systemd (Was Re: tmpfs for strategic directories)

[seth vidal]

On Wed, 2010-05-26 at 18:20 +0200, Lennart Poettering wrote:
> On Wed, 26.05.10 15:52, Scott James Remnant (scott at canonical.com) wrote:
> 
> > On Wed, 2010-05-26 at 08:43 -0400, Matthias Clasen wrote:
> > 
> > > On Wed, 2010-05-26 at 12:35 +0100, Scott James Remnant wrote:
> > > 
> > > > We did sit down and discuss things, and you convinced me that
> > > > launchd-style activation was a useful thing to have.  Then you went off
> > > > and wrote systemd anyway.
> > > > 
> > > 
> > > If you want to add socket passing to upstart as well, we can turn this
> > > into a win-win situation instead of flaming each other. 
> > > 
> > > If both upstart systemd support this in the same way, it will will be
> > > much easier to get the patches for the various services upstream. That
> > > is great. 
> > > 
> > I don't see any reason not to at least pass the LISTEN_FDS environment
> > variable (though I can't figure out what LISTEN_PID is for?)
> 
> Ah nice, now we are talking, yesterday you were still refusing
> cooperation on this, and claimed the systemd scheme was "too simple"...
> 
> Regarding the LISTEN_PID env var:
> 
> environment variables are normally inherited when forking/execing. We
> want to make sure that only the process we actually start ourselves
> parses and handles LISTEN_FDS. We want to avoid that if this daemon
> might spawn some other process, it might get confused into handling
> LISTEN_FDS, although that env var wasn't actually intended for it.
> 
> And hence we say that LISTEN_PID should be verified first, and only if
> it matches LISTEN_FDS should be handled.
> 
> This is actually explained in my long blog story. Please read it. It's
> number 8 in the feature list!
> 
> > Upstart will support a different mechanism as well though, because for
> > the services we want to activate this way in Ubuntu, there are benefits
> > to having the services "phone back" to Upstart to pick up the socket.
> 
> Right, would be good if you could elaborate about that. I alead asked
> you a couple of times about this. Would love to hear about the
> reasoning.

Scott, Lennart,
  A Proposal: maybe the two of you should continue this discussion
off-list, in private. It may help facilitate more open communication
since neither of you will feel you have to respond to things for an
audience and you won't get any extraneous remarks from the peanut
gallery (like myself).
Perhaps there is more common ground than there appeared at first. If so
- feeling it out in private may help all of us.

Thanks,
-sv