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Load Balance MySQL Using HAProxy

Load Balance HA MySQL with HAProxy.

HAProxy or High Availability Proxy is a high performance open-source load balancer created to work (load balance) over TCP/HTTP. This is a Software that has several use cases you can chose, but it's great for a MySQL load balancer. The company who makes HAProxy also develops many more products paid and free. Now for this lab we will use the community version as load balancer software on our servers. The key theme for this post will be HAProxy Docker to Load Balance MySQL. In other words a lab of HAProxy, Docker and MySQL.

In general Load Balancers power the uptime of organizations with large infrastructures and enormous traffic demands by giving them the flexibility and confidence to deliver websites and applications with high availability, performance and security at any scale in any environment. Many companies use load balancers in their product delivery process. You can check this article to configure a Master-Slave on MySQL.

haproxy load balance mysql docker

In this post, we will create a master replication master on MySQL and make MySQL load balancer replication with HAProxy. Load balance is useful if we want to create a reliable database with multiple MySQL services on multiple instances or servers. For this purpose, I have used docker to create a load balance with HAProxy and MySQL. However, you can also deploy it on an AWS instance or server without running docker.

Okay, let's get started with creating a Master-Master replication with load balance on HAProxy using MySQL.

Note: I am using Ubuntu Server 18.04 LTS when creating this article.

How To Load Balance with MySQL: Editing The Docker-Compose yml File

If we create MySQL replication with HAProxy load balancer to load Balance using docker containers. The easiest way or you could even say best way for a lab is to make it is to use Docker Compose. This way you configure docker to create multiple containers using a dot yml (yaml) configuration file.

Docker compose helps us in managing containers in docker. You can edit the configuration in docker compose file. Let's create docker compose files for MySQL and HAProxy containers by following the steps below.

version: '3.9'
services:
  mysql-master1:
    image: mysql:8.0
    container_name: mysql-master1
    restart: unless-stopped
    env_file: master1/.env
    command: --default-authentication-plugin=mysql_native_password
    cap_add:
      - all
    volumes:
      - ./master1/my.cnf:/etc/mysql/my.cnf
      - ./master1/data:/var/lib/mysql
    environment:
      - TZ:${TZ}
      - MYSQL_USER:${MYSQL_USER}
      - MYSQL_PASSWORD:${MYSQL_PASSWORD}
      - MYSQL_ROOT_PASSWORD:${MYSQL_PASSWORD}
    networks:
      default:
        aliases:
          - mysql

  mysql-master2:
    image: mysql:8.0
    container_name: mysql-master2
    restart: unless-stopped
    command: --default-authentication-plugin=mysql_native_password
    env_file: master2/.env
    cap_add: 
      - all
    volumes:
      - ./master2/my.cnf:/etc/mysql/my.cnf
      - ./master2/data:/var/lib/mysql
    environment:
      - TZ:${TZ}
      - MYSQL_USER:${MYSQL_USER}
      - MYSQL_PASSWORD:${MYSQL_PASSWORD}
      - MYSQL_ROOT_PASSWORD:${MYSQL_PASSWORD}
    networks:
      default:
        aliases:
          - mysql

  haproxy:
    image: haproxytech/haproxy-ubuntu:latest
    container_name: haproxy
    restart: unless-stopped
    ports: 
      - "2999:2999"
    cap_add:
      - all
    volumes:
      - ./haproxy.cfg:/etc/haproxy/haproxy.cfg
    networks:
      default:
        aliases:
          - mysql

Creating MySQL Master 1 Config for Load Balance with MySQL

I have used the latest version of MySQL to create a Master-Master MySQL-Replication on server 1. To make it easier to install MySQL, I used docker and created a persistent volume to allow the data in the container to be stored on the host server.

Additionally, create a persistent volume for my.cnf to connect to the container. Create a master1 folder to store data on MySQL replication on Master 1.

[email protected]: mkdir /data/haproxy-mysql/master1
create directory master1 load balance mysql

Create a data folder in the Master 1 directory; this data folder is useful for storing persistent volumes from the MySQL master 1 container to the host server.

[email protected]: mkdir /data/haproxy-mysql/master1/data
create data directory in master1 load balance mysql

Moreover, we need a custom configuration file in my.cnf on the host server that will create a persistent volume on the container.

