Providing Backups

Percona XtraDB Cluster Operator allows doing cluster backup in two ways. Scheduled backups are configured in the deploy/cr.yaml file to be executed automatically in proper time. On-demand backups can be done manually at any moment.

Backup images are usually stored on Amazon S3 or S3-compatible storage (storing backups on private storage is also possible, but they are described separately).

Making scheduled backups

Since backups are stored separately on the Amazon S3, a secret with AWS_ACCESS_KEY_ID and AWS_SECRET_ACCESS_KEY should be present on the Kubernetes cluster. The secrets file with these keys should be created: for example deploy/backup-s3.yaml file with the following contents:

   apiVersion: v1
   kind: Secret
   metadata:
     name: my-cluster-name-backup-s3
   type: Opaque
   data:
     AWS_ACCESS_KEY_ID: UkVQTEFDRS1XSVRILUFXUy1BQ0NFU1MtS0VZ
     AWS_SECRET_ACCESS_KEY: UkVQTEFDRS1XSVRILUFXUy1TRUNSRVQtS0VZ

The name value is the Kubernetes secret name which will be used further, and AWS_ACCESS_KEY_ID and AWS_SECRET_ACCESS_KEY are the keys to access S3 storage (and obviously they should contain proper values to make this access possible). To have effect secrets file should be applied with the appropriate command to create the secret object, e.g. kubectl apply -f deploy/backup-s3.yaml (for Kubernetes).

Backups schedule is defined in the backup section of the deploy/cr.yaml file. This section contains following subsections:

  • storages subsection contains data needed to access the S3-compatible cloud to store backups.
  • schedule subsection allows to actually schedule backups (the schedule is specified in crontab format).

Here is an example which uses Amazon S3 storage for backups:

   ...
   backup:
     enabled: true
     version: 0.3.0
     ...
     storages:
       s3-us-west:
         type: s3
         s3:
           bucket: S3-BACKUP-BUCKET-NAME-HERE
           region: us-west-2
           credentialsSecret: my-cluster-name-backup-s3
     ...
     schedule:
      - name: "sat-night-backup"
        schedule: "0 0 * * 6"
        keep: 3
        storageName: s3-us-west
     ...

Note: if you use some S3-compatible storage instead of the original Amazon S3, one more key is needed in the s3 subsection: the endpointUrl, which points to the actual cloud used for backups and is specific to the cloud provider. For example, using Google Cloud involves the following one: endpointUrl: https://storage.googleapis.com.

The options within these three subsections are further explained in the Operator Options.

The only option which should be mentioned separately is credentialsSecret which is a Kubernetes secret for backups. Value of this key should be the same as the name used to create the secret object (my-cluster-name-backup-s3 in the last example).

The schedule is specified in crontab format as explained in the Operator Options.

Making on-demand backup

To make on-demand backup, user should use YAML file with correct names for the backup and the PXC Cluster, and correct PVC settings. The example of such file is deploy/backup/cr.yaml.

When the backup config file is ready, actual backup command is executed:

   kubectl apply -f deploy/backup/cr.yaml

Note: Storing backup settings in a separate file can be replaced by passing its content to the kubectl apply command as follows:

   cat <<EOF | kubectl apply -f-
   apiVersion: "pxc.percona.com/v1alpha1"
   kind: "PerconaXtraDBBackup"
   metadata:
     name: "backup1"
   spec:
     pxcCluster: "cluster1"
     storageName: "s3-us-west"
   EOF

Restore the cluster from a previously saved backup

Following steps are needed to restore a previously saved backup:

  1. First of all make sure that the cluster is running.
  2. Now find out correct names for the backup and the cluster. Available backups can be listed with the following command:
    kubectl get pxc-backup
    

    And the following command will list available clusters:

    kubectl get pxc
    
  3. When both correct names are known, the actual restoration process can be started as follows:
    ./deploy/backup/restore-backup.sh <backup-name> <cluster-name>
    

Delete the unneeded backup

Deleting a previously saved backup requires not more than the backup name. This name can be taken from the list of available backups returned by the following command:

   kubectl get pxc-backup

When the name is known, backup can be deleted as follows:

   kubectl delete pxc-backup/<backup-name>

Copy backup to a local machine

Make a local copy of a previously saved backup requires not more than the backup name. This name can be taken from the list of available backups returned by the following command:

   kubectl get pxc-backup

When the name is known, backup can be downloaded to the local machine as follows:

   ./deploy/backup/copy-backup.sh <backup-name> path/to/dir

For example, this downloaded backup can be restored to the local installation of Percona Server:

   service mysqld stop
   rm -rf /var/lib/mysql/*
   cat xtrabackup.stream | xbstream -x -C /var/lib/mysql
   xtrabackup --prepare --target-dir=/var/lib/mysql
   chown -R mysql:mysql /var/lib/mysql
   service mysqld start