docker-skeleton

A docker skeleton - with best practice guide for writing dockerfile & entrypoint.

Assumptions:

• simple bash based entrypoint
• one to many services to be configured and started
• file based configuration files, modified by environment variables
• reliable, immutable bootstrapping
• fail fast & retry in entrypoint and for whole container

Keep it simple. Bash solves all your needs. No complex service or daemon for bootstrapping needed.

The entrypoint as a flow chart diagram:

Experiences

With the presented approach, we managed to build a real OpenStack test setup - with approx. 30 physical nodes and hence approx. 300 containers in total: Omistack.

TODOs and Extensions

• add side kick container skeleton to host (configuration) data
• extract execution steps out of entrypoint and allow their definition in simple yaml file