Load balancing with ProxySQL For Percona XtraDB Cluster

Mughees Ahmed December 19, 2019 Leave a comment

We should consider installing ProxySQL on client nodes for efficient workload management across the cluster without any changes to the applications that generate queries. This is the recommended high-availability solution for Percona XtraDB Cluster.
Some of the popular features of ProxySQL are:

High performance
Efficient workload management
Query caching
Query routing
Supports failover
Advanced configuration with 0 downtime
Application layer proxy
Cross-platform
Advanced topology support
Firewall

Environment Specification:

192.168.56.115
centos

Pre requisites:

We need to open below ports on all server

firewall-cmd --zone=public --add-service=mysql --permanent

firewall-cmd --zone=public --add-port=3306/tcp --permanent
firewall-cmd --zone=public --add-port=4567/tcp --permanent
firewall-cmd --zone=public --add-port=4568/tcp --permanent
firewall-cmd --zone=public --add-port=4444/tcp --permanent
firewall-cmd --zone=public --add-port=4567/udp --permanent

Allow ProxySQL service port 6033/tcp (it is the reverse of MySQL default port 3306) in Linux Firewall.

firewall-cmd --permanent --add-port=6033/tcp

firewall-cmd --reload

Installing ProxySQL Load Balancer for Percona XtraDB Cluster on CentOS 7

ProxySQL v2 natively supports Percona XtraDB Cluster, To install ProxySql install it from the percona repository

sudo yum install proxysql2

To connect to the ProxySQL admin interface, you need a MySQL client.

yum install Percona-XtraDB-Cluster-client-57

Now start the proxysql service

[root@localhost ~]# systemctl start proxysql.service

To check port on cluster node use the below query.

mysql -uroot -p -e "SHOW GLOBAL VARIABLES LIKE 'PORT'";

Now connect to ProxySQL admin panel and configure the load balancer.

mysql -u admin -p123 -h 127.0.0.1 -P6032 --prompt='ProxySQL> '

INSERT INTO mysql_servers(hostgroup_id, hostname, port) VALUES (0,'192.168.56.110',3306);
INSERT INTO mysql_servers(hostgroup_id, hostname, port) VALUES (0,'192.168.56.113',3306);
INSERT INTO mysql_servers(hostgroup_id, hostname, port) VALUES (0,'192.168.56.114',3306);

ProxySQL> SELECT * FROM mysql_servers;
+--------------+----------------+------+-----------+--------+--------+-------------+-----------------+---------------------+---------+----------------+---------+
| hostgroup_id | hostname | port | gtid_port | status | weight | compression | max_connections | max_replication_lag | use_ssl | max_latency_ms | comment |
+--------------+----------------+------+-----------+--------+--------+-------------+-----------------+---------------------+---------+----------------+---------+
| 0 | 192.168.56.110 | 3306 | 0 | ONLINE | 1 | 0 | 1000 | 0 | 0 | 0 | |
| 0 | 192.168.56.113 | 3306 | 0 | ONLINE | 1 | 0 | 1000 | 0 | 0 | 0 | |
| 0 | 192.168.56.114 | 3306 | 0 | ONLINE | 1 | 0 | 1000 | 0 | 0 | 0 | |
+--------------+----------------+------+-----------+--------+--------+-------------+-----------------+---------------------+---------+----------------+---------+
3 rows in set (0.00 sec)

Configure ProxySQL Nodes Monitoring:

on any percona NODE:

CREATE USER 'proxysql'@'%' IDENTIFIED BY 'ProxySQL';
GRANT USAGE ON *.* TO 'proxysql'@'%';

mysql> CREATE USER 'proxysql'@'%' IDENTIFIED BY 'ProxySQL';
Query OK, 0 rows affected (0.01 sec)

mysql> GRANT USAGE ON *.* TO 'proxysql'@'%';
Query OK, 0 rows affected (0.02 sec)

UPDATE global_variables SET variable_value='proxysql' WHERE variable_name='mysql-monitor_username';

UPDATE global_variables SET variable_value='ProxySQL' WHERE variable_name='mysql-monitor_password';

LOAD MYSQL VARIABLES TO RUNTIME;

SAVE MYSQL VARIABLES TO DISK;

ProxySQL> UPDATE global_variables SET variable_value='proxysql' WHERE variable_name='mysql-monitor_username';
Query OK, 1 row affected (0.01 sec)

ProxySQL> UPDATE global_variables SET variable_value='ProxySQL' WHERE variable_name='mysql-monitor_password';
Query OK, 1 row affected (0.00 sec)

ProxySQL> LOAD MYSQL VARIABLES TO RUNTIME;
Query OK, 0 rows affected (0.00 sec)

ProxySQL> SAVE MYSQL VARIABLES TO DISK;
Query OK, 136 rows affected (0.01 sec)

ProxySQL> LOAD MYSQL SERVERS TO RUNTIME;
Query OK, 0 rows affected (0.01 sec)

