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Reconfigure PerconaXtraDB Cluster Database

This guide will show you how to use KubeDB Enterprise operator to reconfigure a PerconaXtraDB Cluster.

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.
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

Now, we are going to deploy a PerconaXtraDB Cluster using a supported version by KubeDB operator. Then we are going to apply PerconaXtraDBOpsRequest to reconfigure its configuration.

Prepare PerconaXtraDB Cluster

Now, we are going to deploy a PerconaXtraDB Cluster database with version 10.6.16.

Deploy PerconaXtraDB

At first, we will create px-config.cnf file containing required configuration settings.

$ cat px-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 px-configuration --from-file=./px-config.cnf
secret/px-configuration created

In this section, we are going to create a PerconaXtraDB object specifying spec.configSecret field to apply this custom configuration. 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
  configSecret:
    name: px-configuration
  storageType: Durable
  storage:
    storageClassName: "standard"
    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/v2024.1.26-rc.0/docs/guides/percona-xtradb/reconfigure/cluster/examples/sample-pxc-config.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    71s

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 perconaxtradb instance,

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

$ kubectl get secrets -n demo sample-pxc-auth -o jsonpath='{.data.\password}' | base64 -d                                                                         
nrKuxni0wDSMrgwy

Now, we will check if the database has started with the custom configuration we have provided.

$ kubectl exec -it -n demo sample-pxc-0 -- bash
Defaulted container "perconaxtradb" out of: perconaxtradb, px-coordinator, px-init (init)
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 3699
Server version: 8.0.26-16.1 Percona XtraDB Cluster (GPL), Release rel16, Revision b141904, WSREP version 26.4.3

Copyright (c) 2009-2021 Percona LLC and/or its affiliates
Copyright (c) 2000, 2021, 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)


# value of `read_buffer_size` is same as provided 
mysql> show variables like 'read_buffer_size';
+------------------+--------+
| Variable_name    | Value  |
+------------------+--------+
| read_buffer_size | 1048576 |
+------------------+--------+
1 row in set (0.00 sec)


mysql> exit
Bye

As we can see from the configuration of ready perconaxtradb, 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-px-config.cnf containing required configuration settings.

$ cat new-px-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-px-configuration --from-file=./new-px-config.cnf
secret/new-px-configuration created

Create PerconaXtraDBOpsRequest

Now, we will use this secret to replace the previous secret using a PerconaXtraDBOpsRequest CR. The PerconaXtraDBOpsRequest yaml is given below,

apiVersion: ops.kubedb.com/v1alpha1
kind: PerconaXtraDBOpsRequest
metadata:
  name: pxops-reconfigure-config
  namespace: demo
spec:
  type: Reconfigure
  databaseRef:
    name: sample-pxc
  configuration:   
    configSecret:
      name: new-px-configuration

Here,

spec.databaseRef.name specifies that we are reconfiguring sample-pxc database.
spec.type specifies that we are performing Reconfigure on our database.
spec.configuration.configSecret.name specifies the name of the new secret.

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

$ kubectl apply -f https://github.com/kubedb/docs/raw/v2024.1.26-rc.0/docs/guides/percona-xtradb/reconfigure/cluster/examples/reconfigure-using-secret.yaml
perconaxtradbopsrequest.ops.kubedb.com/pxops-reconfigure-config created

Verify the new configuration is working

If everything goes well, KubeDB Enterprise operator will update the configSecret of PerconaXtraDB object.

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

$ kubectl get perconaxtradbopsrequest --all-namespaces
NAMESPACE   NAME                       TYPE          STATUS       AGE
demo        pxops-reconfigure-config   Reconfigure   Successful   3m8s

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 reconfigure the database.

