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Guidelines for upgrading the ONTAP Mediator in a MetroCluster configuration

If you are upgrading the ONTAP Mediator you must meet the Linux version requirements and follow guidelines for the upgrade.

  • The Mediator service can be upgraded from version 1.0 to 1.1.

  • All Mediator versions are supported on MetroCluster IP configurations running ONTAP 9.7 or later.

Upgrading the host operating system and Mediator together​

The following table provides the upgrade guidelines if you are upgrading from RHEL/CentOS 7.6 to a later RHEL/CentOS release in addition upgrading the Mediator version.

Target Linux versionTarget Mediator versionUpgrade notes
RHEL/CentOS 7.71.1

  • The upgrade must be performed in the following order:

    1. Upgrade the operating system from RHEL/CentOS version 7.6 to 7.7.

      Note
      The ONTAP Mediator and Mediator-assisted automatic unplanned switchover is not available during the operating system upgrade. The Mediator is offline until the Mediator version 1.0 to 1.1 upgrade process is complete.
    2. Reboot the host to apply the kernel module changes.
    3. Upgrade the Mediator from version 1.0 to 1.1.

      Installing or upgrading the ONTAP Mediator service

  • The storage iscsi-initiator show command will report that the connection to the Mediator service is down during the upgrade.

  • The ONTAP operating system will generate cf.mccip.med.auso.stDisabled EMS events during the upgrade.

  • The ONTAP operating system will generate a cf.mccip.med.auso.stEnabled EMS event when automatic unplanned switchover is re-enabled.

RHEL/CentOS 8.0 or 8.11.1There is no direct upgrade path. You must remove the 1.0 version and install the 1.1 version after the operating system upgrade:

  1. Delete the Mediator service from the ONTAP configuration: metrocluster configuration-settings mediator remove

  2. Uninstall the 1.0 version of the Mediator service.

    Uninstalling the ONTAP Mediator service

  3. Upgrade the Linux operating system to version 8.0 or 8.1.

  4. Install the 1.1 version of the Mediator service.

    Installing or upgrading the ONTAP Mediator service

  5. Add the Mediator service to the ONTAP configuration: metrocluster configuration-settings add -addressmediator-1.1-ip-address

After the upgrade​

After the Mediator and operating system upgrade is complete, you should issue the storage iscsi-initiator show command to confirm that the Mediator connections are up.

Reverting from a Mediator 1.1 installation​

A direct revert from Mediator version 1.1 to 1.0 is not supported. You must remove the 1.1 version and reinstall the 1.0 version.

  1. Delete the Mediator service from the ONTAP configuration: metrocluster configuration-settings mediator remove

  2. Uninstall the 1.1 version of the Mediator service.

    Uninstalling the ONTAP Mediator service

  3. Install the 1.0 version of the Mediator service.

    Installing or upgrading the ONTAP Mediator service

  4. Add the Mediator service to the ONTAP configuration: metrocluster configuration-settings add -address mediator-1.0-ip-address

Recovering from Linux kernel upgrades​

The ONTAP Mediator requires the SCST kernel module. If the Linux kernel is updated, this dependency may lead to a loss of service. It is highly recommended that you rebuild the SCST kernel module when any kernel package changes are made.

Note

  • Upgrading from ONTAP Mediator version 1.0 to 1.1 rebuilds the SCST module.

  • Kernel module changes are applied after the Linux kernel is rebooted.

You can use either of the following procedures to recover from a kernel upgrade that has resulted in loss of service for the Mediator.

ProcedureSteps
Remove and reinstall the SCST kernel module

You must have the SCST tar bundle used by your version of Mediator:

  • ONTAP Mediator 1.0 requires scst-3.3.0.tar.bz2
  • ONTAP Mediator 1.1 requires scst-3.4.0.tar.bz2
  1. Uninstall the SCST module:
    1. Download and untar the SCST tar bundle required by your version of Mediator.
    2. Run the following commands inside of the scst directory:
      systemctl stop mediator-scst
      make scstadm_uninstall
      make iscsi_uninstall
      make usr_uninstall
      make scst_uninstall
      depmod

  2. Reinstall the SCST module for your version of Mediator by issuing the following commands inside of the scst directory:
    make scst_install
    make usr_install
    make iscsi_install
    make scstadm_install
    depmod
    patch /etc/init.d/scst < /opt/lenovo/lib/ontap_mediator/systemd/scst.patch
    reboot
Remove and reinstall ONTAP Mediator
Note
This requires a reconfiguration of the Mediator in ONTAP.

  1. Delete the Mediator service from the ONTAP configuration: metrocluster configuration-settings mediator remove

  2. Uninstall the Mediator service.

    Uninstalling the ONTAP Mediator service

  3. Reinstall the Mediator service.

    Installing or upgrading the ONTAP Mediator service

  4. Add the Mediator service to the ONTAP configuration: metrocluster configuration-settings add -address mediator-ip-address