CODEWITHSUNDEEP
docker
Greg
Greg

Reputation: 11512

How can I "inherit" starting processes in Docker?

I have a base Docker image, Base, that contains a supporting service 'helper' I want to run. This base is not intended for direct use.

If I build another image from Base, is there a way 'helper' can be set to auto-run on start without the author of this new image being aware of having to start it.

For example I know I can doctor the CMD to start 'helper' && then do whatever the author wants. I'm looking for a way to encapsulate starting 'helper' so the image author building on top of Base doesn't have to be aware or do anything.

Possible?

Upvotes: 2

Views: 51

Answers (1)

VonC
VonC

Reputation: 1324537

You can consider using as a base image phusion/baseimage-docker (which always starts the my_init script, to take care of the zombie processes)

In that image, you can define multiple program (daemon) to run:

You only have to write a small shell script which runs your daemon, and runit will keep it up and running for you, restarting it when it crashes, etc.

The shell script must be called run, must be executable, and is to be placed in the directory /etc/service/<NAME>.

If your base image has a /etc/service/helper/run script, then any image based on it would run helper, plus any other /etc/service/xxx/run script of your own.

Upvotes: 1

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