anibali/maxscale repository overview

⁠MaxScale Docker image

Debian⁠ + MaxScale⁠

docker pull anibali/maxscale

• Includes full MaxScale install
• Supports linking MySQL replica containers
• Drop-in replacement for a standard MySQL container

If you are running a normal MySQL database instance, say something similar to the official Docker MySQL image⁠, then you should be able to use this as a drop-in replacement. MaxScale has some special awesome sauce which will automatically spread connections across multiple database replicas (and split read/writes as appropriate), but to your application it will just look like a normal database.

⁠Configuration

⁠Environment variables

When creating a container based on this Docker image, the following environment variables are expected:

• MYSQL_USER and MYSQL_PASS: MySQL username and password for connecting to the database and replicas.
• DB1_PORT_3306_TCP_ADDR and DB1_PORT_3306_TCP_PORT: Connection details for replication master.
• DB2_PORT_3306_TCP_ADDR and DB2_PORT_3306_TCP_PORT: Connection details for replication slave. Can add more as DB3, DB4, etc.

MaxScale expects a replication master and at least one replication slave.

⁠Usage

⁠Example 1: Replicas are in Docker containers

Linking to containers which have the MySQL replica running and listening on port 3306 will automatically inject most of the required environment variables.

db-proxy:
  image: anibali/maxscale
  environment:
    - MYSQL_USER=admin
    - MYSQL_PASS=password
  links:
    - db-master:db1
    - db-slave1:db2
    # ...can specify more slaves...
db-master:
  image: tutum/mysql
  environment:
    - REPLICATION_MASTER=true
    # ...
db-slave1:
  image: tutum/mysql
  environment:
    - REPLICATION_SLAVE=true
    # ...
  links:
    - db-master:mysql

⁠Example 2: Replicas are external to Docker

When the replicas are running outside of Docker you can manually tell the container where the replication master and slaves are. This is useful, for example, if the database is being run in Amazon RDS.

db-proxy:
  image: anibali/maxscale
  environment:
    - MYSQL_USER=admin
    - MYSQL_PASS=password
    - DB1_PORT_3306_TCP_ADDR=dbmaster.example.com
    - DB1_PORT_3306_TCP_PORT=3306
    - DB2_PORT_3306_TCP_ADDR=dbslave1.example.com
    - DB2_PORT_3306_TCP_PORT=3306
    # ...can specify more slaves...