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Vertical Scale MySQL Group Replication
This guide will show you how to use KubeDB enterprise operator to update the resources of the members of a MySQL Group Replication.
Before You Begin
At first, you need to have a Kubernetes cluster, and the
kubectlcommand-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
KubeDBcommunity and enterprise operator in your cluster following the steps here.You should be familiar with the following
KubeDBconcepts:
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/scaling/vertical-scaling/group-replication/yamls directory of kubedb/doc repository.
Apply Vertical Scaling on MySQL 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 vertical scaling on it.
Prepare Group Replication
At first, we are going to deploy a group replication server using a supported MySQL version. Then, we are going to update the resources of the members through vertical scaling.
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 DB_IMAGE DEPRECATED AGE
5.7.25-v2 5.7.25 kubedb/mysql:5.7.25-v2 3h55m
5.7.36 5.7.29 kubedb/mysql:5.7.36 3h55m
5.7.36 5.7.31 kubedb/mysql:5.7.36 3h55m
5.7.36 5.7.33 kubedb/mysql:5.7.36 3h55m
8.0.14-v2 8.0.14 kubedb/mysql:8.0.14-v2 3h55m
8.0.20-v1 8.0.20 kubedb/mysql:8.0.20-v1 3h55m
8.0.27 8.0.21 kubedb/mysql:8.0.27 3h55m
8.0.27 8.0.27 kubedb/mysql:8.0.27 3h55m
8.0.3-v2 8.0.3 kubedb/mysql:8.0.3-v2 3h55m
The version above that does not show DEPRECATED true is supported by KubeDB for MySQL. You can use any non-deprecated version. Here, we are going to create a MySQL Group Replication using non-deprecated MySQL version 8.0.27.
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 update the resources of the members using vertical scaling. 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/v2021.12.21/docs/guides/mysql/scaling/vertical-scaling/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.
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
Every 3.0s: kubectl get my -n demo my-group suaas-appscode: Tue Jun 30 22:43:57 2020
NAME VERSION STATUS AGE
my-group 8.0.27 Running 16m
$ watch -n 3 kubectl get sts -n demo my-group
Every 3.0s: kubectl get sts -n demo my-group Every 3.0s: kubectl get sts -n demo my-group suaas-appscode: Tue Jun 30 22:44:35 2020
NAME READY AGE
my-group 3/3 16m
$ watch -n 3 kubectl get pod -n demo -l app.kubernetes.io/name=mysqls.kubedb.com,app.kubernetes.io/instance=my-group
Every 3.0s: kubectl get pod -n demo -l app.kubernetes.io/name=mysqls.kubedb.com suaas-appscode: Tue Jun 30 22:45:33 2020
NAME READY STATUS RESTARTS AGE
my-group-0 2/2 Running 0 17m
my-group-1 2/2 Running 0 14m
my-group-2 2/2 Running 0 11m
Let’s check one of the StatefulSet’s pod containers resources,
$ kubectl get pod -n demo my-group-0 -o json | jq '.spec.containers[1].resources'
{}
You can see that the Pod has empty resources that mean the scheduler will choose a random node to place the container of the Pod on by default. Now, we are ready to apply the vertical scale on this group replication.
Vertical Scaling
Here, we are going to update the resources of the database cluster to meet up with the desired resources after scaling.
Create MySQLOpsRequest:
In order to update the resources of your database cluster, you have to create a MySQLOpsRequest cr with your desired resources after scaling. Below is the YAML of the MySQLOpsRequest cr that we are going to create,
apiVersion: ops.kubedb.com/v1alpha1
kind: MySQLOpsRequest
metadata:
name: my-scale-group
namespace: demo
spec:
type: VerticalScaling
databaseRef:
name: my-group
verticalScaling:
mysql:
requests:
memory: "1200Mi"
cpu: "0.7"
limits:
memory: "1200Mi"
cpu: "0.7"
Here,
spec.databaseRef.namespecifies that we are performing operation onmy-groupMySQLdatabase.spec.typespecifies that we are performingVerticalScalingon our database.spec.VerticalScaling.mysqlspecifies the expected mysql container resources after scaling.
Let’s create the MySQLOpsRequest cr we have shown above,
$ kubectl apply -f https://github.com/kubedb/docs/raw/v2021.12.21/docs/guides/mysql/scaling/vertical-scaling/group-replication/yamls/my-scale-group.yaml
mysqlopsrequest.ops.kubedb.com/my-scale-group created
Verify MySQL Group Replication resources updated successfully:
If everything goes well, KubeDB enterprise operator will update the resources of the StatefulSet’s Pod containers. After a successful scaling process is done, the KubeDB enterprise operator updates the resources of the MySQL cluster.
