This is a simple docker container that just runs exits successfully.

I use it with my docker-compose.override.yml files to not waste a bunch of resources when using a shared service during development.

For example, say I have the following docker-compose.yml file:

redis:
  image: redis:2.8

app:
  build: .
  links:
  - redis:redis

When I'm running this locally, I typically have a separate redis running that's being used by multiple other apps. So I'll add a docker-compose.override.yml like the following

redis:
  image: rwgrim/docker-noop

app:
  links: []
  external_links:
  -  redis:redis

What this does is remove all the existing links and then uses external_links to link to my already running redis container. However, since there is no way to disable a service with docker-compose, we override the redis in the docker-compose.yml to use the noop container which is tiny and exits immediately instead of sitting around wasting resources which can't be used by anything else.