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Reconfigure MySQL Cluster Database
This guide will show you how to use KubeDB Enterprise operator to reconfigure a MySQL Cluster.
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.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
Now, we are going to deploy a MySQL Cluster using a supported version by KubeDB operator. Then we are going to apply MySQLOpsRequest to reconfigure its configuration.
Prepare MySQL Cluster
Now, we are going to deploy a MySQL Cluster database with version 8.0.31.
Deploy MySQL
At first, we will create my-config.cnf file containing required configuration settings.
$ cat my-config.cnf
[mysqld]
max_connections = 200
read_buffer_size = 1048576
Here, max_connections is set to 200, whereas the default value is 151. Likewise, read_buffer_size has the deafult value 131072.
Now, we will create a secret with this configuration file.
$ kubectl create secret generic -n demo my-configuration --from-file=./my-config.cnf
secret/my-configuration created
In this section, we are going to create a MySQL object specifying spec.configSecret field to apply this custom configuration. Below is the YAML of the MySQL CR that we are going to create,
apiVersion: kubedb.com/v1alpha2
kind: MySQL
metadata:
name: sample-mysql
namespace: demo
spec:
version: "8.0.31"
topology:
mode: GroupReplication
replicas: 3
configSecret:
name: my-configuration
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/v2023.11.2/docs/guides/mysql/reconfigure/reconfigure-steps/yamls/group-replication.yaml
mysql.kubedb.com/sample-mysql created
apiVersion: kubedb.com/v1alpha2
kind: MySQL
metadata:
name: sample-mysql
namespace: demo
spec:
version: "8.0.31-innodb"
topology:
mode: InnoDBCluster
innoDBCluster:
router:
replicas: 1
replicas: 3
configSecret:
name: my-configuration
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/v2023.11.2/docs/guides/mysql/reconfigure/reconfigure-steps/yamls/innob-cluster.yaml
mysql.kubedb.com/sample-mysql created
apiVersion: kubedb.com/v1alpha2
kind: MySQL
metadata:
name: sample-mysql
namespace: demo
spec:
version: "8.0.31"
topology:
mode: SemiSync
semiSync:
sourceWaitForReplicaCount: 1
sourceTimeout: 23h
errantTransactionRecoveryPolicy: PseudoTransaction
replicas: 3
configSecret:
name: my-configuration
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/v2023.11.2/docs/guides/mysql/reconfigure/reconfigure-steps/yamls/semi-sync.yaml
mysql.kubedb.com/sample-mysql created
apiVersion: kubedb.com/v1alpha2
kind: MySQL
metadata:
name: sample-mysql
namespace: demo
spec:
version: "8.0.31"
configSecret:
name: my-configuration
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/v2023.11.2/docs/guides/mysql/reconfigure/reconfigure-steps/yamls/stand-alone.yaml
mysql.kubedb.com/sample-mysql created
Now, wait until sample-mysql has status Ready. i.e,
$ kubectl get mysql -n demo
NAME VERSION STATUS AGE
sample-mysql 8.0.31 Ready 5m49s
Now, we will check if the database has started with the custom configuration we have provided.
First we need to get the username and password to connect to a mysql instance,
$ kubectl get secrets -n demo sample-mysql-auth -o jsonpath='{.data.\username}' | base64 -d
root
$ kubectl get secrets -n demo sample-mysql-auth -o jsonpath='{.data.\password}' | base64 -d
86TwLJ!2Kpq*vv1y
Now, we will check if the database has started with the custom configuration we have provided.
$ kubectl exec -it -n demo sample-mysql-0 -- bash
mysql -uroot -p$MYSQL_ROOT_PASSWORD
mysql: [Warning] Using a password on the command line interface can be insecure.
Welcome to the MySQL monitor. Commands end with ; or \g.
Your MySQL connection id is 112
Server version: 8.0.31 MySQL Community Server - GPL
Copyright (c) 2000, 2022, Oracle and/or its affiliates.
Oracle is a registered trademark of Oracle Corporation and/or its
affiliates. Other names may be trademarks of their respective
owners.
Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.
mysql> show variables like 'max_connections';
+-----------------+-------+
| Variable_name | Value |
+-----------------+-------+
| max_connections | 200 |
+-----------------+-------+
1 row in set (0.00 sec)
mysql> show variables like 'read_buffer_size';
+------------------+---------+
| Variable_name | Value |
+------------------+---------+
| read_buffer_size | 1048576 |
+------------------+---------+
1 row in set (0.00 sec)
mysql>
As we can see from the configuration of ready mysql, the value of max_connections has been set to 200 and read_buffer_size has been set to 1048576.
Reconfigure using new config secret
Now we will reconfigure this database to set max_connections to 250 and read_buffer_size to 122880.
Now, we will create new file new-my-config.cnf containing required configuration settings.
$ cat new-my-config.cnf
[mysqld]
max_connections = 250
read_buffer_size = 122880
Then, we will create a new secret with this configuration file.
