Re: The "Unix Philosophy 2020" document

From: Alex Suykov <>
Date: Sat, 28 Dec 2019 15:37:35 +0200

Sat, Dec 28, 2019 at 01:46:08AM -0500, Steve Litt wrote:

> * No if any code within the s6 stack must be changed. So much good
> software has gone bad trying to incorporate features for only the
> purpose of getting new users.

It does not require any changes to s6. That's a major point I'd like
to demonstrate with this tool. A 200 C LOC external tool is enough to
let any process supervisor become a cgroup supervisor, on case-by-case
basis, just by chain-execing the tool with the application being

What the tool itself does is fork-spawning the chained application
and then waiting until cgroup is empty. While also proxying signals.
For the supervisor, it looks and behaves like a regular long-running
process. The supervisor does not need to know anything about cgroups.

The reason I think it's mostly useless is because the only use case
for cgroup supervision is supervising double-forking daemons, which
is not a very smart thing to do. A much better approach is to get rid
of double-forking and then just directly supervise the resulting long
running process.
I can't think of any other cases where it would be useful.
Received on Sat Dec 28 2019 - 13:37:35 UTC

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