Chapter 1. Planning an upgrade
An in-place upgrade is the recommended and supported way to upgrade 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
Leapp
utility 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: IBM POWER 9 (little endian) or IBM Z (Structure A)
RHEL 7.7 when on SAP HANA on the 64-bit Intel architecture
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 byLeapp
during 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
Leapp
utility 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.
- SAP HANA - If you are using SAP HANA, follow How to in-place upgrade SAP environments from RHEL 7 to RHEL 8 instead. Note that the upgrade path for RHEL with SAP HANA might differ.
- 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
Leapp
currently 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.