Pre-requisite: EWC - OpenStack Command-Line client
Foreword
Before backing up resources in OpenStack, it's important to understand the difference between three primary methods:
- Intance Snapshots (Glance): These capture the entire virtual machine, including the operating system, applications, and configuration. Instance snapshots are useful for cloning VMs, creating templates, or disaster recovery scenarios. They're managed through the Glance service.
- Volume Snapshots (Cinder): These are delta copies of the block storage volumes. Volume snapshots are not full copies and rely on the original volume for restoration, so they are mostly useful for accident recovery. They're managed through the Cinder service.
- 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.
Choose the appropriate method based on your recovery needs: instance snapshots for full system recovery or replication, volume snapshots for accident prevention and recovery or volume backups for full data security and recovery.
Before starting make sure you are in the machine where you configured openstack client and you can run openstack commands as described in EWC - OpenStack Command-Line client
When creating backups or snapshots of VMs and volumes, it is highly recommended that the following command are run outside from said VMs and volumes. Doing so from within may cause corrupted backups or snapshots.
Backup VMs and volumes
Instance Snapshots
To take a snapshot of a instance for later recovery or replication, one must create an image based on the current VM. The list of VMs/servers than can be used for the snapshot can be found with:
openstack server list
And, to create the image snapshot of a running VM with name or id <server> use the command
openstack server image create --name <image_name> <server>
where:
--name <image_name>: the name for the new image snapshot<server>: the name or id of your server / VM to be backed up.
In order to see the list of images, including the recently created snapshot, one can run
openstack image list
and the specific details of the created image can be found
openstack image show <image_name>
Volume Snapshots
To create a snapshot of a volume
openstack volume snapshot [--force] --volume <volume> <snapshot_name>
with:
--force: create the snapshot even if the volume is attached–volume <volume>: the name or id of the volume to be backed up<snapshot_name>: the name of the new volume snapshot
To see the list of all snapshots in your cloud, or the snapshots from a specific volume, run
openstack volume snapshot list [--volume <volume>]
and to get the details of a specific snapshot
openstack volume snapshot show <snapshot_name>
Volume Backups
To create a backup of a volume run:
openstack volume backup create [--incremental] [--force] [--name <backup_name>] <volume>
Where:
--incremental:create an incremental backup (requires a previous full backup)--force:create a backup even if the volume is attached--name <backup_name>: the name of the new volume backup<volume>: the name or id of the volume to be backed up
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
It is usually recommended to unmount the volumes before backing them up, to avoid potential crashes. Nevertheless, one can force the backup of attached volumes with the --force option. The snapshot or backup of an attached volume is crash consistent.
Common use cases
These is a list of common configurations of VMs and volumes in the cloud and the recommened procedure to backing them up
Single VM
WIP
Single VM and attached volume(s)
WIP
Single VM and multiple networks
WIP
Single VM and SFS
WIP
Multiple VMs
WIP
Automatic backups
WIP