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Upgrade minor version of MySQL Group Replication

This guide will show you how to use KubeDB enterprise operator to upgrade the minor version of MySQL Group Replication.

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. If you do not already have a cluster, you can create one by using kind.
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

Note: YAML files used in this tutorial are stored in docs/guides/mysql/upgrading/minorversion/group-replication/yamls directory of kubedb/docs repository.

Apply Version Upgrading on Group Replication

Here, we are going to deploy a MySQL group replication using a supported version by KubeDB operator. Then we are going to apply upgrading on it.

Prepare Group Replication

At first, we are going to deploy a group replication using supported that MySQL version whether it is possible to upgrade from this version to another. In the next two sections, we are going to find out the supported version and version upgrade constraints.

Find supported MySQL Version:

When you have installed KubeDB, it has created MySQLVersion CR for all supported MySQL versions. Let’s check the supported MySQL versions,

$ kubectl get mysqlversion
NAME            VERSION   DISTRIBUTION   DB_IMAGE                    DEPRECATED   AGE
5.7.35-v1       5.7.35    Official       mysql:5.7.35                             13d
5.7.36          5.7.36    Official       mysql:5.7.36                             13d
8.0.17          8.0.17    Official       mysql:8.0.17                             13d
8.0.27          8.0.27    Official       mysql:8.0.27                             13d
8.0.27-innodb   8.0.27    MySQL          mysql/mysql-server:8.0.27                13d
8.0.29          8.0.29    Official       mysql:8.0.29                             13d
8.0.3-v4        8.0.3     Official       mysql:8.0.3                              13d

The version above that does not show DEPRECATED true is supported by KubeDB for MySQL. You can use any non-deprecated version. Now, we are going to select a non-deprecated version from MySQLVersion for MySQL group replication that will be possible to upgrade from this version to another version. In the next section, we are going to verify version upgrade constraints.

Check Upgrade Constraints:

Database version upgrade constraints is a constraint that shows whether it is possible or not possible to upgrade from one version to another. Let’s check the version upgrade constraints of MySQL 8.0.27,

$ kubectl get mysqlversion 8.0.27 -o yaml
apiVersion: catalog.kubedb.com/v1alpha1
kind: MySQLVersion
metadata:
  annotations:
    meta.helm.sh/release-name: kubedb-catalog
    meta.helm.sh/release-namespace: kubedb
  creationTimestamp: "2022-06-16T13:52:58Z"
  generation: 1
  labels:
    app.kubernetes.io/instance: kubedb-catalog
    app.kubernetes.io/managed-by: Helm
    app.kubernetes.io/name: kubedb-catalog
    app.kubernetes.io/version: v2022.03.28
    helm.sh/chart: kubedb-catalog-v2022.03.28
  name: 8.0.27
  resourceVersion: "1092466"
  uid: fa68b792-a8b3-47a3-a32e-66a47f79c177
spec:
  coordinator:
    image: kubedb/mysql-coordinator:v0.5.0
  db:
    image: mysql:8.0.27
  distribution: Official
  exporter:
    image: kubedb/mysqld-exporter:v0.13.1
  initContainer:
    image: kubedb/mysql-init:8.0.26-v1
  podSecurityPolicies:
    databasePolicyName: mysql-db
  replicationModeDetector:
    image: kubedb/replication-mode-detector:v0.13.0
  stash:
    addon:
      backupTask:
        name: mysql-backup-8.0.21
      restoreTask:
        name: mysql-restore-8.0.21
  upgradeConstraints:
    denylist:
      groupReplication:
      - < 8.0.27
      standalone:
      - < 8.0.27
  version: 8.0.27

The above spec.upgradeConstraints.denylist of 8.0.27 is showing that upgrading below version of 8.0.27 is not possible for both group replication and standalone. That means, it is possible to upgrade any version above 8.0.27. Here, we are going to create a MySQL Group Replication using MySQL 8.0.27. Then we are going to upgrade this version to 8.0.29.

