You are looking at the documentation of a prior release. To read the documentation of the latest release, please visit here.

New to KubeDB? Please start here.

MariaDB Volume Expansion

This guide will show you how to use KubeDB Enterprise operator to expand the volume of a MariaDB.

Before You Begin

At first, you need to have a Kubernetes cluster, and the kubectl command-line tool must be configured to communicate with your cluster.
You must have a StorageClass that supports volume expansion.
Install KubeDB Community and Enterprise operator in your cluster following the steps here.
You should be familiar with the following KubeDB concepts:

To keep everything isolated, we are going to use a separate namespace called demo throughout this tutorial.

$ kubectl create ns demo
namespace/demo created

Expand Volume of MariaDB

Here, we are going to deploy a MariaDB cluster using a supported version by KubeDB operator. Then we are going to apply MariaDBOpsRequest to expand its volume. The process of expanding MariaDB standalone is same as MariaDB cluster.

Prepare MariaDB Database

At first verify that your cluster has a storage class, that supports volume expansion. Let’s check,

$ kubectl get storageclass
NAME                  PROVISIONER             RECLAIMPOLICY   VOLUMEBINDINGMODE      ALLOWVOLUMEEXPANSION   AGE
standard (default)    rancher.io/local-path   Delete          WaitForFirstConsumer   false                  69s
topolvm-provisioner   topolvm.cybozu.com      Delete          WaitForFirstConsumer   true                   37s

We can see from the output the topolvm-provisioner storage class has ALLOWVOLUMEEXPANSION field as true. So, this storage class supports volume expansion. We will use this storage class. You can install topolvm from here.

Now, we are going to deploy a MariaDB database of 3 replicas with version 10.5.23.

Deploy MariaDB

In this section, we are going to deploy a MariaDB Cluster with 1GB volume. Then, in the next section we will expand its volume to 2GB using MariaDBOpsRequest CRD. Below is the YAML of the MariaDB CR that we are going to create,

apiVersion: kubedb.com/v1
kind: MariaDB
metadata:
  name: sample-mariadb
  namespace: demo
spec:
  version: "10.5.23"
  replicas: 3
  storageType: Durable
  storage:
    storageClassName: "topolvm-provisioner"
    accessModes:
    - ReadWriteOnce
    resources:
      requests:
        storage: 1Gi
  deletionPolicy: WipeOut

Let’s create the MariaDB CR we have shown above,

$ kubectl create -f https://github.com/kubedb/docs/raw/v2024.8.2-rc.2/docs/guides/mariadb/volume-expansion/volume-expansion/example/sample-mariadb.yaml
mariadb.kubedb.com/sample-mariadb created

Now, wait until sample-mariadb has status Ready. i.e,

$ kubectl get mariadb -n demo
NAME             VERSION   STATUS   AGE
sample-mariadb   10.5.23    Ready    5m4s

Let’s check volume size from petset, and from the persistent volume,

$ kubectl get sts -n demo sample-mariadb -o json | jq '.spec.volumeClaimTemplates[].spec.resources.requests.storage'
"1Gi"

$ kubectl get pv -n demo
NAME                                       CAPACITY   ACCESS MODES   RECLAIM POLICY   STATUS   CLAIM                        STORAGECLASS          REASON   AGE
pvc-331335d1-c8e0-4b73-9dab-dae57920e997   1Gi        RWO            Delete           Bound    demo/data-sample-mariadb-0   topolvm-provisioner            63s
pvc-b90179f8-c40a-4273-ad77-74ca8470b782   1Gi        RWO            Delete           Bound    demo/data-sample-mariadb-1   topolvm-provisioner            62s
pvc-f72411a4-80d5-4d32-b713-cb30ec662180   1Gi        RWO            Delete           Bound    demo/data-sample-mariadb-2   topolvm-provisioner            62s

You can see the petset has 1GB storage, and the capacity of all the persistent volumes are also 1GB.

We are now ready to apply the MariaDBOpsRequest CR to expand the volume of this database.

Volume Expansion

Here, we are going to expand the volume of the MariaDB cluster.

Create MariaDBOpsRequest

In order to expand the volume of the database, we have to create a MariaDBOpsRequest CR with our desired volume size. Below is the YAML of the MariaDBOpsRequest CR that we are going to create,

apiVersion: ops.kubedb.com/v1alpha1
kind: MariaDBOpsRequest
metadata:
  name: md-online-volume-expansion
  namespace: demo
spec:
  type: VolumeExpansion  
  databaseRef:
    name: sample-mariadb
  volumeExpansion:   
    mode: "Online"
    mariadb: 2Gi

Here,

spec.databaseRef.name specifies that we are performing volume expansion operation on sample-mariadb database.
spec.type specifies that we are performing VolumeExpansion on our database.
spec.volumeExpansion.mariadb specifies the desired volume size.
spec.volumeExpansion.mode specifies the desired volume expansion mode (Online or Offline). Storageclass topolvm-provisioner supports Online volume expansion.

Note: If the Storageclass you are using doesn’t support Online Volume Expansion, Try offline volume expansion by using spec.volumeExpansion.mode:"Offline".

