General

When backing up resources in OpenStack, it's important to understand the difference between two primary methods:

1. Volume Backups (Cinder): These are point-in-time copies of block storage volumes. Volume backups preserve the data within a volume and can be used to restore the volume to the exact state it was in when backed up. They're ideal for data recovery and are managed through the Cinder service.
2. VM Images (Glance): These capture the entire virtual machine, including the operating system, applications, and configuration. VM images are useful for cloning VMs, creating templates, or disaster recovery scenarios. They're managed through the Glance service.

Choose the appropriate method based on your recovery needs: volume backups for data recovery, VM images for full system recovery or replication.

Volume Backups

List available backups

To list all available backups in your cloud, you can use the following command:

openstack volume backup list

Additionally, you can filter the results with additional options to list backups for a specific volume:

 openstack volume backup list --volume VOLUME_ID

Creating Backups

To create a backup of a volume:

openstack volume backup create [--incremental] [--force] [--name NAME] VOLUME

Where:

• --incremental: Create an incremental backup (requires a previous full backup)
• --force: Create a backup even if the volume is attached
• --name NAME: Specify a name for the backup
• VOLUME: The ID or name of the volume to back up

Restoring Backups

1. To restore a backup to a new volume, first you need to detach the volume from the VM:
   1. ssh into your VM
   2. become root
   3. unmount the volume 

      sudo umount --verbose <path-to-volume>

2. Then you can restore the backup to the volume with OpenStack (from the machine where you are running Openstack commands):

openstack volume backup restore BACKUP_ID VOLUME_ID

Where:

• BACKUP_ID: The ID of the backup to restore
• VOLUME_ID: The ID of the volume to restore to (must be at least as large as the original volume)

3. Now, you need to attach the volume again to the VM as explained in `Configuring the extra volume in the instance`.

VM Images Backup

List available image

To list all available images:

openstack image list

Creating VM Images Snapshots

To create a new VM image snapshot:

openstack server image create --name IMAGE_NAME SERVER

Where:

• --name IMAGE_NAME: The name for the new image snapshot
• SERVER: The above command creates the image SERVERby taking a snapshot of a running server.

Restoring VMs from Images

OpenStack  provide a mechanism to replace the underlying disk of an existing VM with an image without creating a new VM instance running the following command:

openstack server rebuild VM-NAME --image IMAGE_ID

where

• VM-NAME: The name of the existing image

• IMAGE_ID: Name of the backup image of the VM you created before