Re: process supervisor - considerations for docker

From: Gorka Lertxundi <glertxundi_at_gmail.com>
Date: Sun, 1 Mar 2015 10:13:24 +0100

Hi guys,

I haven't had much time this week due to work and now I am overwhelmed!

Yesterday, as Dreamcat4 has noticed, I've been working in a version that
gathers all the ideas covered here.

All,
* I already converted bash init scripts into execline and make use of
s6-utils instead of 'linux' ones to facilitate usage in another base images.
* It's important to have just _one_ codebase, this would help focusing
improvements and problems in one place. I extracted all the elements I
thought would be useful in a container environment. So, if you all feel
comfortable we could start discussing bugs, improvements or whatever there.
I called this project/repo container-s6-overlay-builder (
https://github.com/glerchundi/container-s6-overlay-builder).
* Now, and after abstracting 's6-overlay', using ubuntu with s6 is a matter
of extracting a tarball. container-base is using it already:
https://github.com/glerchundi/container-base/blob/master/Dockerfile#L73-L75.
* To sum up, we all agree with this. It is already implemented in the
overlay:
  - Case #1: Common case, start supervision tree up.
    docker run image
  - Case #2: Would start a shell without the supervision tree running
    docker run -ti --entrypoint="" base /bin/sh
  - Case #3: Would start a shell with the supervision tree up.
    docker run -ti image /bin/sh

Dreamcat4,
* Having a tarball with all the needed base elements to get s6 working is
the way to go!

Laurent,
* Having a github mirror repo is gonna help spreading the word!
* Although three init phases are working now I need your help with those
scripts, probably a lot of mistakes were done...
  -
https://github.com/glerchundi/container-s6-overlay-builder/tree/master/rootfs/etc/s6/.s6-init/init-stage1
  -
https://github.com/glerchundi/container-s6-overlay-builder/tree/master/rootfs/etc/s6/.s6-init/init-stage2
  -
https://github.com/glerchundi/container-s6-overlay-builder/tree/master/rootfs/etc/s6/.s6-init/init-stage3
* I've chosen /etc/s6/.s6-init as the destination folder for the init
scripts, would you like me to change?

John,
About github organization, I think this is not the place to discuss about
it. I really like the idea and I'm open to discuss it but first things
first, lets focus on finishing this first approach! Still, simple-d and
micro-d are good names but are tightly coupled to docker *-d, and rocket
being the relatively the new buzzword (kubernetes is going to support it)
maybe we need to reconsider them.

rgds,

2015-02-28 18:57 GMT+01:00 John Regan <john_at_jrjrtech.com>:

> Sweet. And yeah, as Laurent mentioned in the other email, it's the
> weekend. Setting dates for this kind of stuff is hard to do, I just
> work on this in my free time. It's done when it's done.
>
> I also agree that s6 is *not* a docker-specific tool, nor should it
> be. I'm thankful that Laurent's willing to listen to any ideas we
> might have re: s6 development, but like I said, the goal is *not*
> "make s6 a docker-specific tool"
>
> There's still a few high-level decisions to be made, too, before we
> really start any work:
>
> 1. Goals:
> * Are we going to make a series of s6 baseimages (like one
> based on Ubuntu, another on CentOS, Alpine, and so on)?
> * Should we pick a base distro and focus on creating a series of
> platform-oriented images, aimed more at developers (ie, a PHP image, a
> NodeJS image, etc)?
> * Or should be focus on creating a series of service-oriented
> images, ie, an image for running GitLab, an image for running an
> XMPP server, etc?
>
> Figuring out the overall, high-level focus early will be really
> helpful in the long run.
>
> Options 2 and 3 are somewhat related - you can't really get to 3
> (create service-oriented images) without getting through 2 (make
> platform-oriented images) anyway.
>
> It's not like a goal would be set in stone, either. If more guys want
> to get on board and help, we could alway sit down and re-evaluate.
> With more manpower, you could get into doing a whole series of
> distro-based, service-oriented images (ie, a Ubuntu XMPP server as
> well as an Alpine XMPP server).
>
> But given we're just a few guys, setting a straightforward small focus
> is probably the way to go. I would vote for either creating a series
> of baseimages, oriented towards other image-makers, or pick Alpine as
> a base, and focus on making small and efficient service-oriented
> images (ie, a 10MB XMPP service, something like that) aimed at
> sysadmins/users.
>
> But I'm open to any of those options, or others, so long as it's
> within the realm of possibility for just a few people working in their
> free time.
>
> 1. Should be form a GitHub org, and what should it be called?
>
> I vote yes, I'll go ahead and make it if you want.
>
> For the org name, I was thinking about starting a series of Alpine
> images aimed at users (like I said, 10MB chat service) under the org
> name "micro-d" (as in, Micro Docker containers), already. If that's the
> focus we go with, then that's probably a pretty OK name.
>
> If we go with doing a series of simple, easy-to-use baseimages aimed
> at other imagemakers, then probably something like "simple-d" (Simple
> Docker containers).
>
> Again, open to suggestions, those are just my initial ideas. The one
> thing I would advise against is using s6 in the name, since that
> would imply it's a project under the skarnet.org umbrella, which I
> don't think this is. It's outside that scope. We can promote how much
> we love s6 all we want in the docs, and blog posts, and so on, but
> we *shouldn't* do things like call our init "s6-init", name the image
> "s6-alpine", stuff like that.
>
> Once we figure out the high-level goals, we can set out a few more
> structural-type things.
>
> -John
>
Received on Sun Mar 01 2015 - 09:13:24 UTC

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