feat: Better management of entrypoint process

[VoVAllen]

Description

Currently multiple processes are managed under tini by concatenating multiple commands.

Cons:

• hard to inspect per-process logs
• hard to inspect errors when start the container

Candidate: https://github.com/F1bonacc1/process-compose

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[kemingy]

Another candidate: systemd.

[zwpaper]

systemd may not be a good option, supervisord or some other lightweight options like @VoVAllen mentioned https://github.com/F1bonacc1/process-compose may be better.

there is one more option mentioned in the SO, https://github.com/just-containers/s6-overlay, but I have never tried it before, just posted to be another candidate

ref: https://stackoverflow.com/a/51985145/4242336

[kemingy]

systemd may not be a good option, supervisord or some other lightweight options like @VoVAllen mentioned https://github.com/F1bonacc1/process-compose may be better.

I agree that systemd is heavy for this scenario. It looks okay to run systemd in the training or experimental task environments. I won't use it for the online serving containers.

Not sure if the pure Python application like supervisord can be a good fit for this.

there is one more option mentioned in the SO, https://github.com/just-containers/s6-overlay, but I have never tried it before, just posted to be another candidate

I like the idea "one thing per container" of s6. Will check this.

[gaocegege]

/cc @Zheaoli

[Zheaoli]

Not sure if the pure Python application like supervisord can be a good fit for this.

supervisord is not a good fit for this for two reasons:

1. too heavy
2. the code quality is not good

And I have already checked https://github.com/just-containers/s6-overlay. I think it is tiny enough for use, and it has basic signal management. But I think a little bit concern I have

1. the pure bash code will increase the difficulty for our customize action
2. I'm not sure S6 is good enough for the orphan process management

[kemingy]

And I have already checked https://github.com/just-containers/s6-overlay. I think it is tiny enough for use, and it has basic signal management. But I think a little bit concern I have

1. the pure bash code will increase the difficulty for our customize action

2. I'm not sure S6 is good enough for the orphan process management

s6 overlay is a shell wrapper for s6, which is written in C and includes lots of utilities.

My concern is that their configuration is crazy. I have no idea why they love the shell script so deeply.

Another option is Horust. Thanks to RiiR 🦀. The configuration is much easier. Although I know it may not be able to handle the signal very well. But this project is not active.