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Using Custom Configuration File

KubeDB supports providing custom bootstrap configuration for ProxySQL. This tutorial will show you how to use KubeDB to run a ProxySQL server with custom configuration.

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.

• Now, install KubeDB cli on your workstation and KubeDB operator in your cluster following the steps here.

• To keep things isolated, this tutorial uses 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 here folder in GitHub repository kubedb/docs.

Overview

ProxySQL bootstraps itself from a proxysql.cnf configuration file built from a few tables: mysql_users, mysql_query_rules, mysql_variables and admin_variables. KubeDB lets you provide this bootstrap configuration declaratively through spec.configuration.init.secretName. You create a Secret containing one or more of the keys AdminVariables.cnf, MySQLVariables.cnf, MySQLUsers.cnf, MySQLQueryRules.cnf, and the operator patches their contents verbatim into proxysql.cnf during bootstrap. This configuration is applied only once, when ProxySQL is initialized.

Note: spec.configuration.init.inline lets you provide the same kind of bootstrap configuration as structured YAML instead of raw *.cnf text, and always takes precedence over secretName. See the ProxySQL concept page for details.

In this tutorial, we will set mysql-max_connections via a custom config file.

Prepare MySQL Backend

ProxySQL needs a backend server to proxy. We will use a 3 node MySQL Group Replication cluster set up with KubeDB.

apiVersion: kubedb.com/v1
kind: MySQL
metadata:
  name: mysql-server
  namespace: demo
spec:
  version: "8.4.3"
  replicas: 3
  topology:
    mode: GroupReplication
  storageType: Durable
  storage:
    storageClassName: "standard"
    accessModes:
      - ReadWriteOnce
    resources:
      requests:
        storage: 1Gi
  deletionPolicy: WipeOut

$ kubectl apply -f https://github.com/kubedb/docs/raw/v2026.4.27/docs/guides/proxysql/backends/mysqlgrp/examples/sample-mysql.yaml
mysql.kubedb.com/mysql-server created

Wait for the MySQL cluster to be Ready.

$ kubectl get my -n demo
NAME           VERSION   STATUS   AGE
mysql-server   8.4.3     Ready    7m6s

You can use MariaDB or Percona XtraDB as a backend as well. Have a look at the other ProxySQL backend examples.

Custom Configuration

At first, let’s create a MySQLVariables.cnf file setting mysql-max_connections.

$ cat MySQLVariables.cnf
mysql_variables=
{
    max_connections=2048
}

Now, create a Secret with this configuration file.

$ kubectl create secret generic -n demo proxysql-configuration --from-file=./MySQLVariables.cnf
secret/proxysql-configuration created

Now, create the ProxySQL crd specifying spec.configuration.init.secretName field.

$ kubectl apply -f https://github.com/kubedb/docs/raw/v2026.4.27/docs/guides/proxysql/configuration/using-config-file/examples/proxysql-custom.yaml
proxysql.kubedb.com/sample-proxysql created

Below is the YAML for the ProxySQL crd we just created.

apiVersion: kubedb.com/v1
kind: ProxySQL
metadata:
  name: sample-proxysql
  namespace: demo
spec:
  version: "2.7.3-debian"
  replicas: 1
  backend:
    name: mysql-server
  configuration:
    init:
      secretName: proxysql-configuration
  deletionPolicy: WipeOut

Now, wait a few minutes. KubeDB operator will create necessary petset, services, secret etc. If everything goes well, we will see that a pod with the name sample-proxysql-0 has been created.

Check that the petset’s pod is running

$ kubectl get pod -n demo
NAME                READY   STATUS    RESTARTS   AGE
sample-proxysql-0   1/1     Running   0          45s

$ kubectl get proxysql -n demo
NAME              VERSION        STATUS   AGE
sample-proxysql   2.7.3-debian   Ready    71s

We can see the ProxySQL is in Ready phase. Now, we will check if ProxySQL has bootstrapped with the custom configuration we have provided.

$ kubectl exec -it -n demo sample-proxysql-0 -- bash
root@sample-proxysql-0:/# mysql -uadmin -padmin -h127.0.0.1 -P6032 --prompt "ProxySQLAdmin > "
ProxySQLAdmin > select * from global_variables where variable_name='mysql-max_connections';
+------------------------+----------------+
| variable_name          | variable_value |
+------------------------+----------------+
| mysql-max_connections  | 2048           |
+------------------------+----------------+
1 row in set (0.00 sec)

ProxySQLAdmin > exit
Bye
root@sample-proxysql-0:/# exit
exit

We can see that the value of mysql-max_connections is the same as we provided in the custom config file.

Cleaning up

To cleanup the Kubernetes resources created by this tutorial, run:

$ kubectl delete proxysql -n demo sample-proxysql
proxysql.kubedb.com "sample-proxysql" deleted
$ kubectl delete mysql -n demo mysql-server
mysql.kubedb.com "mysql-server" deleted
$ kubectl delete ns demo
namespace "demo" deleted