[email protected]: touch /data/haproxy-mysql/master1/my.cnf
Create my.cnf file master1 load balance mysql

After that, open the my.cnf file and add configuration to my.cnf file to do replication on MySQL Master 1.

# Copyright (c) 2017, Oracle and/or its affiliates. All rights reserved.
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; version 2 of the License.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program; if not, write to the Free Software
# Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301 USA

#
# The MySQL  Server configuration file.
#
# For explanations see
# http://dev.mysql.com/doc/mysql/en/server-system-variables.html

[mysqld]
pid-file        = /var/run/mysqld/mysqld.pid
socket          = /var/run/mysqld/mysqld.sock
datadir         = /var/lib/mysql
secure-file-priv= NULL
server-id=1
binlog_format=ROW
log-bin
skip-name-resolve
# Custom config should go here
!includedir /etc/mysql/conf.d/

Then, create an environment variable (env) file to store the environment username and password in MySQL. As such, this lasts for the duration of terminal.

[email protected]:~$ touch /data/haproxy-mysql/master2/.env
env file master 1 load balance mysql

Moreover, fill the env file on Master 1 like this:


### WORKSPACE #############################################
TZ=UTC

#MYSQL_DATABASE=master
MYSQL_USER=master
[email protected]
MYSQL_PORT=3306
MYSQL_ROOT_PASSWORD=Mastermaster123

The following is a tree view in the Master 1 directory for MySQL master1 replication.

tree view on master 1 mysql load balance mysql

Create Master 2 MySQL Config File

Since we have made the configuration on mysql master 1, let's make the configuration on MySQl Master 2 now.

To do this, create a Master 1 folder with this command:

[email protected]:~$ mkdir /data/haproxy-mysql/master2
Create master2 folder mysql load balance mysql

In addition, create a data folder in the Master 2 directory to create a persistent volume on mysql master2.

[email protected]:~$ mkdir /data/haproxy-mysql/master2/data
create data folder on master2 load balance mysql

Therefore, don't forget to create my.cnf file for MySQL Master 2 replication configuration.

[email protected]:~$ touch /data/haproxy-mysql/master2/my.cnf
create my.cnf file on master2 load balance mysql

Add the contents of the my.cnf configuration as below.

# Copyright (c) 2017, Oracle and/or its affiliates. All rights reserved.
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; version 2 of the License.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program; if not, write to the Free Software
# Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301 USA

#
# The MySQL  Server configuration file.
#
# For explanations see
# http://dev.mysql.com/doc/mysql/en/server-system-variables.html

[mysqld]
pid-file        = /var/run/mysqld/mysqld.pid
socket          = /var/run/mysqld/mysqld.sock
datadir         = /var/lib/mysql
secure-file-priv= NULL
server-id=2
binlog_format=ROW
log-bin
skip-name-resolve
# Custom config should go here
!includedir /etc/mysql/conf.d/

In addition, create env file for MySQL Master 2.

[email protected]:~$ touch /data/haproxy-mysql/master2/.env
env file on master2 load balance mysql

Let's fill in the environment username and password in the env file master2.

### WORKSPACE #############################################
TZ=UTC

#MYSQL_DATABASE=master
MYSQL_USER=master
[email protected]
MYSQL_PORT=3306
MYSQL_ROOT_PASSWORD=Mastermaster123

Congratulations! You have created the replication configuration on MySQL Master 2. You can verify by using the tree:

tree directory mysql load balance mysql

Make Build Up Container for Load Balance on MySQL

Before you make docker-compose, change the permissions of the Master 1 and Master 2 folders according to the user on your server first with chown.

[email protected]:/data/haproxy-mysql$ sudo chown -R $(whoami): master*
change permision user mysql load balance

Not only that, but also change the data access rights so that it can be read by the container with this command (like the problems in Stack Overflow).

ubunt[email protected]:/data/haproxy-mysql$ chmod -R a+rwx master1/data/
[email protected]:/data/haproxy-mysql$ chmod -R a+rwx master2/data/
chmod data mysql load balance mysql

We have made all the configurations of docker compose and the mysql folder structure, let's build using docker compose. We go to the haproxy-mysql directory then run the command "docker-compose up -d".

[email protected]:/data/haproxy-mysql$ docker-compose up -d
docker compose mysql load balance mysql

Let's see the service container can run properly with the command "docker-compose ps".

