15.4. Updating the machine type to Q35

Procedure

1. Identify the instances that have no machine type recorded in the database:

   $nova-manage libvirt list_unset_machine_type

   1. If you find instances that have no machine type, use the following command to record a machine type for each instance:

      $nova-manage libvirt update_machine_type <instance_uuid> <machine_type>

      • Replace <instance_uuid> with the UUID of the instance.
      • Replace <machine_type> with the machine type originally used when the instance was created.

2. For each instance, show the machine type of the instance so you know what needs to be updated:

   $nova-manage libvirt get_machine_type <instance_uuid>

3. For each instance that needs to have its machine type changed to q35, complete the following steps:

   1. Test that the OS within the instance is compatible with the new hardware:

      1. Create a test instance.

      2. Verify that the test instance has a machine type other than q35:

         $nova-manage libvirt get_machine_type <test_instance_uuid>

      3. Stop the test instance:

         $openstack server stop <test_instance_uuid>

      4. Update the machine type of the test instance to q35:

         $nova-manage libvirt update_machine_type <test_instance_uuid> q35 --force

      5. Start the test instance:

         $openstack server start <test_instance_uuid>

      6. Verify that you can log in to the test instance and ensure that it is working as expected.

   2. In a test environment, verify that the OS within the instance can tolerate the change without re-creation:

      1. Stop the instance:

         $openstack server stop <instance_uuid>

      2. Update the machine type and use the --force value:

         $nova-manage libvirt update_machine_type <instance_uuid> q35 --force

      3. Update the disk controller bus and set hw_cdrom_bus to sata:

         $nova-manage image_property set <instance_uuid> --property hw_cdrom_bus=sata

      4. Start the instance:

         $openstack server start <instance_uuid>