From: Pete Zaitcev <zaitcev@redhat.com>
To: Project Hail List <hail-devel@vger.kernel.org>
Cc: iwhd-devel@lists.fedorahosted.org
Subject: Autostart
Date: Wed, 29 Sep 2010 17:09:36 -0600 [thread overview]
Message-ID: <20100929170936.0ce1d2a9@lembas.zaitcev.lan> (raw)
Jeff et.al.:
I am working on a feature called "autostart" in Image Warehouse. It amounts
to iwhd starting with a certain default configuration, but is a bit more:
it also launches services necessary to support said default, e.g. tabled.
Naturally, tabled needs cld and chunkd.
An interesting question is what to do when iwhd exits. I decided not to
kill what was started. So, we have a little self-contained cell of
tabled, chunkd, S3, based off a certain local directory or other
namespace anchor. Therefore, when iwhd restarts, it tests if the
cell is still there, and uses that. It also tests if the service
started successfuly, using the same method.
As we see, for each service iwhd starts, it needs to verify that
it's available (either before spawning it, or after). This would be
done best by talking to the service. But iwhd only has S3 client,
and no CLD client, so it cannot talk to cld (or chunkd). I had an idea:
add an autostart feature to tabled.
Tabled knows how to talk to both chunkd and cld, so it can verify
that they are running. It would not be that much code. The downside
is that it's clearly a special case, encoding of a policy. So I am
asking how objectionable it would be (including do we want tabled -a
for tests... they kinda run ok as they are).
Cheers,
-- Pete
next reply other threads:[~2010-09-29 23:09 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-09-29 23:09 Pete Zaitcev [this message]
2010-09-30 21:39 ` Autostart Jeff Garzik
2010-09-30 22:47 ` Autostart Pete Zaitcev
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