48 lines
1.8 KiB
Markdown
48 lines
1.8 KiB
Markdown
# runsvinit [](https://circleci.com/gh/peterbourgon/runsvinit)
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If you have a Docker container that's a collection of runit-supervised daemons, this process is suitable for use as the ENTRYPOINT.
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See [the example](https://github.com/peterbourgon/runsvinit/tree/master/example).
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**Why not use runit(8) directly?**
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[runit(8)](http://smarden.org/runit/runit.8.html) is designed to be used as process 1.
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And, if you provide an `/etc/service/ctrlaltdel` script, it will be executed when runit receives the INT signal.
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So, we could use that hook to gracefully terminate our services.
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But Docker only sends TERM on `docker stop`.
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Note that the container stop signal [will become configurable](https://github.com/docker/docker/pull/15307) in Docker 1.9.
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Once Docker 1.9 ships, this utility will be obsolete.
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**Why not just exec runsvdir(8) directly?**
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If [runsvdir(8)](http://smarden.org/runit/runsvdir.8.html) receives a signal, it doesn't wait for its supervised processes to exit before returning.
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**Why not wrap runsvdir(8) in a simple shell script?**
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Process 1 has the additional responsibility of [reaping orphaned child processes](https://blog.phusion.nl/2015/01/20/docker-and-the-pid-1-zombie-reaping-problem/).
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To the best of my knowledge, there is no sane way to do this with a shell script.
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Otherwise, indeed, this would work great:
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```sh
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#!/bin/sh
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sv_stop() {
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for s in $(ls -d /etc/service/*)
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do
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/sbin/sv stop $s
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done
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}
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trap "sv_stop; exit" SIGTERM
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/sbin/runsvdir /etc/service &
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wait
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```
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**Why not use my_init from [phusion/baseimage-docker](https://github.com/phusion/baseimage-docker)?**
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my_init depends on Python 3, which might be a big dependency for such a small responsibility.
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**So this is just a stripped-down my_init in Go?**
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Basically, yes.
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