7.4. Updating the Hosts

Use the host upgrade manager to update individual hosts directly from the Red Hat Virtualization Manager.

Note

The upgrade manager only checks hosts with a status of Up or Non-operational, but not Maintenance.

Important

On RHVH, the update only preserves modified content in the /etc and /var directories. Modified data in other paths is overwritten during an update.

Prerequisites

  • If migration is enabled at cluster level, virtual machines are automatically migrated to another host in the cluster; as a result, it is recommended that host updates are performed at a time when the host’s usage is relatively low.
  • Ensure that the cluster contains more than one host before performing an update. Do not attempt to update all the hosts at the same time, as one host must remain available to perform Storage Pool Manager (SPM) tasks.
  • Ensure that the cluster to which the host belongs has sufficient memory reserve in order for its hosts to perform maintenance. If a cluster lacks sufficient memory, the virtual machine migration operation will hang and then fail. You can reduce the memory usage of this operation by shutting down some or all virtual machines before updating the host.
  • You cannot migrate a virtual machine using a vGPU to a different host. Virtual machines with vGPUs installed must be shut down before updating the host.

Procedure

  1. Ensure the correct repositories are enabled. You can check which repositories are currently enabled by running yum repolist.

    • For Red Hat Virtualization Hosts: 

      # subscription-manager repos --enable=rhel-7-server-rhvh-4-rpms

    • For Red Hat Enterprise Linux hosts: 

      # subscription-manager repos --enable=rhel-7-server-rpms
# subscription-manager repos --enable=rhel-7-server-rhv-4-mgmt-agent-rpms
# subscription-manager repos --enable=rhel-7-server-ansible-2-rpms
  2. In the Administration Portal, click Compute → Hosts and select the host to be updated.

  3. Click Installation → Check for Upgrade and click OK.

    Click the Events and alerts notification icon ( EventsIcon ) and expand the Events section to see the result.

  4. If an update is available, click Installation → Upgrade.

  5. Click OK to update the host. Running virtual machines will be migrated according to their migration policy. If migration is disabled for any virtual machines, you will be prompted to shut them down.

    The details of the host are updated in Compute → Hosts and the status transitions through these stages:

    • Maintenance
    • Installing
    • Reboot

    • Up

      If any virtual machines were migrated off the host, they are now migrated back.

      Note

      If the update fails, the host’s status changes to Install Failed. From Install Failed you can click Installation → Upgrade again.

Repeat this procedure for each host in the Red Hat Virtualization environment.