Restore the cluster from a previously saved backup¶

The backup is normally restored on the Kubernetes cluster where it was made, but restoring it on a different Kubernetes-based environment with the installed Operator is also possible.

Backups cannot be restored to emptyDir and hostPath volumes, but it is possible to make a backup from such storage (i. e., from emptyDir/hostPath to S3), and later restore it to a Persistent Volume .

To restore a backup, you will use the special restore configuration file. The example of such file is deploy/backup/restore.yaml . The list of options that can be used in it can be found in the restore options reference.

Following things are needed to restore a previously saved backup:

Make sure that the cluster is running.
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
```

Note

If you have configured storing binlogs for point-in-time recovery, you will have possibility to roll back the cluster to a specific transaction, time (or even skip a transaction in some cases). Otherwise, restoring backups without point-in-time recovery is the only option.

When the correct names for the backup and the cluster are known, backup restoration can be done in the following way.

Restore the cluster without point-in-time recovery¶

Set appropriate keys in the deploy/backup/restore.yaml file.
- set spec.pxcCluster key to the name of the target cluster to restore the backup on,
- set spec.backupName key to the name of your backup,
- you can also use a storageName key to specify the exact name of the storage (the actual storage should be already defined in the backup.storages subsection of the deploy/cr.yaml file):
```
apiVersion: pxc.percona.com/v1
kind: PerconaXtraDBClusterRestore
metadata:
  name: restore1
spec:
  pxcCluster: cluster1
  backupName: backup1
  storageName: s3-us-west
```

After that, the actual restoration process can be started as follows:

$ kubectl apply -f deploy/backup/restore.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/v1"
kind: "PerconaXtraDBClusterRestore"
metadata:
  name: "restore1"
spec:
  pxcCluster: "cluster1"
  backupName: "backup1"
EOF

Restore the cluster with point-in-time recovery¶

Note

Disable the point-in-time functionality on the existing cluster before restoring a backup on it, regardless of whether the backup was made with point-in-time recovery or without it.

Set appropriate keys in the deploy/backup/restore.yaml file.
- set spec.pxcCluster key to the name of the target cluster to restore the backup on,
- set spec.backupName key to the name of your backup,
- put additional restoration parameters to the pitr section:
  - type key can be equal to one of the following options,
    - date - roll back to specific date,
    - transaction - roll back to a specific transaction (available since Operator 1.8.0),
    - latest - recover to the latest possible transaction,
    - skip - skip a specific transaction (available since Operator 1.7.0).
  - date key is used with type=date option and contains value in datetime format,
  - gtid key (available since the Operator 1.8.0) is used with type=transaction option and contains exact GTID of a transaction which follows the last transaction included into the recovery
- use backupSource.storageName key to specify the exact name of the storage (the actual storage should be already defined in the backup.storages subsection of the deploy/cr.yaml file).
The resulting restore.yaml file may look as follows:
```
apiVersion: pxc.percona.com/v1
kind: PerconaXtraDBClusterRestore
metadata:
  name: restore1
spec:
  pxcCluster: cluster1
  backupName: backup1
  pitr:
    type: date
    date: "2020-12-31 09:37:13"
    backupSource:
      storageName: "s3-us-west"
```
Note

Full backup objects available with the kubectl get pxc-backup command have a “Latest restorable time” information field handy when selecting a backup to restore. You can easily query the backup for this information as follows:
```
$ kubectl get pxc-backup <backup_name> -o jsonpath='{.status.latestRestorableTime}'
```

Run the actual restoration process:

$ kubectl apply -f deploy/backup/restore.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/v1"
kind: "PerconaXtraDBClusterRestore"
metadata:
  name: "restore1"
spec:
  pxcCluster: "cluster1"
  backupName: "backup1"
  pitr:
    type: date
    date: "2020-12-31 09:37:13"
    backupSource:
      storageName: "s3-us-west"
EOF

