What's the docker-compose equivalent of docker run --init?

Question

According to https://github.com/krallin/tini#using-tini, tini is built into docker, and can be used by passing the --init flag to docker run. In my case I'm using docker-compose and don't invoke docker run directly. How can I pass this flag?

Leak

Answer 1

If you are using version 2 of docker-compose, the configuration parameter is called init.

Example:

version: '2.2'
services:
  web:
    image: alpine:latest
    init: /usr/libexec/docker-init

Please see here for more details: https://docs.docker.com/compose/compose-file/compose-file-v2/#init

If you're using docker-compose version 3, apparently this has been removed and returned in version 3.7. Please refer to the following ticket: https://github.com/docker/docker.github.io/issues/3149

Bannasch

Ah, ok. It was removed from version 3 but from that ticket it sounds like it is being worked on. At the moment, the takeaway is: "While the --init option is not yet supported for services, you can add the tini binary to your images (see the README for tini)." – Leak

As of version 3.7, it's back. Just specify init: true for the appropriate service(s). (Requires Docker 18.06) – Soothsay

Do you know how to set the verbose mode for this service ? is it via a global docker verbose setting i cant seem to be able to find ? – Gunmaker

Answer 2

Here is an example from Docker Docs:

version: "2.4"
services:
  web:
    image: alpine:latest
    init: true

Ferrigno