go-init
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A minimal init system for containers with pre/post hooks
go-init
go-init is a minimal init system with simple lifecycle management heavily inspired by dumb-init.
It is designed to run as the first process (PID 1) inside a container.
It is lightweight (less than 500KB after UPX compression) and statically linked so you don't need to install any dependency.
Download
You can download the latest version on releases page
Why you need an init system
I can't explain it better than Yelp in dumb-init repo, so please read their explanation
Summary:
- Proper signal forwarding
- Orphaned zombies reaping
Why another minimal init system
In addition to init problematic, go-init tries to solve another Docker flaw by adding hooks on start and stop of the main process.
If you want to launch a command before the main process of your container and another one after the main process exit, you can't with Docker, see issue 6982
With go-init you can do that with "pre" and "post" hooks.
Usage
one command
$ go-init -main "my_command param1 param2"
pre-start and post-stop hooks
$ go-init -pre "my_pre_command param1" -main "my_command param1 param2" -post "my_post_command param1"
docker
Example of Dockerfile using go-init:
FROM alpine:latest
COPY go-init /bin/go-init
RUN chmod +x /bin/go-init
ENTRYPOINT ["go-init"]
CMD ["-pre", "echo hello world", "-main", "sleep 5", "-post", "echo I finished my sleep bye"]
Build it:
docker build -t go-init-example
Run it:
docker run go-init-example