Deploy MySQL Group Replication:

In this section, we are going to deploy a MySQL group replication with 3 members. Then, in the next section we will upgrade the version of the members using upgrading. Below is the YAML of the MySQL cr that we are going to create,

apiVersion: kubedb.com/v1alpha2
kind: MySQL
metadata:
  name: my-group
  namespace: demo
spec:
  version: "8.0.27"
  replicas: 3
  topology:
    mode: GroupReplication
    group:
      name: "dc002fc3-c412-4d18-b1d4-66c1fbfbbc9b"
  storageType: Durable
  storage:
    storageClassName: "standard"
    accessModes:
      - ReadWriteOnce
    resources:
      requests:
        storage: 1Gi
  terminationPolicy: WipeOut

Let’s create the MySQL cr we have shown above,

$ kubectl create -f https://github.com/kubedb/docs/raw/v2022.08.08/docs/guides/mysql/upgrading/minorversion/group-replication/yamls/group_replication.yaml
mysql.kubedb.com/my-group created

Wait for the cluster to be ready:

KubeDB operator watches for MySQL objects using Kubernetes API. When a MySQL object is created, KubeDB operator will create a new StatefulSet, Services, and Secrets, etc. A secret called my-group-auth (format: {mysql-object-name}-auth) will be created storing the password for mysql superuser. Now, watch MySQL is going to Running state and also watch StatefulSet and its pod is created and going to Running state,

$ watch -n 3 kubectl get my -n demo my-group


NAME       VERSION   STATUS         AGE
my-group   8.0.27    Ready          5m

$ watch -n 3 kubectl get sts -n demo my-group

NAME       READY   AGE
my-group   3/3     7m12s

$ watch -n 3 kubectl get pod -n demo -l app.kubernetes.io/name=mysqls.kubedb.com,app.kubernetes.io/instance=my-group

NAME         READY   STATUS    RESTARTS   AGE
my-group-0   2/2     Running   0          11m
my-group-1   2/2     Running   0          9m53s
my-group-2   2/2     Running   0          6m48s

Let’s verify the MySQL, the StatefulSet and its Pod image version,

$ kubectl get my -n demo my-group -o=jsonpath='{.spec.version}{"\n"}'
8.0.27

$ kubectl get sts -n demo -l app.kubernetes.io/name=mysqls.kubedb.com,app.kubernetes.io/instance=my-group -o json | jq '.items[].spec.template.spec.containers[1].image'
"mysql:8.0.27"

$ kubectl get pod -n demo -l app.kubernetes.io/name=mysqls.kubedb.com,app.kubernetes.io/instance=my-group -o json | jq '.items[].spec.containers[1].image'
"mysql:8.0.27"
"mysql:8.0.27"
"mysql:8.0.27"

Let’s also verify that the StatefulSet’s pods have joined into the group replication,

$ kubectl get secrets -n demo my-group-auth -o jsonpath='{.data.\username}' | base64 -d
root

$ kubectl get secrets -n demo my-group-auth -o jsonpath='{.data.\password}' | base64 -d
XbUHi_Cp&SLSXTmo

$ kubectl exec -it -n demo my-group-0 -c mysql -- mysql -u root --password='XbUHi_Cp&SLSXTmo' --host=my-group-0.my-group-pods.demo -e "select * from performance_schema.replication_group_members"
mysql: [Warning] Using a password on the command line interface can be insecure.
+---------------------------+--------------------------------------+-----------------------------------+-------------+--------------+-------------+----------------+----------------------------+
| CHANNEL_NAME              | MEMBER_ID                            | MEMBER_HOST                       | MEMBER_PORT | MEMBER_STATE | MEMBER_ROLE | MEMBER_VERSION | MEMBER_COMMUNICATION_STACK |
+---------------------------+--------------------------------------+-----------------------------------+-------------+--------------+-------------+----------------+----------------------------+
| group_replication_applier | 6e7f3cc4-f84d-11ec-adcd-d23a2a3ef58a | my-group-1.my-group-pods.demo.svc |        3306 | ONLINE       | SECONDARY   | 8.0.27         | XCom                       |
| group_replication_applier | 70c60c5b-f84d-11ec-821b-4af781e22a9f | my-group-2.my-group-pods.demo.svc |        3306 | ONLINE       | SECONDARY   | 8.0.27         | XCom                       |
| group_replication_applier | 71fdc498-f84d-11ec-a6f3-b2ee89425e4f | my-group-0.my-group-pods.demo.svc |        3306 | ONLINE       | PRIMARY     | 8.0.27         | XCom                       |
+---------------------------+--------------------------------------+-----------------------------------+-------------+--------------+-------------+----------------+----------------------------+

We are ready to apply upgrading on this MySQL group replication.

