Re: [announce] s6-rc: a s6-based service manager for Unix systems

From: Colin Booth <>
Date: Tue, 29 Sep 2015 13:47:21 -0700

On Tue, Sep 29, 2015 at 11:59 AM, Avery Payne <> wrote:
> Having gone through that pain last year (Debian 7/Debian 8), I could chip in
> a few pointers.
Similar, though Debian Unstable here. I've also been running s6-rc
since about two hours after it was announced for inital testing back
in, what, July?
> 2. Debian *will* overwrite your boot arrangement if you retain whatever
> "stock" init system they are using. It does this for both the old way
> (Deb7/SysV) and the new way (Deb8/systemd). The only solutions are to
> either be vigilant about what is updated, pin the init system in apt (which
> prevents updates to it), or stop using dual-inits (which has its own
> issues).
Kernel init= lines in your grub config are your friend.
> 3. Apt-get on 7 will attempt to call init.d scripts unless you disable them
> explicitly. I have no clue how to get around this in 8 but I suspect
> there's a way to deal with that too. It will continue to do this even after
> the init system is stripped out. So each upgrade becomes an obstacle course
> with extra steps to deal with.
As long as you're running Debian 8 with sysvinit it's the same
mechanism as Debian 7. Not sure the systemd method but if it's not
running you're probably safe.
> 4. Debian's past discussions have made it fairly clear that while they will
> be happy to allow you to have your own init/supervisor arrangement, they
> won't lift a finger to support it. I don't follow these discussions
> entirely so it may have changed in the last few months. But this means that
> the behaviors in (2) and (3) will most likely continue.
Yup, and hence my explorations as to what exactly the pain points are
going to be for folks who aren't professional system administrators
and want to play around with s6 as an alternative init.
> 5. I think the only way out of this silly situation is the creation of .debs
> with your init/supervisor, and include some support scripts in them to
> intercept whatever brain damage apt-get seems to be enduring with regard to
> restarting daemons after upgrading them. Given the situation that Gerrit
> already has runit as a deb /and/ it requires a lot of hand-holding to
> integrate the "official" deb into the system, I see this being a slightly
> uphill battle for s6.
It's not quite as bad as you think. If you disable all your supervised
daemons via update-rc.d (or the systemd equivalent) and then pay
attention when you update your packages, it's pretty easy to recycle
updated processes. I've been doing that one on
supervised-but-stock-init computers for years. The situation doesn't
change when you're swapping out the init as well, it just requires a
bit more vigilance.


"If the doors of perception were cleansed every thing would appear to
man as it is, infinite. For man has closed himself up, till he sees
all things thru' narrow chinks of his cavern."
  --  William Blake
Received on Tue Sep 29 2015 - 20:47:21 UTC

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