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.

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