Set up MySql Master-Slave on Docker

For this instruction, I will create 2 MySQL containner to use as Master - Slave.
The master and slave environment is dependence from each other,
so I will prepare the setting file for both environment in separate folder.

mysql-docker/
|--master/
|  |--Dockerfile
|  |--build.sh
|  |--exec-mysql.sh
|  |--run.sh
|  |--my.cnf
|  |--init-user.sql
|
|--slave/
   |--Dockerfile
   |--build.sh
   |--exec-mysql.sh
   |--run.sh
   |--my.cnf
   |--init-user.sql   

Prepare Setting Files:
We will prepare this following files for both master and slave environment.

Dockerfile (for building Docker containnner)

  FROM mysql/mysql-server:5.7.17
  COPY my.cnf /etc/my.cnf
  ENV MYSQL_ROOT_PASSWORD={your root password}
  COPY ./*.sql /docker-entrypoint-initdb.d/

build.sh (for building Docker containner)

MASTER
```
  docker build -t db_master .
```
SLAVE
```
  docker build -t db_slave .
```

exec-mysql.sh (for easily running mysql from terminal)

MASTER

  docker exec -it db_master sh -c "mysql -uroot -p{you root password}";

SLAVE

  docker exec -it db_slave sh -c "mysql -uroot -p{you root password}";

run.sh (for running the docker containner) When running we need to prepare folder for MASTER and SLAVE to save on local.
- MASTER Master can be accessed on 3306 on local port
```
  docker run --name db_master -p 3306:3306 -v /var/mysql/master:/var/lib/mysql -d db-master
```
- SLAVE Slave can be accessed on 3307 on local port
```
  docker run --name db_slave -p 3307:3306 -v /var/mysql/slave:/var/lib/mysql -d db-slave
```

my.cnf (MySQL’s configuration files)

MASTER

  [mysqld]
  server-id=1
  binlog_format=ROW
  log-bin
  ...//Anything Else

SLAVE

  [mysqld]
  server-id=2
  ...//Anything Else

init-user.sql (for creating user when build the Docker containner)

  CREATE USER 'root'@'%' IDENTIFIED BY '{your root password}';
  GRANT ALL PRIVILEGES ON *.* TO 'root'@'%' WITH GRANT OPTION; 

Builing Time

For MASTER

Build containner by
```
  $ bash build.sh
```
Start containner by
```
  $ bash run.sh
```
Open mysql command by
```
  $ bash exec-sql.sh
```

Check log binary and position Now we need only File,Position for setting in Slave.

  $mysql> SHOW MASTER STATUS\G
  ....
  File: master-bin.000001
  Position: 1512
  ....

For SLAVE

We will do 1~3 as same as we did in MASTER.

Then, Setting MASTER for SLAVE DB

  $mysql> CHANGE MASTER TO master_host="{master}",master_user="root",master_password="{slave root pwd}",master_log_file="master-bin.000001",master_log_pos=1512;

Start slave
```
  $mysql> START SLAVE;
```

Check Slave status and process

  $mysql> SHOW SLAVE STATUS\G;
  $mysql> SHOW PROCESSLIST\G;

Extra

 $ docker exec -ti db_master 'mysql' -uroot -p{root password} -e "SHOW MASTER STATUS\G" | grep File |awk '{print $2}'
 $ docker exec -ti db_master 'mysql' -uroot -p{root password} -e "SHOW MASTER STATUS\G" | grep Position |awk '{print $2}'

Auycro

Set up MySql Master-Slave on Docker