Providing Backups¶

The Operator usually stores Percona XtraDB Cluster backups outside the Kubernetes cluster, on Amazon S3 or S3-compatible storage, or on Azure Blob Storage:

But storing backups on Persistent Volumes inside the Kubernetes cluster is also possible:

The Operator allows doing backups 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 and are configured in the deploy/backup/backup.yaml.

Making scheduled backups¶

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

storages subsection contains data and configuration needed to store backups,
schedule subsection allows to actually schedule backups (the schedule is specified in crontab format).

Backups on Amazon S3 or S3-compatible storage¶

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 base64-encoded keys should be created: for example deploy/backup/backup-secret-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

Note

The following command can be used to get a base64-encoded string from a plain text one:

in Linuxin macOS

$ echo -n 'plain-text-string' | base64 --wrap=0

$ echo -n 'plain-text-string' | base64

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/backup-secret-s3.yaml (for Kubernetes).

Note

In case if the previous backup attempt fails (because of a temporary networking problem, etc.) the backup job tries to delete the unsuccessful backup leftovers first, and then makes a retry. Therefore there will be no backup retry without DELETE permissions to the objects in the bucket. Also, setting Google Cloud Storage Retention Period can cause a similar problem.

All the data needed to access the S3-compatible cloud to store backups (credentials, name of the bucket to keep backups in, etc.)should be put into the backup.storages subsection, and backup.schedule subsection should actually schedule backups in crontab-compatible way. Here is an example of deploy/cr.yaml which uses Amazon S3 storage for backups:

...
backup:
  ...
  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
  ...

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

endpointUrl: https://storage.googleapis.com

The options within these three subsections are further explained in the Custom Resource options.

One 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).

Backups on Microsoft Azure Blob storage¶

Since backups are stored separately on Azure Blob Storage, a secret with AZURE_STORAGE_ACCOUNT_NAME and AZURE_STORAGE_ACCOUNT_KEY should be present on the Kubernetes cluster. The secrets file with these base64-encoded keys should be created: for example deploy/backup/backup-secret-azure.yaml file with the following contents.

apiVersion: v1
kind: Secret
metadata:
  name: my-cluster-azure-secret
type: Opaque
data:
  AZURE_STORAGE_ACCOUNT_NAME: UkVQTEFDRS1XSVRILUFaVVJFLVNUT1JBR0UtQUNDT1VOVC1OQU1F
  AZURE_STORAGE_ACCOUNT_KEY: UkVQTEFDRS1XSVRILUFaVVJFLVNUT1JBR0UtQUNDT1VOVC1LRVk=

Note

The following command can be used to get a base64-encoded string from a plain text one:

in Linuxin macOS

$ echo -n 'plain-text-string' | base64 --wrap=0

$ echo -n 'plain-text-string' | base64

The name value is the Kubernetes secret name which will be used further. The AZURE_STORAGE_ACCOUNT_NAME and AZURE_STORAGE_ACCOUNT_KEY credentials will be used to access the 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 Secrets object, e.g. kubectl apply -f deploy/backup/backup-secret-azure.yaml (for Kubernetes).

All the data needed to access the Azure Blob storage to store backups (credentials, name of the container to keep backups in, etc.) should be put into the backup.storages subsection, and backup.schedule subsection should actually schedule backups in crontab-compatible way. Here is an example of deploy/cr.yaml which uses Azure Blob storage for backups:

...
backup:
  enabled: true
  ...
  storages:
    azure-blob:
      type: azure
      azure:
        credentialsSecret: my-cluster-azure-secret
        container: <your-container-name>
  ...
  schedule:
    - name: "sat-night-backup"
        schedule: "0 0 * * 6"
        keep: 3
        storageName: azure-blob
  ...

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

One 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-azure-secret in the last example).

Making on-demand backup¶

To make an on-demand backup, the user should first configure the backup storage in the backup.storages subsection of the deploy/cr.yaml configuration file in a same way it was done for scheduled backups. When the deploy/cr.yaml file contains correctly configured storage and is applied with kubectl command, use a special backup configuration YAML file with the following contents:

backup name in the metadata.name key,
Percona XtraDB Cluster name in the spec.pxcCluster key,
storage name from deploy/cr.yaml in the spec.storageName key,
S3 backup finalizer set by the metadata.finalizers.delete-s3-backup key (it triggers the actual deletion of backup files from the S3 bucket when there is a manual or scheduled removal of the corresponding backup object).

The example of the backup configuration file is deploy/backup/backup.yaml.

When the backup destination is configured and applied with kubectl apply -f deploy/cr.yaml command, the actual backup command is executed:

$ kubectl apply -f deploy/backup/backup.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: PerconaXtraDBClusterBackup
metadata:
  finalizers:
    - delete-s3-backup
  name: backup1
spec:
  pxcCluster: cluster1
  storageName: s3-us-west
EOF

Storing binary logs for point-in-time recovery¶

Point-in-time recovery functionality allows users to roll back the cluster to a specific transaction, time (or even skip a transaction in some cases). Technically, this feature involves continuously saving binary log updates to the backup storage. Point-in-time recovery is off by default and is supported by the Operator only with Percona XtraDB Cluster versions starting from 8.0.21-12.1.

To be used, it requires setting a number of keys in the pitr subsection under the backup section of the deploy/cr.yaml file:

enabled key should be set to true,
storageName key should point to the name of the storage already configured in the storages subsection

Note

Both binlog and full backup should use s3-compatible storage to make point-in-time recovery work!
timeBetweenUploads key specifies the number of seconds between running the binlog uploader.

