10.7. Updating All Hosts in a Cluster

You can update all hosts in a cluster instead of updating hosts individually. This is particularly useful during upgrades to new versions of Red Hat Virtualization. See https://github.com/oVirt/ovirt-ansible-cluster-upgrade/blob/master/README.md for more information about the Ansible role used to automate the updates.

Red Hat recommends updating one cluster at a time.

Limitations

  • On RHVH, the update only preserves modified content in the /etc and /var directories. Modified data in other paths is overwritten during an update.
  • If migration is enabled at the cluster level, virtual machines are automatically migrated to another host in the cluster.
  • In a self-hosted engine environment, the Manager virtual machine can only migrate between self-hosted engine nodes in the same cluster. It cannot migrate to standard hosts.
  • The cluster must have sufficient memory reserved for its hosts to perform maintenance. Otherwise, virtual machine migrations will hang and fail. You can reduce the memory usage of host updates by shutting down some or all virtual machines before updating hosts.
  • You cannot migrate a pinned virtual machine (such as a virtual machine using a vGPU) to another host. Pinned virtual machines are shut down during the update, unless you choose to skip that host instead.

Procedure

  1. In the Administration Portal, click ComputeClusters and select the cluster.
  2. Click Upgrade.
  3. Select the hosts to update, then click Next.
  4. Configure the options:

    • Stop Pinned VMs shuts down any virtual machines that are pinned to hosts in the cluster, and is selected by default. You can clear this check box to skip updating those hosts so that the pinned virtual machines stay running, such as when a pinned virtual machine is running important services or processes and you do not want it to shut down at an unknown time during the update.
    • Upgrade Timeout (Minutes) sets the time to wait for an individual host to be updated before the cluster upgrade fails with a timeout. The default is 60. You can increase it for large clusters where 60 minutes might not be enough, or reduce it for small clusters where the hosts update quickly.
    • Check Upgrade checks each host for available updates before running the upgrade process. It is not selected by default, but you can select it if you need to ensure that recent updates are included, such as when you have configured the Manager to check for host updates less frequently than the default.
    • Reboot After Upgrade reboots each host after it is updated, and is selected by default. You can clear this check box to speed up the process if you are sure that there are no pending updates that require a host reboot.
    • Use Maintenance Policy sets the cluster’s scheduling policy to cluster_maintenance during the update. It is selected by default, so activity is limited and virtual machines cannot start unless they are highly available. You can clear this check box if you have a custom scheduling policy that you want to keep using during the update, but this could have unknown consequences. Ensure your custom policy is compatible with cluster upgrade activity before disabling this option.
  5. Click Next.
  6. Review the summary of the hosts and virtual machines that will be affected.
  7. Click Upgrade.

You can track the progress of host updates in the ComputeHosts view, and in the Events section of the Notification Drawer ( EventsIcon ).

You can track the progress of individual virtual machine migrations in the Status column of the ComputeVirtual Machines view. In large environments, you may need to filter the results to show a particular group of virtual machines.