Salt Container-Map

Configuration management and implicit dependency setup for Docker containers in SaltStack.

Project: https://github.com/merll/salt-container-map

Docs: Basic usage is provided in the state module. Details about container configurations are available in the docs for Docker-Map.

Overview

This package contains SaltStack modules for configuring Docker containers. They do not replace, but complement Salt's built-in dockerio module in the following aspects:

• Container dependencies that have to be followed during startup and shutdown do not have to be modelled via require or require_in. Instead, these are implicitly defined through their shared volumes and links.
• For the purpose of sharing data between containers, virtual volumes can be created via a minimal runnable image (tianon/true obtained from the public Docker registry). These are considered during the dependency check and become adjusted with necessary file system permissions during startup.
• When the configuration of a container is modified, the affected containers and their dependents can automatically be shut down and recreated.
• Image updates can also result in an automated shutdown and recreation of containers and their dependents, without explicit watch or onchanges.

An example is documented in the state module.

Installation

Besides the usual package installation, a few simple post-installation steps are required. They are described in the docs.

Modules

Custom renderer

Container configurations can be set in both pillars and states. Pillars have the advantage that they are loaded automatically before any state (e.g. container_map.updated) or execution module uses it. Usually the disadvantage is that pillars cannot refer to other pillars. This package however provides a custom renderer lazy_yaml along with custom tags !pillar and !grain, which are resolved to their values on the minion just before the container maps and their configurations are instantiated.

By default, container maps are loaded from a pillar container_maps. This can be changed in the configuration by setting the configuration value container_map.pillar_name.

State and execution module

The modules distributed to the minions provide the functionality as outlined in the overview. A usage example is included in the state module documentation.