Upgrading SAP environments from RHEL 8 to RHEL 9

Procedure

1. Complete system-specific setup.

   1. Prepare non-cloud or BYOS cloud systems by executing the following steps:
      

      1. If you previously performed an in-place upgrade from RHEL 7 to RHEL 8, remove the /root/tmp_leapp_py3 directory if it is present on your system:

         # rm -rf /root/tmp_leapp_py3

      2. Register and subscribe the system to a Red Hat repository source. If you are using Red Hat Satellite, make sure that both RHEL 8 and RHEL 9 e4s repositories are available and synchronized with the latest updates. Enable the following repos for the activation key:

         rhel-8-for-x86_64-baseos-e4s-rpms
         rhel-8-for-x86_64-appstream-e4s-rpms
         rhel-8-for-x86_64-sap-netweaver-e4s-rpms
         rhel-8-for-x86_64-sap-solutions-e4s-rpms
         rhel-9-for-x86_64-baseos-e4s-rpms
         rhel-9-for-x86_64-appstream-e4s-rpms
         rhel-9-for-x86_64-sap-netweaver-e4s-rpms
         rhel-9-for-x86_64-sap-solutions-e4s-rpms

      3. Check and confirm that your RHEL 8 system has the e4s repositories enabled:

         # subscription-manager repos --disable='*' \
         --enable="rhel-8-for-x86_64-baseos-e4s-rpms" \
         --enable="rhel-8-for-x86_64-appstream-e4s-rpms" \
         --enable="rhel-8-for-x86_64-sap-solutions-e4s-rpms" \
         --enable="rhel-8-for-x86_64-sap-netweaver-e4s-rpms"

      4. Remove all files cached by yum/dnf:

         # rm -rf /var/cache/yum

      5. Make sure that the RHEL release lock is set to the desired source OS version, for example, 8.6:

         # subscription-manager release --set=8.6
         Release set to: 8.6

   2. Make sure that the RHEL release lock is set to the desired source OS version, for example 8.6, on PAYG cloud instances on AWS, Microsoft Azure or Google Cloud:

      # rhui-set-release --set 8.6

      If rhui-set-release is not available on your cloud provider, run:

      # echo 8.6 > /etc/yum/vars/releasever

   3. Prepare PAYG cloud instances on AWS by installing the leapp-rhui-aws-sap-e4s package, which provides RHEL 9 e4s repositories to your AWS cloud instance:

      # dnf install leapp-rhui-aws-sap-e4s

   4. Prepare PAYG cloud instances on Google Cloud by downloading and installing the leapp-rhui-google-v1-rhel8-sap package, which provides RHEL 9 e4s repositories to your Google cloud instance, as instructed in Leapp RHUI packages for Google Cloud Platform (GCP).
      

   5. Prepare PAYG cloud instances on Microsoft Azure by installing the leapp-rhui-azure-sap package, which provides RHEL 8 e4s repositories to your Microsoft Azure cloud instance:

      dnf install leapp-rhui-azure-sap

2. After completing the above steps, perform the remaining steps on all systems, no matter if your system is a non-cloud, BYOS cloud, or PAYG cloud system on AWS, Google Cloud or Microsoft Azure.
   

   1. Stop the SAP HANA system(s) and stop all SAP processes.

      Important

      Do not unmount the SAP HANA file systems, as these are required for detecting if SAP HANA is installed and the version of the installed system.

   2. If your system is configured to start SAP processes automatically at boot time, disable the automatic start of SAP processes.
      

   3. Verify that the RHEL settings for SAP HANA are in place by checking the following:
      

      1. As per SAP note 2772999, the following parameter is required for SAP applications including SAP HANA and is typically set in file /etc/sysctl.d/sap.conf:

         vm.max_map_count = 2147483647

         The same setting is required for SAP applications including SAP HANA on RHEL 9.
         The file /etc/sysctl.d/sap.conf might also contain:

         kernel.pid_max = 4194304

      2. All other settings for SAP HANA (in file /etc/sysctl.conf and /etc/sysctl.d/sap_hana.conf) are identical for RHEL 8 and RHEL 9 and must be left in place. For more details refer to SAP Notes 2382421.
         