Take into account, that Operator monitors the binlog gaps detected by binlog collector, if any. If backup contains such gaps, the Operator will mark the status of the latest successful backup with a new condition field that indicates backup can’t guarantee consistent point-in-time recovery. This condition looks as follows:

apiVersion: pxc.percona.com/v1
kind: PerconaXtraDBClusterBackup
metadata:
  name: backup1
spec:
  pxcCluster: pitr
  storageName: minio
status:
  completed: "2022-11-25T15:57:29Z"
  conditions:
  - lastTransitionTime: "2022-11-25T15:57:48Z"
    message: Binlog with GTID set e41eb219-6cd8-11ed-94c8-9ebf697d3d20:21-22 not found
    reason: BinlogGapDetected
    status: "False"
    type: PITRReady
  state: Succeeded

Trying to restore from such backup (with the condition value “False”) with point-in-time recovery will result in the following error:

Backup doesn't guarantee consistent recovery with PITR. Annotate PerconaXtraDBClusterRestore with percona.com/unsafe-pitr to force it.

You can disable this check and force the restore by annotating it with pxc.percona.com/unsafe-pitr as follows:

apiVersion: pxc.percona.com/v1
kind: PerconaXtraDBClusterRestore
metadata:
  annotations:
    percona.com/unsafe-pitr: "true"
  name: restore2
spec:
  pxcCluster: pitr
  backupName: backup1
  pitr:
    type: latest
    backupSource:
      storageName: "minio-binlogs"

Restore the cluster when backup has different passwords¶

If the cluster is restored to a backup which has different user passwords, the Operator will be unable connect to database using the passwords in Secrets, and so will fail to reconcile the cluster.

Let’s consider an example with four backups, first two of which were done before the password rotation and therefore have different passwords:

NAME      CLUSTER    STORAGE   DESTINATION      STATUS      COMPLETED   AGE
backup1   cluster1   fs-pvc    pvc/xb-backup1   Succeeded   23m         24m
backup2   cluster1   fs-pvc    pvc/xb-backup2   Succeeded   18m         19m
backup3   cluster1   fs-pvc    pvc/xb-backup3   Succeeded   13m         14m
backup3   cluster1   fs-pvc    pvc/xb-backup4   Succeeded   8m53s       9m29s
backup4   cluster1   fs-pvc    pvc/xb-backup5   Succeeded   3m11s       4m29s

In this case you will need some manual operations same as the Operator does to propagate password changes in Secrets to the database before restoring a backup.

When the user updates a password in the Secret, the Operator creates a temporary Secret called <clusterName>-mysql-init and puts (or appends) the required ALTER USER statement into it. Then MySQL Pods are mounting this init Secret if exist and running corresponding statements on startup. When a new backup is created and successfully finished, the Operator deletes the init Secret.

In the above example passwords are changed after backup2 was finished, and then three new backups were created, so the init Secret does not exist. If you want to restore to backup2, you need to create the init secret by your own with the latest passwords as follows.

Make a base64-encoded string with needed SQL statements (substitute each <latestPass> with the password of the appropriate user):

in Linuxin macOS

$ cat <<EOF | base64 --wrap=0
ALTER USER 'root'@'%' IDENTIFIED BY '<latestPass>';
ALTER USER 'root'@'localhost' IDENTIFIED BY '<latestPass>';
ALTER USER 'operator'@'%' IDENTIFIED BY '<latestPass>';
ALTER USER 'monitor'@'%' IDENTIFIED BY '<latestPass>';
ALTER USER 'clustercheck'@'localhost' IDENTIFIED BY '<latestPass>';
ALTER USER 'xtrabackup'@'%' IDENTIFIED BY '<latestPass>';
ALTER USER 'xtrabackup'@'localhost' IDENTIFIED BY '<latestPass>';
ALTER USER 'replication'@'%' IDENTIFIED BY '<latestPass>';
EOF

$ cat <<EOF | base64
ALTER USER 'root'@'%' IDENTIFIED BY '<latestPass>';
ALTER USER 'root'@'localhost' IDENTIFIED BY '<latestPass>';
ALTER USER 'operator'@'%' IDENTIFIED BY '<latestPass>';
ALTER USER 'monitor'@'%' IDENTIFIED BY '<latestPass>';
ALTER USER 'clustercheck'@'localhost' IDENTIFIED BY '<latestPass>';
ALTER USER 'xtrabackup'@'%' IDENTIFIED BY '<latestPass>';
ALTER USER 'xtrabackup'@'localhost' IDENTIFIED BY '<latestPass>';
ALTER USER 'replication'@'%' IDENTIFIED BY '<latestPass>';
EOF

After you obtained the needed base64-encoded string, create the appropriate Secret:

$ kubectl apply -f - <<EOF
apiVersion: v1
kind: Secret
type: Opaque
metadata:
  name: cluster1-mysql-init
data:
  init.sql: <base64encodedstring>
EOF

Now you can restore the needed backup as usual.

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Last update: 2024-10-29