[email protected]:/data/haproxy-mysql$ docker-compose ps
docker compose ps

The container is running fine, then we need to make a replication configuration on mysql. We will make a master master replication first before heading to loadbalance with haproxy.

Create Replications on MySQL

This is where you will enter the configuration stage in MySQL. Enter the MySQL Master 1 container to create the haproxy_user user. Then, enter the MySQL container with the root user and password that you added to the master1/.env file.

[email protected]:/data/haproxy-mysql$ docker-compose exec mysql-master1 bash
docker compose exec mysql 1

In this step you will create the user haproxy_user on mysql master1 by logging in using the root user firstL

mysql -u root -p
mysql 1 root login load balance mysql

Hence, create a new user "replication" on Master 1 MySQL

CREATE USER 'replication'@'%' IDENTIFIED WITH mysql_native_password BY 'Slaverepl123';
create user mysql load balance mysql

Let's allow user replication so that you can use it as replication in MySQL.

mysql> GRANT REPLICATION SLAVE ON *.* to 'replication'@'%';
grant user replication

After creating slave on MySQL master1, check master slave status on MySQL Master 1.

mysql> SHOW MASTER STATUS;
Show master status mysql

Then, go to MySQL Master 2 to create user replications and allow master master replications. Similarly, enter into the mysql-master2 container now.

[email protected]:/data/haproxy-mysql$ docker-compose exec mysql-master2 bash

Subsequently, login to the root user on MySQL Master 2.

[email protected]:/# mysql -u root -p
login into mysql master2

Create user replications on master2 mysql.

mysql> CREATE USER 'replication'@'%' IDENTIFIED WITH mysql_native_password BY 'Slaverepl123';
create user replication

After that, grant replication slave on Master2 MySQL with user MySQL.

mysql> GRANT REPLICATION SLAVE ON *.* to 'replication'@'%';
grant all replication

Congratulations! You have created user replications and granted replication slaves on MySQL Master 2. To confirm, let's see the status of the master.

mysql> SHOW MASTER STATUS;
show master status mysql2

Now, stop the slave on MySQL Master 1.

mysql> STOP SLAVE;
stop slave on mysql1

Accessing The Slave Logs on Master 1

You can access the initial bin log and slave position on MySQ with master slave log on MySQL Master 1.

mysql> CHANGE MASTER TO MASTER_HOST = 'mysql-master1', MASTER_USER = 'replication', MASTER_PASSWORD = 'Slaverepl123', MASTER_LOG_FILE = '6e360f05f522-bin.000001', MASTER_LOG_POS = 673;
change master mysql

Then, start the slave on MySQL Master 1.

mysql> START SLAVE;

After doing that, check the status of the slave on MySQL Master 1.

mysql> SHOW SLAVE STATUS \G;
mysql2 success replication

Accessing The Slave Logs on Master 2

You can access the initial bin log and slave positions on MySQL 1 with master slave log on MySQL Master 2.

mysql> CHANGE MASTER TO MASTER_HOST = 'mysql-master2', MASTER_USER = 'replication', MASTER_PASSWORD = 'Slaverepl123', MASTER_LOG_FILE = 'f9ce66dff73f-bin.000001', MASTER_LOG_POS = 673;
change master mysql

In addition, start slave on MySQL Master 1.

mysql> START SLAVE;

You can examine the slave status on MySQL Master 1 now.

mysql> SHOW SLAVE STATUS \G;
Mysql replication success load balance mysql

Likewise, now you can stop the slave on MySQL Master 2.

stop slave on mysql2 load balance mysql

Creating The HAProxy User for HAProxy docker container to use.

With this step you will get to create the user haproxy_user on Master 1.

mysql> CREATE USER 'haproxy_user'@'%';
create haproxy user load balance mysql

Likewise, create a user haproxy_root-- where only haproxy instances will be able to use the haproxy_root user.

mysql> CREATE USER 'haproxy_root'@'%' IDENTIFIED WITH mysql_native_password BY 'Haproxymysql123';
create user haproxy_root load balance mysql

To confirm this step, write a query to fetch the users list in MySQL Master 1 which will be synchronized to MySQL Master 2.

mysql> SELECT DISTINCT User FROM mysql.user;

Here's how the output looks on MySQL Master 1.

show user mysql1 load balance mysql

Similarly, this is the output on MySQL Master 2.

show user mysql2 load balance mysql

HAProxy MySQL; Configure The HAProxy to Load Balance

How cool is that? You have successfully created a MySQL replication with Master-Master for your haproxy mysql setup.

