Setting up MySQL Replication S ⭢ R1 and S ⭢ R2 with Docker MySQL images

Basic steps to spin up a minimal MySQL master-slave replication environment for experimentation:

• Docker installed and running

For detailed explanations, optional configuration, and troubleshooting, refer to the full article below.

1. Pull MySQL 5.7 image

   docker pull mysql/mysql-server:5.7

2. Create Docker network

   docker network create replicanet

3. Start containers (1 source + 2 replicas)

   docker run -d --rm --name=source --net=replicanet --hostname=source \
     -e MYSQL_ROOT_PASSWORD=mypass \
     mysql/mysql-server:5.7 \
     --server-id=1 \
     --log-bin='mysql-bin-1.log'
   
   docker run -d --rm --name=replica1 --net=replicanet --hostname=replica1 \
     -e MYSQL_ROOT_PASSWORD=mypass \
     mysql/mysql-server:5.7 \
     --server-id=2
   
   docker run -d --rm --name=replica2 --net=replicanet --hostname=replica2 \
     -e MYSQL_ROOT_PASSWORD=mypass \
     mysql/mysql-server:5.7 \
     --server-id=3

   Wait for all containers to show (healthy) in docker ps -a.

4. Configure source node

   docker exec -it source mysql -uroot -pmypass \
     -e "CREATE USER 'repl'@'%' IDENTIFIED BY 'replicapass';" \
     -e "GRANT REPLICATION SLAVE ON *.* TO 'repl'@'%';" \
     -e "SHOW MASTER STATUS;"

   Note the File (e.g., mysql-bin-1.000003) and Position values from the output.

5. Configure replicas Replace MASTER_LOG_FILE with the File value from the previous step:

   for N in 1 2; do
     docker exec -it replica$N mysql -uroot -pmypass \
       -e "CHANGE MASTER TO MASTER_HOST='source', MASTER_USER='repl', \
         MASTER_PASSWORD='replicapass', MASTER_LOG_FILE='mysql-bin-1.000003';" \
       -e "START SLAVE;"
   done

6. Verify replication Create a test database on the source:

   docker exec -it source mysql -uroot -pmypass -e "CREATE DATABASE TEST;"

   Check replicas for the new database:

   for N in 1 2; do
     docker exec -it replica$N mysql -uroot -pmypass -e "SHOW DATABASES;"
   done

7. Cleanup

   docker stop source replica1 replica2
   docker network rm replicanet
   docker rmi mysql/mysql-server:5.7