$ kubectl describe perconaxtradbopsrequest -n demo pxops-reconfigure-config
Name:         pxops-reconfigure-config
Namespace:    demo
Labels:       <none>
Annotations:  <none>
API Version:  ops.kubedb.com/v1alpha1
Kind:         PerconaXtraDBOpsRequest
Metadata:
  Creation Timestamp:  2022-06-10T04:43:50Z
  Generation:          1
  Resource Version:  1123451
  UID:               27a73fc6-1d25-4019-8975-f7d4daf782b7
Spec:
  Configuration:
    Config Secret:
      Name:  new-px-configuration
  Database Ref:
    Name:  sample-pxc
  Type:    Reconfigure
Status:
  Conditions:
    Last Transition Time:  2022-06-10T04:43:50Z
    Message:               Controller has started to Progress the PerconaXtraDBOpsRequest: demo/pxops-reconfigure-config
    Observed Generation:   1
    Reason:                OpsRequestProgressingStarted
    Status:                True
    Type:                  Progressing
    Last Transition Time:  2022-06-10T04:47:25Z
    Message:               Successfully restarted PerconaXtraDB pods for PerconaXtraDBOpsRequest: demo/pxops-reconfigure-config
    Observed Generation:   1
    Reason:                SuccessfullyRestatedStatefulSet
    Status:                True
    Type:                  RestartStatefulSetPods
    Last Transition Time:  2022-06-10T04:47:30Z
    Message:               Successfully reconfigured PerconaXtraDB for PerconaXtraDBOpsRequest: demo/pxops-reconfigure-config
    Observed Generation:   1
    Reason:                SuccessfullyDBReconfigured
    Status:                True
    Type:                  DBReady
    Last Transition Time:  2022-06-10T04:47:30Z
    Message:               Controller has successfully reconfigure the PerconaXtraDB demo/pxops-reconfigure-config
    Observed Generation:   1
    Reason:                OpsRequestProcessedSuccessfully
    Status:                True
    Type:                  Successful
  Observed Generation:     3
  Phase:                   Successful

Now let’s connect to a perconaxtradb instance and run a perconaxtradb internal command to check the new configuration we have provided.

$ kubectl exec -it -n demo sample-pxc-0 -- bash
Defaulted container "perconaxtradb" out of: perconaxtradb, px-coordinator, px-init (init)
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 3699
Server version: 8.0.26-16.1 Percona XtraDB Cluster (GPL), Release rel16, Revision b141904, WSREP version 26.4.3

Copyright (c) 2009-2021 Percona LLC and/or its affiliates
Copyright (c) 2000, 2021, 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 | 250   |
+-----------------+-------+
1 row in set (0.00 sec)


# value of `read_buffer_size` is same as provided 
mysql> show variables like 'read_buffer_size';
+------------------+--------+
| Variable_name    | Value  |
+------------------+--------+
| read_buffer_size | 122880 |
+------------------+--------+
1 row in set (0.00 sec)


mysql> exit
Bye

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.

Reconfigure Existing Config Secret

Now, we will create a new PerconaXtraDBOpsRequest to reconfigure our existing secret new-px-configuration by modifying our new-px-config.cnf file using applyConfig. The PerconaXtraDBOpsRequest yaml is given below,

apiVersion: ops.kubedb.com/v1alpha1
kind: PerconaXtraDBOpsRequest
metadata:
  name: pxops-reconfigure-apply-config
  namespace: demo
spec:
  type: Reconfigure
  databaseRef:
    name: sample-pxc
  configuration:   
    applyConfig:
      new-px-config.cnf: |
        [mysqld]
        max_connections = 230
        read_buffer_size = 1064960        
      innodb-config.cnf: |
        [mysqld]
        innodb_log_buffer_size = 17408000

Note: You can modify multiple fields of your current configuration using applyConfig. If you don’t have any secrets then applyConfig will create a secret for you. Here, we modified value of our two existing fields which are max_connections and read_buffer_size also, we modified a new field innodb_log_buffer_size of our configuration.

Here,

spec.databaseRef.name specifies that we are reconfiguring sample-pxc database.
spec.type specifies that we are performing Reconfigure on our database.
spec.configuration.applyConfig contains the configuration of existing or newly created secret.

Before applying this yaml we are going to check the existing value of our new field,

$ kubectl exec -it -n demo sample-pxc-0 -- bash
Defaulted container "perconaxtradb" out of: perconaxtradb, px-coordinator, px-init (init)
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 3699
Server version: 8.0.26-16.1 Percona XtraDB Cluster (GPL), Release rel16, Revision b141904, WSREP version 26.4.3

Copyright (c) 2009-2021 Percona LLC and/or its affiliates
Copyright (c) 2000, 2021, 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 'innodb_log_buffer_size';
+------------------------+----------+
| Variable_name          | Value    |
+------------------------+----------+
| innodb_log_buffer_size | 16777216 |
+------------------------+----------+
1 row in set (0.00 sec)

PerconaXtraDB [(none)]> exit
Bye

16777216

Here, we can see the default value for innodb_log_buffer_size is 16777216.

