MaxScale/docker

MariaDB MaxScale Docker image

This Docker image runs MariaDB MaxScale. The MaxScale version used to build the image is an unreleased development build so this should not be used for a production system.

Usage

MaxScale is a proxy so its configuration is dependent on the use case and there is no generally valid default. The configuration file inside the image (shown in Default configuration) includes only the bare minimum to start MaxScale and has no useful services. The simplest way to add more to the configuration is to place another file (my_config.cnf) in a directory (/my_dir/) and then mount the directory to /etc/maxscale.cnf.d/ inside the container when starting it. MaxScale will add any files inside /etc/maxscale.cnf.d/ to its configuration.

docker run --network host --rm -v /my_dir:/etc/maxscale.cnf.d/ maxscale

In the examples, the Docker network mode is set to host so that the container has full network access (--network host).

To replace the configuration file completely, start MaxScale with -f <path_to_config>. Adding custom options removes all default options defined in the image. When adding new flags to MaxScale, one should add back -l stdout to print log to stdout.

docker run --network host --rm -v /my_dir:/container_dir maxscale -l stdout -f /container_dir/my_config.cnf

To save logs to /my_dir, remove the -l stdout and set /container_dir as log directory with the option -L /container_dir.

docker run --network host --rm -v /my_dir:/container_dir maxscale -L /container_dir -f /container_dir/my_config.cnf

Default configuration

# MaxScale documentation on GitHub:
# https://github.com/mariadb-corporation/MaxScale/blob/develop/Documentation/Documentation-Contents.md

# Complete list of configuration options:
# https://github.com/mariadb-corporation/MaxScale/blob/develop/Documentation/Getting-Started/Configuration-Guide.md

# Global parameters

[maxscale]
threads=2

# This service enables the use of the MaxAdmin interface
# MaxScale administration guide:
# https://github.com/mariadb-corporation/MaxScale/blob/develop/Documentation/Reference/MaxAdmin.md
[MaxAdmin-Service]
type=service
router=cli

[MaxAdmin-Listener]
type=listener
service=MaxAdmin-Service
protocol=maxscaled
socket=default

Example configuration extension

# Server definitions
# Set the address of the server to the network address of a MySQL server.

[server1]
type=server
address=127.0.0.1
port=3306
protocol=MySQLBackend

# Monitor for the servers
# This will keep MaxScale aware of the state of the servers.
# MySQL Monitor documentation:
# https://github.com/mariadb-corporation/MaxScale/blob/develop/Documentation/Monitors/MySQL-Monitor.md

[MySQL-Monitor]
type=monitor
module=mysqlmon
servers=server1
user=myuser
passwd=mypwd
monitor_interval=1000

# Service definitions
# Service Definition for a read-only service and a read/write splitting service.

# ReadConnRoute documentation:
# https://github.com/mariadb-corporation/MaxScale/blob/develop/Documentation/Routers/ReadConnRoute.md

[Read-Only-Service]
type=service
router=readconnroute
servers=server1
user=myuser
passwd=mypwd
router_options=slave

# ReadWriteSplit documentation:
# https://github.com/mariadb-corporation/MaxScale/blob/develop/Documentation/Routers/ReadWriteSplit.md

[Read-Write-Service]
type=service
router=readwritesplit
servers=server1
user=myuser
passwd=mypwd
max_slave_connections=100%

# Listener definitions for the services
# Listeners represent the ports the services will listen on.

[Read-Only-Listener]
type=listener
service=Read-Only-Service
protocol=MySQLClient
port=4008

[Read-Write-Listener]
type=listener
service=Read-Write-Service
protocol=MySQLClient
port=4006