Running services (upstart/init.d) in a container

Question

I'm trying to launch a system in docker that has many init and upstart services and I get this error.

initctl: Unable to connect to Upstart:
Failed to connect to socket /com/ubuntu/upstart: Connection refused

All the workarounds suggest making a hard link to /bin/true to silence the error. But I need to have these services managed by upstart for restart-ability and for upstart emit events to work...

As it seems docker does not support this, I'm considering the gross hack of writing a script to launch all the services in /etc/rcX.d and keep track of the PIDs. That doesn't solve lack of emit events from upstart.

Any other ideas how to launch upstart processes in docker?

Restive

The philosophy of docker is to run a process, if you want to run several, have a look at supervisor docs.docker.com/articles/using_supervisord – Bunt

supervisor seems mostly equivalent, if not a subset, of upstart, but thanks for the pointer; it might have to do. Given a large legacy system of init scripts, it's not ideal to convert them over and not doable to run them as individual dockers. – Restive

Answer 1

Unfortunately, upstart does not work inside of a docker container because they do some magic with the init system.

This issue explains:

If your application uses upstart, this wont fit well in bare docker images, and even more if they divert /sbin/init or /sbin/initctl to something like /bin/true or /dev/null. You application may use service to start if this one has an old school systemV initscript and if the initctl command has not been diverted.

In the case of salt-minion, on ubuntu the packaging uses an upstart job and no classical init script so it is normal that it wont start in both cases.

And this one says:

Because Docker replaces the default /sbin/init with its own, there's no way to run the Upstart init inside a Docker container.

Barren

Answer 2

You should definitely be able to do that. It's really not the way "Docker Way" but it's very possible. You might want to consider simply using the phusion/baseimage base image, it's got support for runit built in. If you'd rather use upstart just look at how they've implemented the entrypoint, /sbin/myinit, and follow that.

Chairman