Creating ProxySQL Client User

Provide read/write access to the cluster for ProxySQL, add this user on one of the Percona XtraDB Cluster nodes:

CREATE USER 'lbuser'@'192.168.56.115' IDENTIFIED BY 'lbpass';

GRANT ALL ON *.* TO 'lbuser'@'192.168.56.115';

Creating ProxySQL Client User:

ProxySQL> INSERT INTO mysql_users (username,password) VALUES ('lbuser','lbpass');
Query OK, 1 row affected (0.00 sec)
ProxySQL> LOAD MYSQL USERS TO RUNTIME;
Query OK, 0 rows affected (0.00 sec)
ProxySQL> SAVE MYSQL USERS TO DISK;
Query OK, 0 rows affected (0.02 sec)

confirm that the user has been set up correctly, you can try to log in:

[root@localhost ~]# mysql -u lbuser -plbpass -h 127.0.0.1 -P 6033
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 4
Server version: 5.5.30 (ProxySQL)

Copyright (c) 2009-2019 Percona LLC and/or its affiliates
Copyright (c) 2000, 2019, Oracle and/or its affiliates. All rights reserved.

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>

Let see to which node our client is going to connect of the cluster.

[root@localhost ~]# mysql -u lbuser -plbpass -h 127.0.0.1 -P 6033 -e "select @@hostname;";
mysql: [Warning] Using a password on the command line interface can be insecure.
+----------------------+
| @@hostname |
+----------------------+
| percona3.localdomain |
+----------------------+

you can see the proxy server is connected to percona3

I tried from another putty session then it gets connected to percona2:

[root@localhost ~]# mysql -u lbuser -plbpass -h 127.0.0.1 -P 6033 -e "select @@hostname;";
mysql: [Warning] Using a password on the command line interface can be insecure.
+----------------------+
| @@hostname |
+----------------------+
| percona2.localdomain |
+----------------------+

After a few multiple session it gets connected to percona1:

[root@localhost ~]# mysql -u lbuser -plbpass -h 127.0.0.1 -P 6033 -e "select @@hostname;";
mysql: [Warning] Using a password on the command line interface can be insecure.
+----------------------+
| @@hostname |
+----------------------+
| percona1.localdomain |
+----------------------+

Connecting from MySQL Workbench:

Below are the configure of my session in MySQL workbench:

I Tried to see which Node will connect from MySQL Workbench

Failover:

Now we will check how this will perform the failover

[root@percona3 mysql]# service mysql stop
Redirecting to /bin/systemctl stop mysql.service

ProxySQL> select hostgroup_id,hostname,port,status from runtime_mysql_servers;
+--------------+----------------+------+---------+
| hostgroup_id | hostname | port | status |
+--------------+----------------+------+---------+
| 0 | 192.168.56.110 | 3306 | ONLINE |
| 0 | 192.168.56.114 | 3306 | SHUNNED |
| 0 | 192.168.56.113 | 3306 | ONLINE |
+--------------+----------------+------+---------+
3 rows in set (0.01 sec)

Now let start the mysql on the node 3 again and check the cluster status again from proxy server

[root@percona3 mysql]#systemctl start mysql.service

ProxySQL> SELECT hostgroup_id hg,count(status) cnt from main.runtime_mysql_servers WHERE status = "ONLINE" GROUP BY hg having cnt ;
+----+-----+
| hg | cnt |
+----+-----+
| 0 | 3 |
+----+-----+
1 row in set (0.00 sec)

ProxySQL> select hostgroup_id,hostname,port,status from runtime_mysql_servers;
+--------------+----------------+------+--------+
| hostgroup_id | hostname | port | status |
+--------------+----------------+------+--------+
| 0 | 192.168.56.110 | 3306 | ONLINE |
| 0 | 192.168.56.114 | 3306 | ONLINE |
| 0 | 192.168.56.113 | 3306 | ONLINE |
+--------------+----------------+------+--------+
3 rows in set (0.00 sec)

NOTE: If you see the node status as SHUNNED then try to connect multiple time so the client gets the latest status of the cluster as runtime_mysql_servers store the latest status of the node when it was tried to connect last time.

Testing Cluster with sysbench:

yum install sysbench

sysbench requires ProxySQL client user credentials that you created (lbuser/lbpass) in Creating ProxySQL Client User.

sysbench /usr/share/sysbench/oltp_read_only.lua --threads=4 --mysql-host=127.0.0.1 
--mysql-user=lbuser --mysql-password=lbpass --mysql-port=6033 --tables=10 --table-size=10000 prepare

sysbench /usr/share/sysbench/oltp_read_only.lua --threads=4 --events=0 --time=300 --mysql-host=27.0.0.1 
--mysql-user=lbuser --mysql-password=lbpass --mysql-port=6033 --tables=10 
--table-size=10000 --range_selects=off --db-ps-mode=disable --report-interval=1 run

To see the number of commands that run on the cluster:

proxysql> SELECT * FROM stats_mysql_commands_counters;

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