$ kubectl create secret generic -n demo new-my-configuration --from-file=./new-my-config.cnf
secret/new-my-configuration created
Create MySQLOpsRequest
Now, we will use this secret to replace the previous secret using a MySQLOpsRequest CR. The MySQLOpsRequest yaml is given below,
apiVersion: ops.kubedb.com/v1alpha1
kind: MySQLOpsRequest
metadata:
name: myops-reconfigure-config
namespace: demo
spec:
type: Reconfigure
databaseRef:
name: sample-mysql
configuration:
configSecret:
name: new-my-configuration
Here,
spec.databaseRef.namespecifies that we are reconfiguringsample-mysqldatabase.spec.typespecifies that we are performingReconfigureon our database.spec.configuration.configSecret.namespecifies the name of the new secret.
Let’s create the MySQLOpsRequest CR we have shown above,
$ kubectl apply -f https://github.com/kubedb/docs/raw/v2023.11.2/docs/guides/mysql/reconfigure/reconfigure-steps/yamls/reconfigure-using-secret.yaml
mysqlopsrequest.ops.kubedb.com/myops-reconfigure-config created
Verify the new configuration is working
If everything goes well, KubeDB Enterprise operator will update the configSecret of MySQL object.
Let’s wait for MySQLOpsRequest to be Successful. Run the following command to watch MySQLOpsRequest CR,
$ kubectl get mysqlopsrequest --all-namespaces
NAMESPACE NAME TYPE STATUS AGE
demo myops-reconfigure-config Reconfigure Successful 3m8s
We can see from the above output that the MySQLOpsRequest has succeeded. If we describe the MySQLOpsRequest we will get an overview of the steps that were followed to reconfigure the database.
$ kubectl describe mysqlopsrequest -n demo myops-reconfigure-config
Name: myops-reconfigure-config
Namespace: demo
Labels: <none>
Annotations: <none>
API Version: ops.kubedb.com/v1alpha1
Kind: MySQLOpsRequest
Metadata:
Creation Timestamp: 2022-11-23T09:09:20Z
Generation: 1
Managed Fields:
API Version: ops.kubedb.com/v1alpha1
Fields Type: FieldsV1
fieldsV1:
f:metadata:
f:annotations:
.:
f:kubectl.kubernetes.io/last-applied-configuration:
f:spec:
.:
f:apply:
f:configuration:
.:
f:configSecret:
f:databaseRef:
f:type:
Manager: kubectl-client-side-apply
Operation: Update
Time: 2022-11-23T09:09:20Z
API Version: ops.kubedb.com/v1alpha1
Fields Type: FieldsV1
fieldsV1:
f:status:
.:
f:conditions:
f:observedGeneration:
f:phase:
Manager: kubedb-ops-manager
Operation: Update
Subresource: status
Time: 2022-11-23T09:09:20Z
Resource Version: 786443
UID: 253ff2e3-0647-4926-bfb9-ef44b3b8a31d
Spec:
Apply: IfReady
Configuration:
Config Secret:
Name: new-my-configuration
Database Ref:
Name: sample-mysql
Type: Reconfigure
Status:
Conditions:
Last Transition Time: 2022-11-23T09:09:20Z
Message: Controller has started to Progress the MySQLOpsRequest: demo/myops-reconfigure-config
Observed Generation: 1
Reason: OpsRequestProgressingStarted
Status: True
Type: Progressing
Last Transition Time: 2022-11-23T09:13:10Z
Message: Successfully reconfigured MySQL pod for MySQLOpsRequest: demo/myops-reconfigure-config
Observed Generation: 1
Reason: SuccessfullyDBReconfigured
Status: True
Type: Reconfigure
Last Transition Time: 2022-11-23T09:13:10Z
Message: Controller has successfully reconfigure the MySQL demo/myops-reconfigure-config
Observed Generation: 1
Reason: OpsRequestProcessedSuccessfully
Status: True
Type: Successful
Observed Generation: 1
Phase: Successful
Events:
Type Reason Age From Message
---- ------ ---- ---- -------
Normal Starting 30m KubeDB Enterprise Operator Start processing for MySQLOpsRequest: demo/myops-reconfigure-config
Normal Starting 30m KubeDB Enterprise Operator Pausing MySQL databse: demo/sample-mysql
Normal Successful 30m KubeDB Enterprise Operator Successfully paused MySQL database: demo/sample-mysql for MySQLOpsRequest: myops-reconfigure-config
Normal Starting 30m KubeDB Enterprise Operator Restarting Pod: sample-mysql-1/demo
Normal Starting 29m KubeDB Enterprise Operator Restarting Pod: sample-mysql-2/demo
Normal Starting 28m KubeDB Enterprise Operator Restarting Pod: sample-mysql-0/demo
Normal Successful 27m KubeDB Enterprise Operator Successfully reconfigured MySQL pod for MySQLOpsRequest: demo/myops-reconfigure-config
Normal Starting 27m KubeDB Enterprise Operator Reconfiguring MySQL
Normal Successful 27m KubeDB Enterprise Operator Successfully reconfigure the MySQL object
Normal Starting 27m KubeDB Enterprise Operator Resuming MySQL database: demo/sample-mysql
Normal Successful 27m KubeDB Enterprise Operator Successfully resumed MySQL database: demo/sample-mysql
Normal Successful 27m KubeDB Enterprise Operator Controller has Successfully reconfigure the of MySQL: demo/sample-mysql
Now let’s connect to a mysql instance and run a mysql internal command to check the new configuration we have provided.