Following example shows how the pitr subsection looks like:

backup:
  ...
  pitr:
    enabled: true
    storageName: s3-us-west
    timeBetweenUploads: 60

Note

Point-in-time recovery will be done for binlogs without any cluster-based filtering. Therefore it is recommended to use a separate storage, bucket, or directory to store binlogs for the cluster. Also, it is recommended to have empty bucket/directory which holds binlogs (with no binlogs or files from previous attempts or other clusters) when you enable point-in-time recovery.

Note

Purging binlogs before they are transferred to backup storage will break point-in-time recovery.

Storing backup on Persistent Volume¶

Here is an example of the deploy/cr.yaml backup section fragment, which configures a private volume for filesystem-type storage:

...
backup:
  ...
  storages:
    fs-pvc:
      type: filesystem
      volume:
        persistentVolumeClaim:
          accessModes: [ "ReadWriteOnce" ]
          resources:
            requests:
              storage: 6Gi
  ...

Note

Please take into account that 6Gi storage size specified in this example may be insufficient for the real-life setups; consider using tens or hundreds of gigabytes. Also, you can edit this option later, and changes will take effect after applying the updated deploy/cr.yaml file with kubectl.

Enabling compression for backups¶

There is a possibility to enable LZ4 compression for backups.

Note

This feature is available only with Percona XtraDB Cluster 8.0 and not Percona XtraDB Cluster 5.7.

To enable compression, use pxc.configuration key in the deploy/cr.yaml configuration file to supply Percona XtraDB Cluster nodes with two additional my.cnf options under its [sst] and [xtrabackup] sections as follows:

pxc:
  image: percona/percona-xtradb-cluster:8.0.19-10.1
  configuration: |
    ...
    [sst]
    xbstream-opts=--decompress
    [xtrabackup]
    compress=lz4
    ...

When enabled, compression will be used for both backups and SST.

Restore the cluster from a previously saved backup¶

Backups can be restored not only on the Kubernetes cluster where it was made, but also on any Kubernetes-based environment with the installed Operator.

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.

Note

When restoring to a new Kubernetes-based environment, make sure it has a Secrets object with the same user passwords as in the original cluster. More details about secrets can be found in System Users.

The example of the restore configuration file is deploy/backup/restore.yaml. The options that can be used in it are described 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
```

Note

Obviously, you can make this check only on the same cluster on which you have previously made the backup.

And the following command will list existing Percona XtraDB Cluster names in the current Kubernetes-based environment:

$ kubectl get pxc

Restoring backup¶

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

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,
- if you are restoring backup on the same Kubernetes-based cluster you have used to save this backup, set spec.backupName key to the name of your backup,
- if you are restoring backup on the Kubernetes-based cluster different from one you have used to save this backup, set spec.backupSource subsection instead of spec.backupName field to point on the appropriate PVC, or cloud storage:
  PVC volumeS3-compatible storageAzure Blob storage
  The backupSource key should contain the storage name (which should be configured in the main CR) and PVC Name:
  
  ... backupSource: destination: pvc/PVC_VOLUME_NAME storageName: pvc ...
  
  Note
  
  If you need a headless Service for the restore Pod (i.e. restoring from a Persistent Volume in a tenant network), mention this in the metadata.annotations as follows:
  
  annotations: percona.com/headless-service: "true" ...
  The backupSource key should contain destination key equal to the S3 bucket with a special s3:// prefix, followed by the necessary S3 configuration keys, same as in deploy/cr.yaml file:
  
  ... backupSource: destination: s3://S3-BUCKET-NAME/BACKUP-NAME s3: bucket: S3-BUCKET-NAME credentialsSecret: my-cluster-name-backup-s3 region: us-west-2 endpointUrl: https://URL-OF-THE-S3-COMPATIBLE-STORAGE ...
  The backupSource key should contain destination key equal to the Azure Blob container and backup name, followed by the necessary Azure configuration keys, same as in deploy/cr.yaml file:
  
  ... backupSource: destination: AZURE-CONTAINER-NAME/BACKUP-NAME azure: container: AZURE-CONTAINER-NAME credentialsSecret: my-cluster-azure-secret ...

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

Restoring backup 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.

If the point-in-time recovery feature was enabled, you can put additional restoration parameters to the restore.yaml file pitr section for the most fine-grained restoration.

backupSource key should contain destination key equal to the s3 bucket with a special s3:// prefix, followed by the necessary S3 configuration keys, same as in deploy/cr.yaml file: s3://S3-BUCKET-NAME/BACKUP-NAME,
type key can be equal to one of the following options,
- date - roll back to specific date,
- transaction - roll back to 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,
if you have necessary backup storage mentioned in the backup.storages subsection of the deploy/cr.yaml configuration file, you can just set backupSource.storageName key in the deploy/backup/restore.yaml file to the name of the appropriate storage,

if there is no necessary backup storage in deploy/cr.yaml, set your storage details instead of using the backupSource.storageName field:

 ...
 backupSource:
   s3:
     bucket: S3-BUCKET-NAME
     credentialsSecret: my-cluster-name-backup-s3
     endpointUrl: https://URL-OF-THE-S3-COMPATIBLE-STORAGE
     region: us-west-2
...

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"

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"
  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"

Delete the unneeded backup¶

The maximum amount of stored backups is controlled by the backup.schedule.keep option (only successful backups are counted). Older backups are automatically deleted, so that amount of stored backups do not exceed this number. Setting keep=0 or removing this option from deploy/cr.yaml disables automatic deletion of backups.

Manual deleting 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 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

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Last update: 2023-02-09