Upgrading KVM Hosts from Oracle Linux 8 to Oracle Linux 9

During the upgrade process, you must migrate all virtual machines to another host in the environment. Doing so minimizes the downtime of virtual machines in the environment. After the upgrade, you can reattach the KVM host to the engine and migrate the virtual machines back to the host.

Caution:

  • When installing or reinstalling the host's OS, we strongly recommend that you first detach any existing non-OS storage from the host to avoid potential data loss from accidental initialization of these disks.
  • Upgrading from 4.4 to 4.5 with Gluster 8 storage in the environment is supported for Oracle 8 KVM hosts, but isn't supported for Oracle 9 KVM hosts. You must remove Gluster before upgrading.

  1. Verify the 4.5 engine is installed and running.

  2. (Optional) Verify that all data centers and clusters in the environment are at the same compatibility level.

  3. Pick a host to upgrade and migrate the host's virtual machines to another host in the same cluster.

    You can use Live Migration to minimize virtual machine downtime. See Migrating Virtual Machines between Hosts.

  4. Put the host into maintenance mode.

    See Moving a Host to Maintenance Mode.

  5. Remove the host from the engine.

    See Removing a Host.

  6. Install Oracle Linux 9.6 or later release. Even if you're using the same physical machine as with Oracle Linux 8 KVM, the Oracle Linux 9 KVM hosts require a clean installation of Oracle Linux 9.6 or later Oracle Linux 9 release.

    Caution:

    Before you install, review the prerequisites. Then, follow the instructions in Configure a KVM Host in the Oracle Linux Virtualization Manager Getting Started guide.

    Ensure that you select Minimal Install as the base environment for the installation. If you don't, the hosts will have incorrect qemu and libvirt versions, incorrect repositories configured, and no access to virtual machine consoles.

  7. Add the host to the engine.