New to KubeDB? Please start here.

ProxySQL Cluster

This guide will show you how to use KubeDB Enterprise operator to set up a ProxySQL 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:
- ProxySQL
- ProxySQL Cluster

To keep everything isolated, we are going to use a separate namespace called demo throughout this tutorial.

$ kubectl create ns demo
namespace/demo created

Prepare MySQL backend

We need a mysql backend for the proxysql server. So we are creating one with the below yaml.

apiVersion: kubedb.com/v1alpha2
kind: MySQL
metadata:
  name: mysql-server
  namespace: demo
spec:
  version: "5.7.44"
  replicas: 3
  topology:
    mode: GroupReplication
  storageType: Durable
  storage:
    storageClassName: "standard"
    accessModes:
      - ReadWriteOnce
    resources:
      requests:
        storage: 1Gi
  terminationPolicy: WipeOut

$ kubectl apply -f https://github.com/kubedb/docs/raw/v2024.6.4/docs/guides/proxysql/clustering/proxysql-cluster/examples/sample-mysql.yaml
mysql.kubedb.com/mysql-server created

Let’s wait for the MySQL to be Ready.

$ kubectl get mysql -n demo 
NAME           VERSION   STATUS   AGE
mysql-server   5.7.44    Ready    3m51s

Let’s first create an user in the backend mysql server and a database to test test the proxy traffic .

$ kubectl exec -it -n demo mysql-server-0 -- bash
Defaulted container "mysql" out of: mysql, mysql-coordinator, mysql-init (init)
root@mysql-server-0:/# 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 195
Server version: 5.7.44-log MySQL Community Server (GPL)

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> create user `test`@'%' identified by 'pass';
Query OK, 0 rows affected (0.00 sec)

mysql> create database test;
Query OK, 1 row affected (0.01 sec)

mysql> use test;
Database changed

mysql> show tables;
Empty set (0.00 sec)

mysql> create table testtb(name varchar(103), primary key(name));
Query OK, 0 rows affected (0.01 sec)

mysql> grant all privileges on test.* to 'test'@'%';
Query OK, 0 rows affected (0.00 sec)

mysql> flush privileges;
Query OK, 0 rows affected (0.00 sec)

mysql> exit
Bye

Deploy ProxySQL Cluster

The following is an example ProxySQL object which creates a proxysql cluster with three members.

apiVersion: kubedb.com/v1alpha2
kind: ProxySQL
metadata:
  name: proxy-server
  namespace: demo
spec:
  version: "2.3.2-debian"  
  replicas: 3
  backend:
    name: mysql-server
  terminationPolicy: WipeOut

To deploy a simple proxysql cluster all you need to do is just set the .spec.replicas field to a higher value than 2.

Let’s apply the yaml.

$ kubectl apply -f https://github.com/kubedb/docs/raw/v2024.6.4/docs/guides/proxysql/clustering/proxysql-cluster/examples/sample-proxysql.yaml
proxysql.kubedb.com/proxysql-server created

Let’s wait for the ProxySQL to be Ready.

$ kubectl get proxysql -n demo
NAME           VERSION        STATUS   AGE
proxy-server   2.3.2-debian   Ready    4m

Let’s see the pods

$ kubectl get pods -n demo | grep proxy
proxy-server-0   1/1     Running   3          4m
proxy-server-1   1/1     Running   3          4m
proxy-server-2   1/1     Running   3          4m

We can see that three nodes are up now.

Check proxysql_servers table

Let’s check the proxysql_servers table inside the ProxySQL pods.

#first node
$ kubectl exec -it -n demo proxy-server-0 -- bash 
root@proxy-server-0:/# mysql -uadmin -padmin -h127.0.0.1 -P6032 --prompt "ProxySQLAdmin > "
Welcome to the MariaDB monitor.  Commands end with ; or \g.
Your MySQL connection id is 316
Server version: 8.0.35 (ProxySQL Admin Module)

Copyright (c) 2000, 2018, Oracle, MariaDB Corporation Ab and others.

Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.