   4. Update your RHEL 8.* system to the desired source OS version package levels:

      # dnf update

   5. Reboot the system:

      # reboot

   6. After the system is up and running, check and confirm that no SAP HANA systems and no SAP processes are running on the system.
      
   7. Make sure the SAP HANA file systems are available.
      

   8. Install the leapp utility:

      # dnf install leapp-upgrade

   9. Temporarily disable any antivirus software.
      
   10. Ensure there is no configuration management system (such as Salt, Chef, Puppet, Ansible) enabled or configured to attempt to restore the original RHEL 8 system.
       
   11. Ensure your system does not use any Network Interface Card (NIC) with a name based on the prefix 'eth'. Refer to this KB article for more information.
       
   12. If your NSS (Network Security Services) database was created in RHEL 7 or earlier, verify that the database has been converted from the DBM database format to SQLite. For more information, see Updating NSS databases from DBM to SQLite.
       
   13. RHEL 9 does not support the legacy network-scripts package that was deprecated in RHEL 8. Before you upgrade, move your custom network scripts and write a NetworkManager dispatcher script that executes your existing custom scripts. For more information, see Migrating custom network scripts to NetworkManager dispatcher scripts.
       
   14. Make sure that you have a full backup or a virtual machine snapshot of your system.
       
   15. If not done already, perform a restore test of the backup to another system, to make sure that the backup can be used for a successful restore. A restore test is also useful for getting used to the required restore activities so that you can get a working system back as quickly as possible if necessary.

Procedure

1. Perform the pre-upgrade assessment:

   • On a non-cloud or BYOS cloud system, run:

     # leapp preupgrade --channel e4s

   • On a PAYG cloud instance on AWS, Google Cloud or Microsoft Azure, run:

     # leapp preupgrade --no-rhsm --channel e4s

2. If any inhibitors are reported, the output file /var/log/leapp/leapp-report.txt contains all necessary information, including remediation steps, to avoid these inhibitors.
3. Manually resolve all the reported problems before proceeding with the in-place upgrade. As mentioned before, you can repeat this step as often as necessary until no more inhibitors are reported.

Procedure

1. Before performing the upgrade, back up all of your data to avoid potential data loss if you have not done so already.
   
2. Perform a restore test to verify that the last backup was successful.
   
3. Check and confirm again that no SAP HANA system and no SAP processes are running on the system.
   
4. Check and confirm that the SAP HANA file systems are mounted, as a certain file located below this path is used by Leapp to detect the SAP HANA version when upgrading to RHEL 9.
   
5. Check and confirm that your SAP HANA system will not be started automatically at boot time. For more information, please refer to SAP note 2315907 - Starting HANA automatically after Host has been started.
   

6. Run the upgrade process:

   • On a non-cloud or BYOS cloud system, run:

     # leapp upgrade --channel e4s

   • On a PAYG cloud instance on AWS, Google Cloud or Microsoft Azure, run

     # leapp upgrade --no-rhsm --channel e4s

7. After the completion of this command, a message appears which asks you to reboot the system. Reboot the system now so that it can finish the upgrade:
   

   # reboot

8. The system boots into a RHEL 9-based initial RAM disk image (initramfs), upgrades all packages, and reboots again. This might take some time. Once all packages have been upgraded, the system automatically reboots into the RHEL 9 system.

Procedure

1. Verify that the current OS version is Red Hat Enterprise Linux 9. For example, for the upgrade from RHEL 8.8 to RHEL 9.2:

   # cat /etc/redhat-release
   Red Hat Enterprise Linux release 9.2 (Plow)

2. Verify that the RHEL release lock is set to the desired target OS version. For example, for the upgrade from RHEL 8.8 to RHEL 9.2:

   • On a non-cloud or BYOS cloud system:

     Make sure that the RHEL release lock is set to 9.2 and that all lines in /etc/yum.repos.d/redhat.repo starting with baseurl contain the string rhel9/9.2(and not for example rhel9/8.8), in the URL field. Run:

     # subscription-manager release --set=9.2
     Release set to: 9.2

   • On a PAYG cloud instance on AWS, Google Cloud or Azure, run:

