mariadb-galera

Clusterable, auto-discoverable MariaDB galera cluster - made for Docker Cloud

Built with the useful topic from Withblue.ink.

Project description

Goal of this project is to create an easily deployable MariaDB cluster, that can scale up and down without configuration/setup assle. It uses HOSTNAME (or DOCKERCLOUD_CONTAINER_HOSTNAME on Docker Cloud) env vars to discover other hosts (mariadb-1, mariadb-2, mariadb-3, etc.). Container named with {name}-1 will be the galera cluster creator.

The container is ready to use with Docker Cloud.

Build and run

Docker Cloud/Docker Compose YML

mariadb-production:
  environment:
    - MYSQL_ROOT_PASSWORD=password
  image: 'dialonce/mariadb-galera:latest'
  ports:
    - '3306:3306'
  volumes:
    - '/data/mysql:/data'

Then it should automatically grow as you scale it up.

Manual (to try it locally)

docker build -t dialonce/mariadb-galera:latest .
docker run -it -e MYSQL_ROOT_PASSWORD=root --name=mariadb-1 -e HOSTNAME=mariadb-1 --rm -p 3306:3306 dialonce/mariadb-galera:latest
docker run -it -e MYSQL_ALLOW_EMPTY_PASSWORD=true --name=mariadb-2 -e HOSTNAME=mariadb-2 --rm --link mariadb-1:mariadb-1 dialonce/mariadb-galera:latest

Env vars

Name	Example	Description
HOSTNAME	`mariadb-1`	The container hostname. Container named `{name}-1` will be the Galera master.
MYSQL_ROOT_PASSWORD	`pass`	The cluster root password.
MYSQL_ALLOW_EMPTY_PASSWORD	`anything`	Allow empty root password
MYSQL_RANDOM_ROOT_PASSWORD	`anything`	Generates a random root password
MYSQL_DATABASE	`anything`	A database name to create on first launch
MYSQL_USER	`username`	An user name to create on first launch. Must provide `MYSQL_PASSWORD` env var. If `MYSQL_DATABASE` is provided, it will be granted access to it
MARIADB_DEFAULT_STORAGE_ENGINE	`InnoDB`	The default storage engine to use for the node
GALERA_SLAVE_THREADS	`1`	Number of slave threads to start, see doc
MARIADB_INNODB_BUFFER_POOL_SIZE	`134217728`	The pool size of your InnoDB buffers (in bytes), see doc
MARIADB_INNODB_BUFFER_POOL_INSTANCES	`1`	The number of instances for your InnoDB buffers, see doc. Each should be at least 1GB of size (`POOL_SIZE`)

Things to know

Cluster shut down and clustering recovery

Never shut down the whole cluster - if you do so the nodes may not be able to recover. If for some reason you need to shut down the whole cluster and restart it later, make sure to delete the file named clustered located in shared volume of the first container ({name}-1).

Always set up a rolling deployment process to avoid any clustering shutdown in case of an update.

Setup examples

Behind a reverse proxy (HAProxy), secured by IP filtering

Creating a MariaDB Galera cluster behind a reverse proxy, that will load balancer and filter incoming requests based on source IP address:

mariadb-production:
  environment:
    - 'EXCLUDE_PORTS=4567,4568,4444'
    - 'EXTRA_SETTINGS=acl network_allowed src 192.168.1.0,block if !network_allowed'
    - MYSQL_ROOT_PASSWORD=password
    - TCP_PORTS=3306
  image: 'dialonce/mariadb-galera:latest'
  sequential_deployment: true
  volumes:
    - '/data/mysql:/data'
mariadb-production-lb:
  environment:
    - 'STATS_AUTH=user:pass'
    - STATS_PORT=1936
  image: 'dockercloud/haproxy:latest'
  links:
    - mariadb-production
  ports:
    - '1936:1936'
    - '3306:3306'
  roles:
    - global

dial-once/docker-mariadb-galera