$ kubectl exec -it -n demo sample-mysql-0 -- bash
bash-4.4# mysql -u${MYSQL_ROOT_USERNAME} -p${MYSQL_ROOT_PASSWORD}
mysql: [Warning] Using a password on the command line interface can be insecure.
Welcome to the MySQL monitor. Commands end with ; or \g.
Your MySQL connection id is 279
Server version: 8.0.31 MySQL Community Server - GPL
Copyright (c) 2000, 2022, Oracle and/or its affiliates.
Oracle is a registered trademark of Oracle Corporation and/or its
affiliates. Other names may be trademarks of their respective
owners.
Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.
mysql>
mysql>
mysql> show variables like 'max_connections';
+-----------------+-------+
| Variable_name | Value |
+-----------------+-------+
| max_connections | 250 |
+-----------------+-------+
1 row in set (0.00 sec)
mysql> show variables like 'read_buffer_size';
+------------------+--------+
| Variable_name | Value |
+------------------+--------+
| read_buffer_size | 122880 |
+------------------+--------+
1 row in set (0.00 sec)
mysql>
As we can see from the configuration has changed, the value of max_connections has been changed from 200 to 250 and and the read_buffer_size has been changed 1048576 to 122880. So the reconfiguration of the database is successful.
Remove Custom Configuration
We can also remove exisiting custom config using MySQLOpsRequest. Provide true to field spec.configuration.removeCustomConfig and make an Ops Request to remove existing custom configuration.
Create MySQLOpsRequest
Lets create an MySQLOpsRequest having spec.configuration.removeCustomConfig is equal true,
apiVersion: ops.kubedb.com/v1alpha1
kind: MySQLOpsRequest
metadata:
name: myops-reconfigure-remove
namespace: demo
spec:
type: Reconfigure
databaseRef:
name: sample-mysql
configuration:
removeCustomConfig: true
Here,
spec.databaseRef.namespecifies that we are reconfiguringmyops-reconfigure-removedatabase.spec.typespecifies that we are performingReconfigureon our database.spec.configuration.removeCustomConfigis a bool field that should betruewhen you want to remove existing custom configuration.
Let’s create the MySQLOpsRequest CR we have shown above,
$ kubectl apply -f https://github.com/kubedb/docs/raw/v2023.11.2/docs/guides/mysql/reconfigure/yamls/reconfigure-steps/reconfigure-remove.yaml
mysqlopsrequest.ops.kubedb.com/mdops-reconfigure-remove created
Verify the new configuration is working
If everything goes well, KubeDB Enterprise operator will update the configSecret of MySQL object.
Let’s wait for MySQLOpsRequest to be Successful. Run the following command to watch MariaDBOpsRequest CR,
$ kubectl get mysqlopsrequest --all-namespaces
NAMESPACE NAME TYPE STATUS AGE
demo mdops-reconfigure-remove Reconfigure Successful 2m1s
Now let’s connect to a mysql instance and run a mysql internal command to check the new configuration we have provided.
$ kubectl exec -it -n demo sample-mysql-0 -- bash
bash-4.4# mysql -u${MYSQL_ROOT_USERNAME} -p${MYSQL_ROOT_PASSWORD}
mysql: [Warning] Using a password on the command line interface can be insecure.
Welcome to the MySQL monitor. Commands end with ; or \g.
Your MySQL connection id is 279
Server version: 8.0.31 MySQL Community Server - GPL
Copyright (c) 2000, 2022, Oracle and/or its affiliates.
Oracle is a registered trademark of Oracle Corporation and/or its
affiliates. Other names may be trademarks of their respective
owners.
Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.
mysql>
mysql>
mysql> show variables like 'max_connections';
+-----------------+-------+
| Variable_name | Value |
+-----------------+-------+
| max_connections | 151 |
+-----------------+-------+
1 row in set (0.00 sec)
mysql> show variables like 'read_buffer_size';
+------------------+--------+
| Variable_name | Value |
+------------------+--------+
| read_buffer_size | 131072 |
+------------------+--------+
1 row in set (0.00 sec)
mysql>
As we can see from the configuration has changed to its default value. So removal of existing custom configuration using MySQLOpsRequest is successful.
Cleaning Up
To clean up the Kubernetes resources created by this tutorial, run:
$ kubectl delete mysql -n demo sample-mysql
$ kubectl delete mysqlopsrequest -n demo myops-reconfigure-config mdops-reconfigure-remove
$ kubectl delete ns demo