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This is an Enterprise-only feature. Please install
KubeDB Enterprise Edition to try this feature.
PerconaXtraDB Volume Expansion
This guide will show you how to use KubeDB Enterprise operator to expand the volume of a PerconaXtraDB.
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 PerconaXtraDB
Here, we are going to deploy a PerconaXtraDB cluster using a supported version by KubeDB operator. Then we are going to apply PerconaXtraDBOpsRequest to expand its volume. The process of expanding PerconaXtraDB standalone is same as PerconaXtraDB cluster.
Prepare PerconaXtraDB 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 PerconaXtraDB database of 3 replicas with version 8.0.26.
Deploy PerconaXtraDB
In this section, we are going to deploy a PerconaXtraDB Cluster with 1GB volume. Then, in the next section we will expand its volume to 2GB using PerconaXtraDBOpsRequest CRD. Below is the YAML of the PerconaXtraDB CR that we are going to create,
apiVersion: kubedb.com/v1alpha2
kind: PerconaXtraDB
metadata:
name: sample-pxc
namespace: demo
spec:
version: "8.0.26"
replicas: 3
storageType: Durable
storage:
storageClassName: "topolvm-provisioner"
accessModes:
- ReadWriteOnce
resources:
requests:
storage: 1Gi
terminationPolicy: WipeOut
Let’s create the PerconaXtraDB CR we have shown above,
$ kubectl create -f https://github.com/kubedb/docs/raw/v2023.01.31/docs/guides/percona-xtradb/volume-expansion/volume-expansion/example/sample-pxc.yaml
perconaxtradb.kubedb.com/sample-pxc created
Now, wait until sample-pxc has status Ready. i.e,
$ kubectl get perconaxtradb -n demo
NAME VERSION STATUS AGE
sample-pxc 8.0.26 Ready 5m4s
Let’s check volume size from statefulset, and from the persistent volume,
$ kubectl get sts -n demo sample-pxc -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-pxc-0 topolvm-provisioner 63s
pvc-b90179f8-c40a-4273-ad77-74ca8470b782 1Gi RWO Delete Bound demo/data-sample-pxc-1 topolvm-provisioner 62s
pvc-f72411a4-80d5-4d32-b713-cb30ec662180 1Gi RWO Delete Bound demo/data-sample-pxc-2 topolvm-provisioner 62s
You can see the statefulset has 1GB storage, and the capacity of all the persistent volumes are also 1GB.
We are now ready to apply the PerconaXtraDBOpsRequest CR to expand the volume of this database.
Volume Expansion
Here, we are going to expand the volume of the PerconaXtraDB cluster.
Create PerconaXtraDBOpsRequest
In order to expand the volume of the database, we have to create a PerconaXtraDBOpsRequest CR with our desired volume size. Below is the YAML of the PerconaXtraDBOpsRequest CR that we are going to create,
apiVersion: ops.kubedb.com/v1alpha1
kind: PerconaXtraDBOpsRequest
metadata:
name: px-online-volume-expansion
namespace: demo
spec:
type: VolumeExpansion
databaseRef:
name: sample-pxc
volumeExpansion:
mode: "Online"
perconaxtradb: 2Gi
Here,
spec.databaseRef.name specifies that we are performing volume expansion operation on sample-pxc database.spec.type specifies that we are performing VolumeExpansion on our database.spec.volumeExpansion.perconaxtradb 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 PerconaXtraDBOpsRequest CR we have shown above,
$ kubectl apply -f https://github.com/kubedb/docs/raw/v2023.01.31/docs/guides/percona-xtradb/volume-expansion/volume-expansion/example/online-volume-expansion.yaml
perconaxtradbopsrequest.ops.kubedb.com/px-online-volume-expansion created
Verify PerconaXtraDB volume expanded successfully
If everything goes well, KubeDB Enterprise operator will update the volume size of PerconaXtraDB object and related StatefulSets and Persistent Volumes.
Let’s wait for PerconaXtraDBOpsRequest to be Successful. Run the following command to watch PerconaXtraDBOpsRequest CR,
$ kubectl get perconaxtradbopsrequest -n demo
NAME TYPE STATUS AGE
px-online-volume-expansion VolumeExpansion Successful 96s
We can see from the above output that the PerconaXtraDBOpsRequest has succeeded. If we describe the PerconaXtraDBOpsRequest we will get an overview of the steps that were followed to expand the volume of the database.
$ kubectl describe perconaxtradbopsrequest -n demo px-online-volume-expansion
Name: px-online-volume-expansion
Namespace: demo
Labels: <none>
Annotations: API Version: ops.kubedb.com/v1alpha1
Kind: PerconaXtraDBOpsRequest
Metadata:
UID: 09a119aa-4f2a-4cb4-b620-2aa3a514df11
Spec:
Database Ref:
Name: sample-pxc
Type: VolumeExpansion
Volume Expansion:
PerconaXtraDB: 2Gi
Mode: Online
Status:
Conditions:
Last Transition Time: 2022-01-07T06:38:29Z
Message: Controller has started to Progress the PerconaXtraDBOpsRequest: demo/px-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 PerconaXtraDB pod for PerconaXtraDBOpsRequest: demo/px-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 PerconaXtraDB demo/px-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 PerconaXtraDBOpsRequest: demo/px-online-volume-expansion
Normal Starting 2m1s KubeDB Enterprise Operator Pausing PerconaXtraDB databse: demo/sample-pxc
Normal Successful 2m1s KubeDB Enterprise Operator Successfully paused PerconaXtraDB database: demo/sample-pxc for PerconaXtraDBOpsRequest: px-online-volume-expansion
Normal Successful 41s KubeDB Enterprise Operator Online Volume Expansion performed successfully in PerconaXtraDB pod for PerconaXtraDBOpsRequest: demo/px-online-volume-expansion
Normal Starting 41s KubeDB Enterprise Operator Updating PerconaXtraDB storage
Normal Successful 41s KubeDB Enterprise Operator Successfully Updated PerconaXtraDB storage
Normal Starting 41s KubeDB Enterprise Operator Resuming PerconaXtraDB database: demo/sample-pxc
Normal Successful 41s KubeDB Enterprise Operator Successfully resumed PerconaXtraDB database: demo/sample-pxc
Normal Successful 41s KubeDB Enterprise Operator Controller has Successfully expand the volume of PerconaXtraDB: demo/sample-pxc
Now, we are going to verify from the Statefulset, 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-pxc -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-pxc-0 topolvm-provisioner 12m
pvc-b90179f8-c40a-4273-ad77-74ca8470b782 2Gi RWO Delete Bound demo/data-sample-pxc-1 topolvm-provisioner 12m
pvc-f72411a4-80d5-4d32-b713-cb30ec662180 2Gi RWO Delete Bound demo/data-sample-pxc-2 topolvm-provisioner 12m
The above output verifies that we have successfully expanded the volume of the PerconaXtraDB database.
Cleaning Up
To clean up the Kubernetes resources created by this tutorial, run:
$ kubectl delete perconaxtradb -n demo sample-pxc
$ kubectl delete perconaxtradbopsrequest -n demo px-online-volume-expansion