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-scale-group
Every 3.0s: kubectl get myops -n demo my-sc... suaas-appscode: Wed Aug 12 16:49:21 2020
NAME TYPE STATUS AGE
my-scale-group VerticalScaling Successful 4m53s
You can see from the above output that the MySQLOpsRequest has succeeded. If we describe the MySQLOpsRequest, we shall see that the resources of the members of the MySQL group replication are updated.
$ kubectl describe myops -n demo my-scale-group
Name: my-scale-group
Namespace: demo
Labels: <none>
Annotations: <none>
API Version: ops.kubedb.com/v1alpha1
Kind: MySQLOpsRequest
Metadata:
Creation Timestamp: 2021-03-10T10:54:24Z
Generation: 2
Manager: kubectl-client-side-apply
Operation: Update
Time: 2021-03-10T10:54:24Z
API Version: ops.kubedb.com/v1alpha1
Fields Type: FieldsV1
Manager: kubedb-enterprise
Operation: Update
Time: 2021-03-10T10:56:19Z
Resource Version: 1083654
Self Link: /apis/ops.kubedb.com/v1alpha1/namespaces/demo/mysqlopsrequests/my-scale-group
UID: 92ace405-666c-45da-aaa1-fd3d079c187d
Spec:
Database Ref:
Name: my-group
Stateful Set Ordinal: 0
Type: VerticalScaling
Vertical Scaling:
Mysql:
Limits:
Cpu: 0.7
Memory: 1200Mi
Requests:
Cpu: 0.7
Memory: 1200Mi
Status:
Conditions:
Last Transition Time: 2021-03-10T10:54:24Z
Message: Controller has started to Progress the MySQLOpsRequest: demo/my-scale-group
Observed Generation: 2
Reason: OpsRequestProgressingStarted
Status: True
Type: Progressing
Last Transition Time: 2021-03-10T10:54:24Z
Message: Vertical scaling started in MySQL: demo/my-group for MySQLOpsRequest: my-scale-group
Observed Generation: 2
Reason: VerticalScalingStarted
Status: True
Type: Scaling
Last Transition Time: 2021-03-10T10:56:19Z
Message: Vertical scaling performed successfully in MySQL: demo/my-group for MySQLOpsRequest: my-scale-group
Observed Generation: 2
Reason: SuccessfullyPerformedVerticalScaling
Status: True
Type: VerticalScaling
Last Transition Time: 2021-03-10T10:56:19Z
Message: Controller has successfully scaled the MySQL demo/my-scale-group
Observed Generation: 2
Reason: OpsRequestProcessedSuccessfully
Status: True
Type: Successful
Observed Generation: 3
Phase: Successful
Events:
Type Reason Age From Message
---- ------ ---- ---- -------
Normal Starting 7m46s KubeDB Enterprise Operator Start processing for MySQLOpsRequest: demo/my-scale-group
Normal Starting 7m46s KubeDB Enterprise Operator Pausing MySQL databse: demo/my-group
Normal Successful 7m46s KubeDB Enterprise Operator Successfully paused MySQL database: demo/my-group for MySQLOpsRequest: my-scale-group
Normal Starting 7m46s KubeDB Enterprise Operator Vertical scaling started in MySQL: demo/my-group for MySQLOpsRequest: my-scale-group
Normal Starting 7m41s KubeDB Enterprise Operator Restarting Pod: demo/my-group-1
Normal Starting 7m1s KubeDB Enterprise Operator Restarting Pod: demo/my-group-2
Normal Starting 6m31s KubeDB Enterprise Operator Restarting Pod (master): demo/my-group-0
Normal Successful 5m51s KubeDB Enterprise Operator Vertical scaling performed successfully in MySQL: demo/my-group for MySQLOpsRequest: my-scale-group
Normal Starting 5m51s KubeDB Enterprise Operator Resuming MySQL database: demo/my-group
Normal Successful 5m51s KubeDB Enterprise Operator Successfully resumed MySQL database: demo/my-group
Normal Successful 5m51s KubeDB Enterprise Operator Controller has Successfully scaled the MySQL database: demo/my-group
Now, we are going to verify whether the resources of the members of the cluster have updated to meet up the desired state, Let’s check,
$ kubectl get pod -n demo my-group-0 -o json | jq '.spec.containers[1].resources'
{
"limits": {
"cpu": "700m",
"memory": "1200Mi"
},
"requests": {
"cpu": "700m",
"memory": "1200Mi"
}
}
The above output verifies that we have successfully updated the resources of the MySQL group replication.
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-scale-group