eaglerock/salt-master repository overview

⁠Dockerized SaltStack Master Node

This Docker image starts up a simple Docker container running a SaltStack master node. The Dockerfile is loosely based off of the soon/salt-master Dockerfile, but updated to a newer version of Salt and using Debian as the base OS, rather than Ubuntu. Installing salt-master on Debian is a much simpler process as well.

⁠Ports

Ports 4505 and 4506 are used for communication between the Salt Master and the Salt Minions. These ports are exposed in the Docker image, and will need to be exposed either by your Docker host or through your orchestration suite (e.g. Docker Swarm or Kubernetes).

⁠Volumes

The following volumes are used in this install:

• /etc/salt/pki - Storage for master/minion keys, etc.
• /var/cache/salt - Salt cache directory
• /var/log/salt - Salt log directory
• /etc/salt/master.d - Master .conf file directory
• /srv/salt - Data directory used to hold states, pillars, and formulas

These volumes can easily be managed by an orchestration engine like Kubernetes. However, to run a single Docker container, it's recommended to set up a busybox container with the necessary volumes, then use the --volumes-from switch when creating the salt-master.

⁠Setting up a Data Container

Here is an example of how to set up a data container. I use a directory structure set up as follows:

salt
├── cache
├── logs
├── master.d
├── pki
└── srv

This allows all 5 directories to be persistent and easily managed from the host. Here is an example salt-minion-data container based on using this structure:

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

⁠Setting up the Salt Master

When setting up the salt-master on a Docker host with the salt-master-data container's volumes, run the following:

docker run -d --name salt-master --volumes-from salt-master-data \
           -p 4505:4505 -p 4506:4506 eaglerock/salt-master

Note that the two ports need to be mapped to to the host, otherwise the Master will not be able to communicate with its Minions.