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

$ kubectl apply -f https://github.com/kubedb/docs/raw/v2024.1.26-rc.0/docs/guides/percona-xtradb/reconfigure/cluster/examples/pxops-reconfigure-apply-config.yaml
perconaxtradbopsrequest.ops.kubedb.com/pxops-reconfigure-apply-config created

Verify the new configuration is working

If everything goes well, KubeDB Enterprise operator will update the configSecret of PerconaXtraDB object.

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

$ kubectl get perconaxtradbopsrequest pxops-reconfigure-apply-config -n demo
NAME                             TYPE          STATUS       AGE
pxops-reconfigure-apply-config   Reconfigure   Successful   4m59s

$ kubectl describe perconaxtradbopsrequest -n demo pxops-reconfigure-apply-config
Name:         pxops-reconfigure-apply-config
Namespace:    demo
Labels:       <none>
Annotations:  <none>
API Version:  ops.kubedb.com/v1alpha1
Kind:         PerconaXtraDBOpsRequest
Metadata:
  Creation Timestamp:  2022-06-10T09:13:49Z
  Generation:          1
  Resource Version:  14120
  UID:               eb8d5df5-a0ce-4011-890c-c18c0200b5ac
Spec:
  Configuration:
    Apply Config:
      innodb-config.cnf:  [mysqld]
innodb_log_buffer_size = 17408000

      new-px-config.cnf:  [mysqld]
max_connections = 230
read_buffer_size = 1064960

  Database Ref:
    Name:  sample-pxc
  Type:    Reconfigure
Status:
  Conditions:
    Last Transition Time:  2022-06-10T09:13:49Z
    Message:               Controller has started to Progress the PerconaXtraDBOpsRequest: demo/pxops-reconfigure-apply-config
    Observed Generation:   1
    Reason:                OpsRequestProgressingStarted
    Status:                True
    Type:                  Progressing
    Last Transition Time:  2022-06-10T09:13:49Z
    Message:               Successfully prepared user provided custom config secret
    Observed Generation:   1
    Reason:                PrepareSecureCustomConfig
    Status:                True
    Type:                  PrepareCustomConfig
    Last Transition Time:  2022-06-10T09:17:24Z
    Message:               Successfully restarted PerconaXtraDB pods for PerconaXtraDBOpsRequest: demo/pxops-reconfigure-apply-config
    Observed Generation:   1
    Reason:                SuccessfullyRestatedStatefulSet
    Status:                True
    Type:                  RestartStatefulSetPods
    Last Transition Time:  2022-06-10T09:17:29Z
    Message:               Successfully reconfigured PerconaXtraDB for PerconaXtraDBOpsRequest: demo/pxops-reconfigure-apply-config
    Observed Generation:   1
    Reason:                SuccessfullyDBReconfigured
    Status:                True
    Type:                  DBReady
    Last Transition Time:  2022-06-10T09:17:29Z
    Message:               Controller has successfully reconfigure the PerconaXtraDB demo/pxops-reconfigure-apply-config
    Observed Generation:   1
    Reason:                OpsRequestProcessedSuccessfully
    Status:                True
    Type:                  Successful
  Observed Generation:     3
  Phase:                   Successful

Now let’s connect to a perconaxtradb instance and run a perconaxtradb internal command to check the new configuration we have provided.

$ kubectl exec -it -n demo sample-pxc-0 -- bash
Defaulted container "perconaxtradb" out of: perconaxtradb, px-coordinator, px-init (init)
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 3699
Server version: 8.0.26-16.1 Percona XtraDB Cluster (GPL), Release rel16, Revision b141904, WSREP version 26.4.3

Copyright (c) 2009-2021 Percona LLC and/or its affiliates
Copyright (c) 2000, 2021, 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.
# value of `max_conncetions` is same as provided 
mysql> show variables like 'max_connections';
+-----------------+-------+
| Variable_name   | Value |
+-----------------+-------+
| max_connections | 230   |
+-----------------+-------+
1 row in set (0.001 sec)

# value of `read_buffer_size` is same as provided
mysql> show variables like 'read_buffer_size';
+------------------+---------+
| Variable_name    | Value   |
+------------------+---------+
| read_buffer_size | 1064960 |
+------------------+---------+
1 row in set (0.001 sec)

# value of `innodb_log_buffer_size` is same as provided
mysql> show variables like 'innodb_log_buffer_size';
+------------------------+----------+
| Variable_name          | Value    |
+------------------------+----------+
| innodb_log_buffer_size | 17408000 |
+------------------------+----------+
1 row in set (0.001 sec)

mysql> exit
Bye

As we can see from above the configuration has been changed, the value of max_connections has been changed from 250 to 230 and the read_buffer_size has been changed 122880 to 1064960 also, innodb_log_buffer_size has been changed from 16777216 to 17408000. So the reconfiguration of the sample-pxc database is successful.