Therefore, the logical next step is to configure haproxy to make MySQL Loadbalance with TCO.

To do this, you will have to enter the haproxy container.

[email protected]:/data/haproxy-mysql$ docker-compose exec haproxy bash
docker exec haproxy load balance mysql

Great! With that done, let's start configuring loadbalance on haproxy.

Firstly, open haproxy configuration path at /etc/haproxy/haproxy.cfg.

[email protected]:/# vi /etc/haproxy/haproxy.cfg
config haproxy file load balance mysql

Then, add the configuration to the path /etc/haproxy/haproxy.cfg shown below. This will be used by the HAProxy docker container.

#---------------------------------------------------------------------
# Example configuration for a possible web application.  See the
# full configuration options online.
#
#   https://www.haproxy.org/download/1.8/doc/configuration.txt
#
#---------------------------------------------------------------------

#---------------------------------------------------------------------
# Global settings
#---------------------------------------------------------------------
global
    # to have these messages end up in /var/log/haproxy.log you will
    # need to:
    #
    # 1) configure syslog to accept network log events.  This is done
    #    by adding the '-r' option to the SYSLOGD_OPTIONS in
    #    /etc/sysconfig/syslog
    #
    # 2) configure local2 events to go to the /var/log/haproxy.log
    #   file. A line like the following can be added to
    #   /etc/sysconfig/syslog
    #
    #    local2.*                       /var/log/haproxy.log
    #
    log         127.0.0.1 local2

    chroot      /var/lib/haproxy
    pidfile     /var/run/haproxy.pid
    maxconn     4000
    user        haproxy
    group       haproxy
    daemon

    # turn on stats unix socket
    stats socket /var/lib/haproxy/stats

    # utilize system-wide crypto-policies
    ssl-default-bind-ciphers PROFILE=SYSTEM
    ssl-default-server-ciphers PROFILE=SYSTEM

#---------------------------------------------------------------------
# common defaults that all the 'listen' and 'backend' sections will
# use if not designated in their block
#---------------------------------------------------------------------
defaults
    #mode                    http
    log                     global
    option                  tcplog
    retries                 2
    timeout connect         4s
    timeout client          30m #1440m
    timeout server          30m #1440m
    timeout check           10s
    #maxconn                 3000

listen stats
    mode		http
    bind		*:2999
    stats		enable
    stats		uri /stats
    stats	realm	Strictly\ Private
    stats	auth	devops:[email protected]

listen mysql-cluster
    mode 	tcp
    option	tcpka
    bind		*:3306
    option	mysql-check	user	haproxy_user
    balance	roundrobin
    server	master1		mysql-master1:3306	check
    server	master2		mysql-master2:3306	check

Here, it is crucial to validate the haproxy configuration with this command below:

[email protected]:/# haproxy -c -V -f /etc/haproxy/haproxy.cfg
checking configure haproxy load balance mysql

After confirming that the haproxy configuration is valid, restart the haproxy container so that the TCP Loadbalance on port 3306 can run on haproxy.

[email protected]:/data/haproxy-mysql$ docker-compose restart haproxy
restart haproxy container load balance mysql

After restarting, check if port 3306 is running on the haproxy container.

[email protected]:/# netstat -ntlp
checking port with netstat load balance mysql

In the same way, try to test with the MySQL client-- to test it we need to install MySQL client on haproxy.

[email protected]:/# apt update && apt install mysql-client -y
Install mysql-client haproxy load balance mysql

In the end, check for the server_id using this command:

[email protected]:/# mysql -u root -p -h 127.0.0.1 -e "show variables like 'server_id'";
show varables server_id mysql load balance

Note: You can also check HAProxy docker container stats on the browser using Server IP.

haproxy stats dashboard loadbalance

Conclusion

In conclusion, it is safe to say HAProxy is quite useful for HTTP and TCP Loadbalancers. This way we can use it for TCP loadbalance on MySQL with Master-Master replication on MySQL. Besides being useful for simplifying the development process, you can also make MySQL work powerfully. I hope you liked this post and were able to follow along.

Finally feel free to check out the HAProxy Load balance using MySQL code on github.

Edited by: Syed Umar Bukhari

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