ProxySQLAdmin > select * from runtime_proxysql_servers;
+---------------------------------------+------+--------+---------+
| hostname                              | port | weight | comment |
+---------------------------------------+------+--------+---------+
| proxy-server-2.proxy-server-pods.demo | 6032 | 1      |         |
| proxy-server-1.proxy-server-pods.demo | 6032 | 1      |         |
| proxy-server-0.proxy-server-pods.demo | 6032 | 1      |         |
+---------------------------------------+------+--------+---------+
3 rows in set (0.000 sec)

ProxySQLAdmin > exit
Bye

#second node
$ kubectl exec -it -n demo proxy-server-1 -- bash 
root@proxy-server-0:/# mysql -uadmin -padmin -h127.0.0.1 -P6032 --prompt "ProxySQLAdmin >"
Welcome to the MariaDB monitor.  Commands end with ; or \g.
Your MySQL connection id is 316
Server version: 8.0.35 (ProxySQL Admin Module)

Copyright (c) 2000, 2018, Oracle, MariaDB Corporation Ab and others.

Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.

ProxySQLAdmin > select * from runtime_proxysql_servers;
+---------------------------------------+------+--------+---------+
| hostname                              | port | weight | comment |
+---------------------------------------+------+--------+---------+
| proxy-server-2.proxy-server-pods.demo | 6032 | 1      |         |
| proxy-server-1.proxy-server-pods.demo | 6032 | 1      |         |
| proxy-server-0.proxy-server-pods.demo | 6032 | 1      |         |
+---------------------------------------+------+--------+---------+
3 rows in set (0.000 sec)

ProxySQLAdmin >exit
Bye

#third node
$ kubectl exec -it -n demo proxy-server-2 -- bash 
root@proxy-server-0:/# mysql -uadmin -padmin -h127.0.0.1 -P6032 --prompt "ProxySQLAdmin >"
Welcome to the MariaDB monitor.  Commands end with ; or \g.
Your MySQL connection id is 316
Server version: 8.0.35 (ProxySQL Admin Module)

Copyright (c) 2000, 2018, Oracle, MariaDB Corporation Ab and others.

Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.

ProxySQLAdmin > select * from runtime_proxysql_servers;
+---------------------------------------+------+--------+---------+
| hostname                              | port | weight | comment |
+---------------------------------------+------+--------+---------+
| proxy-server-2.proxy-server-pods.demo | 6032 | 1      |         |
| proxy-server-1.proxy-server-pods.demo | 6032 | 1      |         |
| proxy-server-0.proxy-server-pods.demo | 6032 | 1      |         |
+---------------------------------------+------+--------+---------+
3 rows in set (0.000 sec)

ProxySQLAdmin >exit
Bye

From the above output we can see that the proxysql_servers tables has been successfuly set up.

Create test user in proxysql server

Let’s insert the test user inside the proxysql server

$ kubectl exec -it -n demo proxy-server-1 -- bash 
root@proxy-server-0:/# mysql -uadmin -padmin -h127.0.0.1 -P6032 --prompt "ProxySQLAdmin >"
Welcome to the MariaDB monitor.  Commands end with ; or \g.
Your MySQL connection id is 316
Server version: 8.0.35 (ProxySQL Admin Module)

Copyright (c) 2000, 2018, Oracle, MariaDB Corporation Ab and others.

Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.

ProxySQLAdmin > insert into mysql_users(username,password,default_hostgroup) values('test','pass',2);
Query OK, 1 row affected (0.001 sec)

ProxySQLAdmin > LOAD MYSQL USERS TO RUNTIME;
Query OK, 0 rows affected (0.000 sec)

ProxySQLAdmin > SAVE MYSQL USERS TO DISK;
Query OK, 0 rows affected (0.009 sec)

Check load balance

Now lets check the load balancing through the cluster.

First we need to create a script to sent load over the ProxySQL. We will use the test user and the test table to check and send the load.

$ kubectl exec -it -n demo proxy-server-1 -- bash
root@proxy-server-1:/# apt update
... ... ... 
root@proxy-server-1:/# apt install nano
... ... ... 
root@proxy-server-1:/# nano load.sh
# copy paste the load.sh file here
GNU nano 5.4                    load.sh                                                                      
#!/bin/bash

COUNTER=0

USER='test'
PROXYSQL_NAME='proxy-server'
NAMESPACE='demo'
PASS='pass'

