurs during downloading RPM packages, examine transaction debug data located
in the /var/log/leapp/dnf-debugdata/ directory.
initramfs phase
During this phase, potential failures redirect you into the dracut shell. Check the journal:
# journalctl
Alternatively, restart the system from the dracut shell using the reboot command and check the
/var/log/leapp/leapp-upgrade.log file.
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Red Hat Enterprise Linux 8 Upgrading to RHEL 8
Post-upgrade phase
If your system seems to be successfully upgraded but booted with the old RHEL 7 kernel, restart
the system and check the kernel version of the default entry in GRUB.
Make sure you have followed the recommended steps in Chapter 4, Verifying the post-upgrade
state of the RHEL 8 system.
If your application or a service stops working or behaves incorrectly after you have switched
SELinux to enforcing mode, search for denials using the ausearch, journalctl, or dmesg utilities:
The most common problems are caused by incorrect labeling. See Troubleshooting problems
related to SELinux for more details.
It is safe to ignore such messages, which neither interrupt nor affect the result of the upgrade
process.
Network teaming currently does not work when the in-place upgrade is performed while
Network Manager is disabled or not installed. (BZ#1717330)
The Leapp utility currently fails to upgrade packages from the Supplementary channel, such as
the virtio-win package, due to missing mapping support for this channel. (BZ#1621775)
RHEL 8 packages that use RPM rich dependencies cause failure during the upgrade transaction
check. So far, redhat-rpm-config with its dependencies and tpm2-abrmd have been identified
to cause such a problem. These packages are removed during the upgrade process by Leapp.
If you use an HTTP proxy, Red Hat Subscription Manager must be configured to use such a
proxy, or the subscription-manager command must be executed with the --proxy
<hostname> option. Otherwise, an execution of the subscription-manager command fails. If
you use the --proxy option instead of the configuration change, the upgrade process fails
because Leapp is unable to detect the proxy. To prevent this problem from occurring, manually
edit the rhsm.conf file as described in How to configure HTTP Proxy for Red Hat Subscription
Management. (BZ#1689294).
If your RHEL 7 system is installed on an FCoE Logical Unit Number (LUN) and connected to a
network card that uses the bnx2fc driver, the LUN is not detected in RHEL 8 after the upgrade.
Consequently, the upgraded system fails to boot. (BZ#1718147)
To open a support case, select RHEL 8 as the product, and provide a sosreport from your system. To
12
CHAPTER 5. TROUBLESHOOTING
To open a support case, select RHEL 8 as the product, and provide a sosreport from your system. To
generate a sosreport on your system, run:
# sosreport
For details on generating a sosreport, see the solution What is a sosreport and how to create one in Red
Hat Enterprise Linux 4.6 and later?.
For more information on opening and managing a support case on the Customer Portal, see the article
How do I open and manage a support case on the Customer Portal? .
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Red Hat Enterprise Linux 8 Upgrading to RHEL 8
14