Upgrade

Here, we are going to upgrade the MySQL group replication from 8.0.27 to 8.0.29.

Create MySQLOpsRequest:

To upgrade your database cluster, you have to create a MySQLOpsRequest cr with your desired version that supported by KubeDB. Below is the YAML of the MySQLOpsRequest cr that we are going to create,

apiVersion: ops.kubedb.com/v1alpha1
kind: MySQLOpsRequest
metadata:
  name: my-upgrade-minor-group
  namespace: demo
spec:
  type: Upgrade
  databaseRef:
    name: my-group
  upgrade:
    targetVersion: "8.0.29"

Here,

spec.databaseRef.name specifies that we are performing operation on my-group MySQL database.
spec.type specifies that we are going to perform Upgrade on our database.
spec.upgrade.targetVersion specifies expected version 8.0.29 after upgrading.

Let’s create the MySQLOpsRequest cr we have shown above,

$ kubectl apply -f https://github.com/kubedb/docs/raw/v2022.08.08/docs/guides/mysql/upgrading/minorversion/group-replication/yamls/upgrade_minor_version_group.yaml
mysqlopsrequest.ops.kubedb.com/my-upgrade-minor-group created

Verify MySQL version upgraded successfully:

If everything goes well, KubeDB enterprise operator will update the image of MySQL, StatefulSet, and its Pod.

At first, we will wait for MySQLOpsRequest to be successful. Run the following command to watch MySQlOpsRequest cr,

$ watch -n 3 kubectl get myops -n demo my-upgrade-minor-group
NAME                     TYPE      STATUS       AGE
my-upgrade-minor-group   Upgrade   Successful   5m26s

You can see from the above output that the MySQLOpsRequest has succeeded. If we describe the MySQLOpsRequest, we shall see that the MySQL group replication is updated with the new version and the StatefulSet is created with a new image.

$ kubectl describe myops -n demo my-upgrade-minor-group

Name:         my-upgrade-minor-group
Namespace:    demo
Labels:       <none>
Annotations:  <none>
API Version:  ops.kubedb.com/v1alpha1
Kind:         MySQLOpsRequest
Metadata:
  Creation Timestamp:  2022-06-30T08:26:36Z
    Manager:         kubedb-ops-manager
    Operation:       Update
    Time:            2022-06-30T08:26:36Z
  Resource Version:  1712998
  UID:               3a84eb20-ba5f-4ec6-969a-bfdb7b072b5a
Spec:
  Database Ref:
    Name:  my-group
  Type:    Upgrade
  Upgrade:
    Target Version:  8.0.29
Status:
  Conditions:
    Last Transition Time:  2022-06-30T08:26:36Z
    Message:               Controller has started to Progress the MySQLOpsRequest: demo/my-upgrade-minor-group
    Observed Generation:   1
    Reason:                OpsRequestProgressingStarted
    Status:                True
    Type:                  Progressing
    Last Transition Time:  2022-06-30T08:26:36Z
    Message:               MySQL version UpgradeFunc stated for MySQLOpsRequest: demo/my-upgrade-minor-group
    Observed Generation:   1
    Reason:                DatabaseVersionUpgradingStarted
    Status:                True
    Type:                  Upgrading
    Last Transition Time:  2022-06-30T08:31:26Z
    Message:               Image successfully updated in MySQL: demo/my-group for MySQLOpsRequest: my-upgrade-minor-group 
    Observed Generation:   1
    Reason:                SuccessfullyUpgradedDatabaseVersion
    Status:                True
    Type:                  UpgradeVersion
    Last Transition Time:  2022-06-30T08:31:27Z
    Message:               Controller has successfully upgraded the MySQL demo/my-upgrade-minor-group
    Observed Generation:   1
    Reason:                OpsRequestProcessedSuccessfully
    Status:                True
    Type:                  Successful
  Observed Generation:     3
  Phase:                   Successful
Events:
  Type    Reason      Age   From                        Message
  ----    ------      ----  ----                        -------
  Normal  Starting    33m   KubeDB Enterprise Operator  Start processing for MySQLOpsRequest: demo/my-upgrade-minor-group
  Normal  Starting    33m   KubeDB Enterprise Operator  Pausing MySQL databse: demo/my-group
  Normal  Successful  33m   KubeDB Enterprise Operator  Successfully paused MySQL database: demo/my-group for MySQLOpsRequest: my-upgrade-minor-group
  Normal  Starting    33m   KubeDB Enterprise Operator  Upgrading MySQL images: demo/my-group for MySQLOpsRequest: my-upgrade-minor-group
  Normal  Starting    33m   KubeDB Enterprise Operator  Restarting Pod: my-group-1/demo
  Normal  Starting    32m   KubeDB Enterprise Operator  Restarting Pod: my-group-2/demo
  Normal  Starting    30m   KubeDB Enterprise Operator  Restarting Pod: my-group-0/demo
  Normal  Successful  29m   KubeDB Enterprise Operator  Image successfully updated in MySQL: demo/my-group for MySQLOpsRequest: my-upgrade-minor-group
  Normal  Starting    29m   KubeDB Enterprise Operator  Resuming MySQL database: demo/my-group
  Normal  Successful  29m   KubeDB Enterprise Operator  Successfully resumed MySQL database: demo/my-group
  Normal  Successful  29m   KubeDB Enterprise Operator  Controller has Successfully upgraded the version of MySQL : demo/my-group

