Chapter 1. Planning an upgrade
An in-place upgrade is the recommended and supported way to migrate your system to the next major version of RHEL.
You should consider the following before upgrading to RHEL 8:
Operating system - The operating system is upgraded by the
Leapputility under the following conditions:The Server variant installed of the latest available RHEL 7 version, which currently is:
- RHEL 7.9 on the 64-bit Intel, IBM POWER 8 (little endian), and IBM Z architectures
RHEL 7.6 on architectures that require kernel version 4.14: 64-bit ARM, IBM POWER 9 (little endian), or IBM Z (Structure A)
See Supported in-place upgrade paths for Red Hat Enterprise Linux for more information.
- Minimum hardware requirements for RHEL 8 met
- Access to up-to-date RHEL 7.9 and RHEL 8.2 content provided; see Preparing a RHEL 7 system for the upgrade, step 1 for details.
-
Applications - You can migrate applications installed on your system using
Leapp. However, in certain cases, you have to create custom actors, which specify actions to be performed byLeappduring the upgrade, for example, reconfiguring an application or installing a specific hardware driver. For more information, see Handling the migration of your custom and third-party applications. Note that custom actors are unsupported by Red Hat. Security - You should evaluate this aspect before the upgrade and take additional steps when the upgrade process completes. Consider especially the following:
- Before the upgrade, define the security standard your system needs to comply with and understand the security changes in RHEL 8.
-
During the upgrade process, the
Leapputility sets SELinux mode to permissive. - In-place upgrades of systems in FIPS mode are not supported.
- After the upgrade is finished, re-evaluate and re-apply your security policies. For information about applying security policies that have been disabled during the upgrade or newly introduced in RHEL 8, see Applying security policies.
- Storage and file systems - You should always back up your system prior to upgrading. For example, you can use the Relax-and-Recover (ReaR) utility, LVM snapshots, RAID splitting, or a virtual machine snapshot.
- Downtime - The upgrade process can take from several minutes to several hours.
- Satellite - If you manage your hosts through Satellite, you can upgrade multiple hosts simultaneously from RHEL 7 to RHEL 8 using the Satellite web UI. For more information, see Upgrading Hosts from RHEL 7 to RHEL 8.
- Public Clouds - The in-place upgrade is supported for on-demand instances on Amazon Web Services (AWS) and Microsoft Azure, using Red Hat Update Infrastructure (RHUI).
Known limitations - Notable known limitations of
Leappcurrently include:- Encryption of the whole disk or a partition, or file-system encryption currently cannot be used on a system targeted for an in-place upgrade.
- No network-based multipath and no kind of network storage mount can be used as a system partition (for example, iSCSI, or NFS).
- The in-place upgrade is currently unsupported for on-demand instances on the remaining Public Clouds (Huawei Cloud, Alibaba Cloud, Google Cloud) that use Red Hat Update Infrastructure but not Red Hat Subscription Manager for a RHEL subscription.
See also Known Issues.
You can use Red Hat Insights to determine which of the systems you have registered to Insights is on a supported upgrade path to RHEL 8. To do so, navigate to the respective Advisor recommendation in Insights, enable the recommendation under the Actions drop-down menu, and inspect the list under the Affected systems heading. Note that the Advisor recommendation considers only the RHEL 7 minor version and does not perform a pre-upgrade assessment of the system.