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Storage

[!NOTE]
This documentation applies to mariadb-operator version >= v0.0.26

This operator gives you flexibility to define the storage that will back the /var/lib/mysql data directoty mounted by MariaDB.

Table of contents

Configuration

The simplest way to configure storage for your MariaDB is:

apiVersion: k8s.mariadb.com/v1alpha1
kind: MariaDB
metadata:
  name: mariadb-galera
spec:
  ...
  storage:
    size: 1Gi

This will make use of the default StorageClass available in your cluster, but you can also provide a different one:

apiVersion: k8s.mariadb.com/v1alpha1
kind: MariaDB
metadata:
  name: mariadb-galera
spec:
  ...
  storage:
    size: 1Gi
    storageClassName: my-storage-class

Under the scenes, the operator is configuring the StatefulSet's volumeClaimTemplate property, which you are also able to provide yourself:

apiVersion: k8s.mariadb.com/v1alpha1
kind: MariaDB
metadata:
  name: mariadb-galera
spec:
  ...
  storage:
    size: 1Gi
    storageClassName: standard
    volumeClaimTemplate:
      accessModes:
      - ReadWriteOnce
      resources:
        requests:
          storage: 1Gi
      storageClassName: standard

Volume resize

[!WARNING]
The StorageClass used for volume resizing must define allowVolumeExpansion = true.

It is possible to resize your storage after having provisioned a MariaDB. We need to distinguish between: - PVCs already in use. - StatefulSet storage size, which will be used when provisioning new replicas.

It is important to note that, for the first case, your StorageClass must support volume expansion by declaring the allowVolumeExpansion = true. In such case, it will be safe to expand the storage by increasing the size and setting resizeInUseVolumes = true:

apiVersion: k8s.mariadb.com/v1alpha1
kind: MariaDB
metadata:
  name: mariadb-galera
spec:
  ...
  storage:
    size: 2Gi
    resizeInUseVolumes: true
    waitForVolumeResize: true

Depending on your storage provider, this operation might take a while, and you can decide to wait for this operation before the MariaDB becomes ready by setting waitForVolumeResize = true. Operations such as cluster recovery and primary switchover will not be performed if the MariaDB resource is not ready.

Ephemeral storage

Provisioning standalone MariaDB instances is also possible by setting ephemeral = true:

apiVersion: k8s.mariadb.com/v1alpha1
kind: MariaDB
metadata:
  name: mariadb-galera
spec:
  ...
  storage:
    ephemeral: true

This may be useful more multiple use cases, like provisioning ephemeral MariaDBs for the integration tests of your CI.

Reference