Attaching a Volume to an Existing OpenStack Instance

When performing a restore from a backup of an OpenStack instance, you can choose to restore a volume and attach it to a different, existing instance.

By attaching a volume to an existing instance, you can access or reuse the data on the volume without restoring the full source instance.

This feature is useful in the following scenarios:

  • An instance has multiple volumes, but you want to restore only some of the volumes.

  • You want to copy and add volumes from one instance to another instance.

  • You want to quickly restore a volume and access the data on the volume.

Note: You can attach a volume to an existing instance and perform cinder volume restore operations only for cinder volumes, not for images. If you select an image for a restore operation that attaches a volume to a different, existing instance or if you perform a cinder volume restore operation on an image, the job might fail.

Before You Begin

If a passkey is configured for restores, you must have the passkey.


  1. From the navigation pane, go to Protect > Virtualization.

    The Virtual machines page appears.

  2. On the Hypervisors tab, click the hypervisor.

    The hypervisor page appears. The VM groups area displays summary information for existing VM groups.

  3. On the VM groups tab, in the row for the VM group, click the action button action_button , and then click Restore.

    The Select restore type page appears.

  4. To restore from a specific copy of backup data, in the upper-right corner of the page, click Settings, and then from the Source list, select the copy.

    If you leave select Automatic selected, the restore operation searches for the requested data in the primary copy, and automatically selects a different copy if the data is not found in the primary copy.

  5. To restore individual volumes and attach volumes to an existing instance, select Attach volume to existing VM.

    The Restore page appears.

  6. Expand the tree on the left and select the objects to be restored on the right. To browse within an item, select the item or click on an entry in the Name column. For hierarchical data such as files, folders, and volumes, you can click an entry in the path listing above the right pane to return to a higher level of the hierarchy.

    In the upper-right corner of the page, a "Showing" message indicates what backup data is displayed. You can click the down arrow beside this message and select any of the following options:

    • Show latest backups: display only data for the most recent backups.

    • Show backups as of a specific date: Display only data up to the date you specify.

    • Show backups for a date range: Display only data within the data range you specify.

  7. Click Restore.

    The Restore Options dialog box appears.

  8. Specify the following information:

    1. Destination hypervisor: To restore to an instance on a different hypervisor, select the hypervisor from the list.

    2. Access node (optional): To use a different proxy, select the proxy from the list.

      By default, the instance volume is restored using the same proxy as the backup.

    3. For each volume you are restoring, specify the following information:

      • Change volume name to (optional): Enter a new display name for the volume.

        If a name was not specified for a volume under the source instance, the volume ID for the source volume is displayed for the volume, and the volume ID is used to name the restored volume unless you enter a different value in the Change volume name to box.

      • Restore to existing instance: Click Browse to select the instance to which you want to attach the restored image.

      • Availability zone: Click Browse to select the zone for the volume.

      • Volume type: Select a volume type that is defined for the zone of the destination volumes.

        If the volume type was not explicitly set during the instance creation, and therefore, set to default, then, during the attach volume restore, you might need to explicitly select a volume type.

  9. Click Submit.