VAR="x"

while [  $COUNTER -lt 100 ]; do
    let COUNTER=COUNTER+1
    VAR=a$VAR
    mysql -u$USER -h$PROXYSQL_NAME.$NAMESPACE.svc -P6033 -p$PASS -e 'select 1;' > /dev/null 2>&1
    mysql -u$USER -h$PROXYSQL_NAME.$NAMESPACE.svc -P6033 -p$PASS -e "INSERT INTO test.testtb(name) VALUES ('$VAR');" > /dev/null 2>&1
    mysql -u$USER -h$PROXYSQL_NAME.$NAMESPACE.svc -P6033 -p$PASS -e "select * from test.testtb;" > /dev/null 2>&1
    sleep 0.0001
done

root@proxy-server-1:/# chmod +x load.sh

root@proxy-server-1:/# ./load.sh

You can find the load.sh file here

$ kubectl exec -it -n demo proxy-server-1 -- bash 
root@proxy-server-0:/# mysql -uadmin -padmin -h127.0.0.1 -P6032 --prompt "ProxySQLAdmin >"
Welcome to the MariaDB monitor.  Commands end with ; or \g.
Your MySQL connection id is 316
Server version: 8.0.35 (ProxySQL Admin Module)

Copyright (c) 2000, 2018, Oracle, MariaDB Corporation Ab and others.

Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.

ProxySQLAdmin > select hostname, Queries from stats_proxysql_servers_metrics;
+---------------------------------------+---------+
| hostname                              | Queries |
+---------------------------------------+---------+
| proxy-server-2.proxy-server-pods.demo | 122     |
| proxy-server-1.proxy-server-pods.demo | 94      |
| proxy-server-0.proxy-server-pods.demo | 101     |
+---------------------------------------+---------+
3 rows in set (0.000 sec)

ProxySQLAdmin > select hostgroup,srv_host,Queries from stats_mysql_connection_pool;
+-----------+-------------------------------+---------+
| hostgroup | srv_host                      | Queries |
+-----------+-------------------------------+---------+
| 2         | mysql-server.demo.svc         | 30      |
| 3         | mysql-server-standby.demo.svc | 100     |
| 3         | mysql-server.demo.svc         | 34      |
+-----------+-------------------------------+---------+

From the above output we can see that the loads are properly distributed over the proxysql servers and the backend mysqls.

Chekc cluster sync

Let’s check if any configuration change is automatically propagated to other in out proxysql cluster.

We will change the admin-restapi_enabled in one cluster and observe the change in others.

First check the current status.

$ kubectl exec -it -n demo proxy-server-0 -- bash 
root@proxy-server-0:/# mysql -uadmin -padmin -h127.0.0.1 -P6032 -e "show variables like 'admin-restapi_enabled';"
+-----------------------+-------+
| Variable_name         | Value |
+-----------------------+-------+
| admin-restapi_enabled | false |
+-----------------------+-------+
root@proxy-server-0:/# exit
exit 

$ kubectl exec -it -n demo proxy-server-1 -- bash 
root@proxy-server-1:/# mysql -uadmin -padmin -h127.0.0.1 -P6032 -e "show variables like 'admin-restapi_enabled';"
+-----------------------+-------+
| Variable_name         | Value |
+-----------------------+-------+
| admin-restapi_enabled | false |
+-----------------------+-------+
root@proxy-server-1:/# exit
exit 

$ kubectl exec -it -n demo proxy-server-2 -- bash 
root@proxy-server-2:/# mysql -uadmin -padmin -h127.0.0.1 -P6032 -e "show variables like 'admin-restapi_enabled';"
+-----------------------+-------+
| Variable_name         | Value |
+-----------------------+-------+
| admin-restapi_enabled | false |
+-----------------------+-------+
root@proxy-server-2:/# exit
exit

Now set the value to true in server 0 .


$ kubectl exec -it -n demo proxy-server-0 -- bash
root@proxy-server-0:/# mysql -uadmin -padmin -h127.0.0.1 -P6032 -e "set admin-restapi_enabled='true';"
root@proxy-server-0:/# mysql -uadmin -padmin -h127.0.0.1 -P6032 -e "show variables like 'admin-restapi_enabled';"
+-----------------------+-------+
| Variable_name         | Value |
+-----------------------+-------+
| admin-restapi_enabled | true  |
+-----------------------+-------+
root@proxy-server-0:/# exit
exit 

$ kubectl exec -it -n demo proxy-server-1 -- bash
root@proxy-server-1:/# mysql -uadmin -padmin -h127.0.0.1 -P6032 -e "show variables like 'admin-restapi_enabled';"
+-----------------------+-------+
| Variable_name         | Value |
+-----------------------+-------+
| admin-restapi_enabled | true  |
+-----------------------+-------+
root@proxy-server-1:/# exit
exit 

$ kubectl exec -it -n demo proxy-server-2 -- bash
root@proxy-server-2:/# mysql -uadmin -padmin -h127.0.0.1 -P6032 -e "show variables like 'admin-restapi_enabled';"
+-----------------------+-------+
| Variable_name         | Value |
+-----------------------+-------+
| admin-restapi_enabled | true  |
+-----------------------+-------+
root@proxy-server-2:/# exit
exit

From the above output we can see that the cluster is always in sync and the configuration change is always propagated to other cluster nodes.