Now, we are going to verify whether the MySQL and StatefulSet and it’s Pod have updated with new image. Let’s check,

$ kubectl get my -n demo my-group -o=jsonpath='{.spec.version}{"\n"}'
5.7.36

$ kubectl get sts -n demo -l app.kubernetes.io/name=mysqls.kubedb.com,app.kubernetes.io/instance=my-group -o json | jq '.items[].spec.template.spec.containers[1].image'
"mysql:8.0.29"

$ kubectl get pod -n demo -l app.kubernetes.io/name=mysqls.kubedb.com,app.kubernetes.io/instance=my-group -o json | jq '.items[].spec.containers[1].image'
"mysql:8.0.29"
"mysql:8.0.29"
"mysql:8.0.29"

Let’s also check the StatefulSet pods have joined the MySQL group replication,

$ kubectl get secrets -n demo my-group-auth -o jsonpath='{.data.\username}' | base64 -d
root

$ kubectl get secrets -n demo my-group-auth -o jsonpath='{.data.\password}' | base64 -d
XbUHi_Cp&SLSXTmo

$ kubectl exec -it -n demo my-group-0 -c mysql -- mysql -u root --password='XbUHi_Cp&SLSXTmo' --host=my-group-0.my-group-pods.demo -e "select * from performance_schema.replication_group_members"
mysql: [Warning] Using a password on the command line interface can be insecure.
+---------------------------+--------------------------------------+-----------------------------------+-------------+--------------+-------------+----------------+----------------------------+
| CHANNEL_NAME              | MEMBER_ID                            | MEMBER_HOST                       | MEMBER_PORT | MEMBER_STATE | MEMBER_ROLE | MEMBER_VERSION | MEMBER_COMMUNICATION_STACK |
+---------------------------+--------------------------------------+-----------------------------------+-------------+--------------+-------------+----------------+----------------------------+
| group_replication_applier | 6e7f3cc4-f84d-11ec-adcd-d23a2a3ef58a | my-group-1.my-group-pods.demo.svc |        3306 | ONLINE       | PRIMARY     | 8.0.29         | XCom                       |
| group_replication_applier | 70c60c5b-f84d-11ec-821b-4af781e22a9f | my-group-2.my-group-pods.demo.svc |        3306 | ONLINE       | SECONDARY   | 8.0.29         | XCom                       |
| group_replication_applier | 71fdc498-f84d-11ec-a6f3-b2ee89425e4f | my-group-0.my-group-pods.demo.svc |        3306 | ONLINE       | SECONDARY   | 8.0.29         | XCom                       |
+---------------------------+--------------------------------------+-----------------------------------+-------------+--------------+-------------+----------------+----------------------------+

You can see above that our MySQL group replication now has updated members. It verifies that we have successfully upgraded our cluster.

Cleaning Up

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

kubectl delete my -n demo my-group
kubectl delete myops -n demo my-upgrade-minor-group

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