Remove Custom Configuration

We can also remove existing custom config using PerconaXtraDBOpsRequest. Provide true to field spec.configuration.removeCustomConfig and make an Ops Request to remove existing custom configuration.

Create PerconaXtraDBOpsRequest

Lets create an PerconaXtraDBOpsRequest having spec.configuration.removeCustomConfig is equal true,

apiVersion: ops.kubedb.com/v1alpha1
kind: PerconaXtraDBOpsRequest
metadata:
  name: pxops-reconfigure-remove
  namespace: demo
spec:
  type: Reconfigure
  databaseRef:
    name: sample-pxc
  configuration:   
    removeCustomConfig: true

Here,

spec.databaseRef.name specifies that we are reconfiguring pxops-reconfigure-remove database.
spec.type specifies that we are performing Reconfigure on our database.
spec.configuration.removeCustomConfig is a bool field that should be true when you want to remove existing custom configuration.

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

$ kubectl apply -f https://github.com/kubedb/docs/raw/v2024.1.26-rc.0/docs/guides/percona-xtradb/reconfigure/cluster/examples/reconfigure-remove.yaml
perconaxtradbopsrequest.ops.kubedb.com/pxops-reconfigure-remove created

Verify the new configuration is working

If everything goes well, KubeDB Enterprise operator will update the configSecret of PerconaXtraDB object.

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

$ kubectl get perconaxtradbopsrequest --all-namespaces
NAMESPACE   NAME                       TYPE          STATUS       AGE
demo        pxops-reconfigure-remove   Reconfigure   Successful   2m1s

Now let’s connect to a perconaxtradb instance and run a perconaxtradb internal command to check the new configuration we have provided.

$ kubectl exec -it -n demo sample-pxc-0 -- bash
Defaulted container "perconaxtradb" out of: perconaxtradb, px-coordinator, px-init (init)
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 3699
Server version: 8.0.26-16.1 Percona XtraDB Cluster (GPL), Release rel16, Revision b141904, WSREP version 26.4.3

Copyright (c) 2009-2021 Percona LLC and/or its affiliates
Copyright (c) 2000, 2021, 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.

# value of `max_connections` is default
PerconaXtraDB [(none)]> show variables like 'max_connections';
+-----------------+-------+
| Variable_name   | Value |
+-----------------+-------+
| max_connections | 151   |
+-----------------+-------+
1 row in set (0.001 sec)

# value of `read_buffer_size` is default
PerconaXtraDB [(none)]> show variables like 'read_buffer_size';
+------------------+---------+
| Variable_name    | Value   |
+------------------+---------+
| read_buffer_size | 131072  |
+------------------+---------+
1 row in set (0.001 sec)

# value of `innodb_log_buffer_size` is default
PerconaXtraDB [(none)]> show variables like 'innodb_log_buffer_size';
+------------------------+----------+
| Variable_name          | Value    |
+------------------------+----------+
| innodb_log_buffer_size | 16777216 |
+------------------------+----------+
1 row in set (0.001 sec)

PerconaXtraDB [(none)]> exit
Bye

As we can see from the configuration has changed to its default value. So removal of existing custom configuration using PerconaXtraDBOpsRequest is successful.

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 pxops-reconfigure-config pxops-reconfigure-apply-config pxops-reconfigure-remove
$ kubectl delete ns demo

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Reconfigure PerconaXtraDB Cluster Database

Before You Begin

Prepare PerconaXtraDB Cluster

Deploy PerconaXtraDB

Reconfigure using new config secret

Create PerconaXtraDBOpsRequest

Verify the new configuration is working

Reconfigure Existing Config Secret

Verify the new configuration is working

Remove Custom Configuration

Create PerconaXtraDBOpsRequest

Verify the new configuration is working

Cleaning Up

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