Cluster failover recovery

In case of any pod crash for proxysql cluster, the statefulset which was created by KubeDb operator creates another pod and the is auto joins the cluster. We can delete a pod and wait for that to create again and join the cluster and test this feature.

Let’s see the current status first.

ProxySQLAdmin > SELECT hostname, checksum, FROM_UNIXTIME(changed_at) changed_at, FROM_UNIXTIME(updated_at) updated_at FROM stats_proxysql_servers_checksums WHERE name='mysql_users' ORDER BY hostname;
+---------------------------------------+--------------------+---------------------+---------------------+
| hostname                              | checksum           | changed_at          | updated_at          |
+---------------------------------------+--------------------+---------------------+---------------------+
| proxy-server-0.proxy-server-pods.demo | 0x49728B20D3BC91AC | 2022-11-15 06:09:49 | 2022-11-15 06:34:28 |
| proxy-server-1.proxy-server-pods.demo | 0x49728B20D3BC91AC | 2022-11-15 06:10:22 | 2022-11-15 06:34:28 |
| proxy-server-2.proxy-server-pods.demo | 0x49728B20D3BC91AC | 2022-11-15 06:10:17 | 2022-11-15 06:34:28 |
+---------------------------------------+--------------------+---------------------+---------------------+
3 rows in set (0.000 sec)

Now let’s delete the pod-2.

$ kubectl delete pod -n demo proxy-server-2
pod "proxy-server-2" deleted

Let’s watch the cluster status now.

ProxySQLAdmin > SELECT hostname, checksum, FROM_UNIXTIME(changed_at) changed_at, FROM_UNIXTIME(updated_at) updated_at FROM stats_proxysql_servers_checksums WHERE name='mysql_users' ORDER BY hostname;
+---------------------------------------+--------------------+---------------------+---------------------+
| hostname                              | checksum           | changed_at          | updated_at          |
+---------------------------------------+--------------------+---------------------+---------------------+
| proxy-server-0.proxy-server-pods.demo | 0x49728B20D3BC91AC | 2022-11-15 06:09:49 | 2022-11-15 06:34:28 |
| proxy-server-1.proxy-server-pods.demo | 0x49728B20D3BC91AC | 2022-11-15 06:10:22 | 2022-11-15 06:34:28 |
| proxy-server-2.proxy-server-pods.demo | 0x49728B20D3BC91AC | 2022-11-15 06:10:17 | 2022-11-15 06:34:28 |
+---------------------------------------+--------------------+---------------------+---------------------+
3 rows in set (0.000 sec)
ProxySQLAdmin > SELECT hostname, checksum, FROM_UNIXTIME(changed_at) changed_at, FROM_UNIXTIME(updated_at) updated_at FROM stats_proxysql_servers_checksums WHERE name='mysql_users' ORDER BY hostname;
+---------------------------------------+--------------------+---------------------+---------------------+
| hostname                              | checksum           | changed_at          | updated_at          |
+---------------------------------------+--------------------+---------------------+---------------------+
| proxy-server-0.proxy-server-pods.demo | 0x49728B20D3BC91AC | 2022-11-15 06:09:49 | 2022-11-15 06:34:28 |
| proxy-server-1.proxy-server-pods.demo | 0x49728B20D3BC91AC | 2022-11-15 06:10:22 | 2022-11-15 06:34:28 |
| proxy-server-2.proxy-server-pods.demo | 0x49728B20D3BC91AC | 2022-11-15 06:10:17 | 2022-11-15 06:34:28 |
+---------------------------------------+--------------------+---------------------+---------------------+
3 rows in set (0.000 sec)

... ... ...

