hieulq / docker-salt

Dockerfiles to build service containers using SaltStack formulas

Build Docker images of SaltStack formulas

Trivial but working way to build docker images using existing SaltStack formulas.

Quickstart

Install docker, run ./build.sh and see what will happen :-)

Docker Compose

It uses host networking, so there must be replaced default ip address by local ip address on the machine.

sed -i 's,172.16.1.122,<your ip address>,g' compose/common.env

Then start compose-core.yml, after at least 30 seconds compose-openstack.yml and finally compose-opencontrail.yml

docker-compose -f compose-openstack.yml up -d

If you have issues with mysql, set SET GLOBAL max_connect_errors=100000; in mysql.

Images

salt-base

Base image will setup packages repository, install Salt formulas and configure Salt and Reclass so it's possible for per-service dockerfiles to execute salt states.

Main idea behind using this base image is that it will ensure that your whole infrastructure is built from the same version of formulas and metadata.

You can customize most of the things here:

• RECLASS_URL
  • URL to git repository of your reclass structure
• RECLASS_BRANCH
• REPO_URL
  • APT repository with SaltStack formula packages
• REPO_COMPONENTS

Per-formula

Per-service (aka per-formula) docker files are living in services directory, see services/postfix-server.dockerfile as an example.

Entrypoints

There are two supported ways for container post-creation actions (eg. database and users creation, etc.):

Salt-call entrypoint

To reuse what's done in formula and avoid rewriting the code into Bash-based entrypoint, you can call salt to finalize setup.

• [salt-base] will setup /sbin/service that will workaround absence of upstart and other init daemons and simply call script in /etc/init.d if present
  • therefore Salt service states should pass fine and start the services
  • if services are started fine by salt state run, it's possible to execute other actions (database creation, etc.)
• [salt-base] will set noservices: True grain so formulas can recognize they are running as a part of image build and will skip all actions that require running services
• [<service>-<role>] will generate pillar and it's top file into /srv/salt/pillar and remove reclass
  • so it's possible to run salt with all metadata that container needs but it will not have access to other containers' metadata
• [<service>-<role>] will run salt states
  • /entrypoint.sh is generated by service formula
• [<service>-<role>] remove noservices grain and do cleanup
• [container creation] when container is created, /entrypoint.sh is executed:
  • replace placeholders by environment variables in /srv/salt/pillar/<service>-<role>.sls
  • run salt.highstate to finalize provisioning
  • stop service started by salt run
  • start service on foreground in docker-way, keeping container running

Shell entrypoint

For services that don't need additional provisioning on container creation or where having SaltStack present in image is overhead, /entrypoint.sh can be simply generated using Jinja on salt run during image creation.

In that case, Salt with it's formulas and Reclass is purged at the end of image build.

Building pipeline