     # cat /etc/dnf/vars/releasever
     9.2

3. Verify that the system has all necessary repos enabled:

   # dnf repolist

   • On a non-cloud or BYOS cloud system, the output should contain:

     rhel-9-for-x86_64-appstream-e4s-rpms
     rhel-9-for-x86_64-baseos-e4s-rpms
     rhel-9-for-x86_64-sap-netweaver-e4s-rpms
     rhel-9-for-x86_64-sap-solutions-e4s-rpms

     Disable all normal (=non-e4s) repos. Run the following command:

     # subscription-manager repos \
     --disable="*" \
     --enable="rhel-9-for-x86_64-baseos-e4s-rpms" \
     --enable="rhel-9-for-x86_64-appstream-e4s-rpms" \
     --enable="rhel-9-for-x86_64-sap-solutions-e4s-rpms" \
     --enable="rhel-9-for-x86_64-sap-netweaver-e4s-rpms"+*

   • On a PAYG cloud instance on AWS, the output should contain:

     rhel-9-for-x86_64-appstream-e4s-rhui-rpms
     rhel-9-for-x86_64-baseos-e4s-rhui-rpms
     rhel-9-for-x86_64-highavailability-e4s-rhui-rpms
     rhel-9-for-x86_64-sap-netweaver-e4s-rhui-rpms
     rhel-9-for-x86_64-sap-solutions-e4s-rhui-rpms
     rhui-client-config-server-9-sap-bundle

   • On a PAYG cloud instance on Google Cloud, the output should contain:

     google-cloud-sdk
     google-compute-engine
     rhui-rhel-9-for-x86_64-appstream-e4s-rhui-rpms
     rhui-rhel-9-for-x86_64-baseos-e4s-rhui-rpms
     rhui-rhel-9-for-x86_64-highavailability-e4s-rhui-rpms
     rhui-rhel-9-for-x86_64-sap-netweaver-e4s-rhui-rpms
     rhui-rhel-9-for-x86_64-sap-solutions-e4s-rhui-rpms

   • On a PAYG cloud instance on Microsoft Azure, the output should contain:

     rhel-9-for-x86_64-appstream-e4s-rhui-rpms
     rhel-9-for-x86_64-baseos-e4s-rhui-rpms
     rhel-9-for-x86_64-highavailability-e4s-rhui-rpms
     rhel-9-for-x86_64-sap-netweaver-e4s-rhui-rpms
     rhel-9-for-x86_64-sap-solutions-e4s-rhui-rpms
     rhui-microsoft-azure-rhel9-sap-ha

4. Verify that network services are operational. For example, try to connect to the system using ssh.

Procedure

1. If you had configured your RHEL 8.6 system for SAP HANA using the RHEL System Roles for SAP (package rhel-system-roles-sap, roles sap_general_preconfigure and sap_hana_preconfigure) and if you have not done any additional modification to your system configuration afterwards, you can configure your system with the RHEL System Roles for SAP again.

2. In case you want or need to configure your system manually, the following steps will be required:

   1. Confirm that the Server environment group is installed:

      # dnf group list installed server+*+
      [...]
      Installed Environment Groups:
         Server

   2. Verify that the packages chkconfig and compat-openssl11 are installed:

      # dnf list installed chkconfig compat-openssl11
      [...]
      Installed Packages
      chkconfig.x86_64          1.20-2.el9         @System
      compat-openssl11.x86_64   1:1.1.1k-4.el9_0   @rhel-9-for-x86_64-appstream-e4s-rpms

      Install any of the above packages if necessary.

      Note

      Package compat-openssl11 is only required for SAP HANA scale-out installations.

   3. Verify that the service abrt-ccpp is nonexistent or disabled:

      # systemctl status abrt-ccpp
      Unit abrt-ccpp.service could not be found.

      If it exists and is not disabled, disable it:

      # systemctl disable abrt-ccpp --now

      After modifying your system configuration as described, reboot your system.

      Note

      For verifying that your system is configured according to the applicable SAP notes, you can run RHEL system roles sap_general_preconfigure and sap_hana_preconfigure in assert mode.

3. Verify that your system is running with the RHEL kernel version certified for the desired OS target version, as required in SAP note 3108302.

   # uname -r
   5.14.0-70.36.1.el9_0.x86_64