Re: s6-rc-update initial findings

From: Colin Booth <>
Date: Thu, 17 Sep 2015 07:29:13 -0700

On Thu, Sep 17, 2015 at 3:40 AM, Laurent Bercot <> wrote:
> I could theoretically add a control command to s6-supervise to
> make it delay the execution of ./finish. But I don't think it would
> be worth it: it adds significant risks (what if a process sends a
> "block" command, then dies or otherwise fails to send an "unblock"
> command?), and complexity, for an extreme corner case that will
> probably never happen. If a ./finish failure is critical, the user
> should simply tell s6-rc-update to restart the service, which is
> 100% safe because the service directory will then be updated offline
> instead of live.
Makes sense. And no, the above isn't worth it. Actually, the corner
case is even more extreme than that. The failure doesn't rely on the
rare chance that a service terminates while it's getting updated, it
relies on the rare chance that the service terminates while it's
getting updated AND ./finish relies on stuff in ./data or ./env.


"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 Thu Sep 17 2015 - 14:29:13 UTC

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