Let’s create the MariaDBOpsRequest CR we have shown above,

$ kubectl apply -f https://github.com/kubedb/docs/raw/v2024.8.2-rc.2/docs/guides/mariadb/volume-expansion/volume-expansion/example/online-volume-expansion.yaml
mariadbopsrequest.ops.kubedb.com/md-online-volume-expansion created

Verify MariaDB volume expanded successfully

If everything goes well, KubeDB Enterprise operator will update the volume size of MariaDB object and related PetSets and Persistent Volumes.

Let’s wait for MariaDBOpsRequest to be Successful. Run the following command to watch MariaDBOpsRequest CR,

$ kubectl get mariadbopsrequest -n demo
NAME                         TYPE              STATUS       AGE
md-online-volume-expansion   VolumeExpansion   Successful   96s

We can see from the above output that the MariaDBOpsRequest has succeeded. If we describe the MariaDBOpsRequest we will get an overview of the steps that were followed to expand the volume of the database.

$ kubectl describe mariadbopsrequest -n demo md-online-volume-expansion
Name:         md-online-volume-expansion
Namespace:    demo
Labels:       <none>
Annotations:  API Version:  ops.kubedb.com/v1alpha1
Kind:         MariaDBOpsRequest
Metadata:
  UID:               09a119aa-4f2a-4cb4-b620-2aa3a514df11
Spec:
  Database Ref:
    Name:  sample-mariadb
  Type:    VolumeExpansion
  Volume Expansion:
    Mariadb:  2Gi
    Mode:     Online
Status:
  Conditions:
    Last Transition Time:  2022-01-07T06:38:29Z
    Message:               Controller has started to Progress the MariaDBOpsRequest: demo/md-online-volume-expansion
    Observed Generation:   1
    Reason:                OpsRequestProgressingStarted
    Status:                True
    Type:                  Progressing
    Last Transition Time:  2022-01-07T06:39:49Z
    Message:               Online Volume Expansion performed successfully in MariaDB pod for MariaDBOpsRequest: demo/md-online-volume-expansion
    Observed Generation:   1
    Reason:                SuccessfullyVolumeExpanded
    Status:                True
    Type:                  VolumeExpansion
    Last Transition Time:  2022-01-07T06:39:49Z
    Message:               Controller has successfully expand the volume of MariaDB demo/md-online-volume-expansion
    Observed Generation:   1
    Reason:                OpsRequestProcessedSuccessfully
    Status:                True
    Type:                  Successful
  Observed Generation:     3
  Phase:                   Successful
Events:
  Type    Reason      Age   From                        Message
  ----    ------      ----  ----                        -------
  Normal  Starting    2m1s  KubeDB Enterprise Operator  Start processing for MariaDBOpsRequest: demo/md-online-volume-expansion
  Normal  Starting    2m1s  KubeDB Enterprise Operator  Pausing MariaDB databse: demo/sample-mariadb
  Normal  Successful  2m1s  KubeDB Enterprise Operator  Successfully paused MariaDB database: demo/sample-mariadb for MariaDBOpsRequest: md-online-volume-expansion
  Normal  Successful  41s   KubeDB Enterprise Operator  Online Volume Expansion performed successfully in MariaDB pod for MariaDBOpsRequest: demo/md-online-volume-expansion
  Normal  Starting    41s   KubeDB Enterprise Operator  Updating MariaDB storage
  Normal  Successful  41s   KubeDB Enterprise Operator  Successfully Updated MariaDB storage
  Normal  Starting    41s   KubeDB Enterprise Operator  Resuming MariaDB database: demo/sample-mariadb
  Normal  Successful  41s   KubeDB Enterprise Operator  Successfully resumed MariaDB database: demo/sample-mariadb
  Normal  Successful  41s   KubeDB Enterprise Operator  Controller has Successfully expand the volume of MariaDB: demo/sample-mariadb

Now, we are going to verify from the Petset, and the Persistent Volumes whether the volume of the database has expanded to meet the desired state, Let’s check,

$ kubectl get sts -n demo sample-mariadb -o json | jq '.spec.volumeClaimTemplates[].spec.resources.requests.storage'
"2Gi"

$ kubectl get pv -n demo
NAME                                       CAPACITY   ACCESS MODES   RECLAIM POLICY   STATUS   CLAIM                        STORAGECLASS          REASON   AGE
pvc-331335d1-c8e0-4b73-9dab-dae57920e997   2Gi        RWO            Delete           Bound    demo/data-sample-mariadb-0   topolvm-provisioner            12m
pvc-b90179f8-c40a-4273-ad77-74ca8470b782   2Gi        RWO            Delete           Bound    demo/data-sample-mariadb-1   topolvm-provisioner            12m
pvc-f72411a4-80d5-4d32-b713-cb30ec662180   2Gi        RWO            Delete           Bound    demo/data-sample-mariadb-2   topolvm-provisioner            12m

The above output verifies that we have successfully expanded the volume of the MariaDB database.

Cleaning Up

To clean up the Kubernetes resources created by this tutorial, run:

$ kubectl delete mariadb -n demo sample-mariadb
$ kubectl delete mariadbopsrequest -n demo md-online-volume-expansion

KubeDB

Stash

KubeVault

Voyager

ConfigSyncer

Guard

RESOURCES

Druid

Elasticsearch

FerretDB

Kafka

MariaDB

Memcached

Microsoft SQL Server

MongoDB

MySQL

OpenSearch

PerconaXtraDB

PgBouncer

Pgpool

PostgreSQL

ProxySQL

RabbitMQ

Redis

SingleStore

Solr

ZooKeeper