Docker Salt-Master

A Docker image which allows you to run a containerised Salt-Master server.

Running the Container

You can easily run the container like so:

docker run --rm -it soon/salt-master

Environment Variables

The following environment variables can be set:

• LOG_LEVEL: The level to log at, defaults to error

Volumes

There are several volumes which can be mounted to Docker data container as described here: https://docs.docker.com/userguide/dockervolumes/. The following volumes can be mounted:

• /etc/salt/pki - This holds the Salt Minion authentication keys
• /var/cache/salt - Job and Minion data cache
• /var/logs/salt - Salts log directory
• /etc/salt/master.d - Master configuration include directory
• /srv/salt - Holds your states, pillars etc

Data Container

To create a data container you are going to want the thinnest possible docker image, simply run this docker command, which will download the simplest possible docker image:

docker run -v /etc/salt/pki -v /var/salt/cache -v /var/logs/salt -v /etc/salt/master.d -v /srv/salt --name salt-master-data busybox true

This will create a stopped container wwith the name of salt-master-data and will hold our persistant salt master data. Now we just need to run our master container with the --volumes-from command:

docker run --rm -it --volumes-from salt-master-data soon/salt-master

Sharing Local Folders

To share folders on your local system so you can have your own master configuration, states, pillars etc just alter the salt-master-data command:

docker run -v /etc/salt/pki -v /var/salt/cache -v /var/logs/salt -v /path/to/local:/etc/salt/master.d -v /path/to/local:/srv/salt --name salt-master-data busybox true

Now /path/to/local can hold your states and master configuration.

Ports

The following ports are exposed:

• 4505
• 4506

These ports allow minions to communicate with the Salt Master.

Running Salt Commands

Docker will hopefully soon ship with a docker exec command which will allow you to run commands in a running container. See this pull request: moby/moby#7409.

But until then you will need to run another docker container which runs a program called nsenter which allows you to connect to running containers. Follow the instructions here: https://github.com/jpetazzo/nsenter

Once installed run:

$ CONTAINER_ID=$(docker run -d soon/salt-master)
$ docker-enter $CONTAINER_ID
$ root@CONTAINER_ID:~# salt '*' test.ping
$ root@CONTAINER_ID:~# salt '*' grains.items