ProxySQLAdmin > SELECT hostname, checksum, FROM_UNIXTIME(changed_at) changed_at, FROM_UNIXTIME(updated_at) updated_at FROM stats_proxysql_servers_checksums WHERE name='mysql_users' ORDER BY hostname;
+---------------------------------------+--------------------+---------------------+---------------------+
| hostname                              | checksum           | changed_at          | updated_at          |
+---------------------------------------+--------------------+---------------------+---------------------+
| proxy-server-0.proxy-server-pods.demo | 0x49728B20D3BC91AC | 2022-11-15 06:09:49 | 2022-11-15 06:34:40 |
| proxy-server-1.proxy-server-pods.demo | 0x49728B20D3BC91AC | 2022-11-15 06:10:22 | 2022-11-15 06:34:40 |
| proxy-server-2.proxy-server-pods.demo | 0x49728B20D3BC91AC | 2022-11-15 06:10:17 | 2022-11-15 06:34:28 |
+---------------------------------------+--------------------+---------------------+---------------------+
3 rows in set (0.000 sec)

... ... ...

ProxySQLAdmin > SELECT hostname, checksum, FROM_UNIXTIME(changed_at) changed_at, FROM_UNIXTIME(updated_at) updated_at FROM stats_proxysql_servers_checksums WHERE name='mysql_users' ORDER BY hostname;
+---------------------------------------+--------------------+---------------------+---------------------+
| hostname                              | checksum           | changed_at          | updated_at          |
+---------------------------------------+--------------------+---------------------+---------------------+
| proxy-server-0.proxy-server-pods.demo | 0x49728B20D3BC91AC | 2022-11-15 06:09:49 | 2022-11-15 06:34:40 |
| proxy-server-1.proxy-server-pods.demo | 0x49728B20D3BC91AC | 2022-11-15 06:10:22 | 2022-11-15 06:34:40 |
| proxy-server-2.proxy-server-pods.demo | 0x49728B20D3BC91AC | 2022-11-15 06:10:17 | 2022-11-15 06:34:28 |
+---------------------------------------+--------------------+---------------------+---------------------+
3 rows in set (0.000 sec)

From the above output we can see that the third server is out of sync as it is not available right now. But the other two are in sync.

Wait for the new pod come up.

$ kubectl get pod -n demo proxy-server-2
NAME             READY   STATUS    RESTARTS   AGE
proxy-server-2   1/1     Running   0          94s

Now check the status again.

ProxySQLAdmin > SELECT hostname, checksum, FROM_UNIXTIME(changed_at) changed_at, FROM_UNIXTIME(updated_at) updated_at FROM stats_proxysql_servers_checksums WHERE name='mysql_users' ORDER BY hostname;
+---------------------------------------+--------------------+---------------------+---------------------+
| hostname                              | checksum           | changed_at          | updated_at          |
+---------------------------------------+--------------------+---------------------+---------------------+
| proxy-server-0.proxy-server-pods.demo | 0x49728B20D3BC91AC | 2022-11-15 06:09:49 | 2022-11-15 06:34:50 |
| proxy-server-1.proxy-server-pods.demo | 0x49728B20D3BC91AC | 2022-11-15 06:10:22 | 2022-11-15 06:34:50 |
| proxy-server-2.proxy-server-pods.demo | 0x49728B20D3BC91AC | 2022-11-15 06:10:17 | 2022-11-15 06:34:28 |
+---------------------------------------+--------------------+---------------------+---------------------+
3 rows in set (0.000 sec)

... ... ...

ProxySQLAdmin > SELECT hostname, checksum, FROM_UNIXTIME(changed_at) changed_at, FROM_UNIXTIME(updated_at) updated_at FROM stats_proxysql_servers_checksums WHERE name='mysql_users' ORDER BY hostname;
+---------------------------------------+--------------------+---------------------+---------------------+
| hostname                              | checksum           | changed_at          | updated_at          |
+---------------------------------------+--------------------+---------------------+---------------------+
| proxy-server-0.proxy-server-pods.demo | 0x49728B20D3BC91AC | 2022-11-15 06:09:49 | 2022-11-15 06:35:15 |
| proxy-server-1.proxy-server-pods.demo | 0x49728B20D3BC91AC | 2022-11-15 06:10:22 | 2022-11-15 06:35:15 |
| proxy-server-2.proxy-server-pods.demo | 0x49728B20D3BC91AC | 2022-11-15 06:10:17 | 2022-11-15 06:35:15 |
+---------------------------------------+--------------------+---------------------+---------------------+
3 rows in set (0.000 sec)

From the above output we can see that the new pod is now in sync with the two others. So the failover recovery is successful.

Cleaning up

$ kubectl delete proxysql -n demo proxy-server
proxysql.kubedb.com "proxy-server" deleted
$ kubectl delete mysql -n demo mysql-server
mysql.kubedb.com "mysql-server" deleted

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