Re: [Xen-devel] [PATCH] add domain creation/shutdown script execution su
On Tue, Mar 06, 2007 at 03:39:38PM +0000, Mark Williamson wrote:
> Yes, the separate shutdown + create events might be useful for some
> circumstances but it would also be good be good to distinguish the case of a
> true reboot. Maybe it could be a flag to the shutdown / create events since
> it seems possible that some of the work will be the same.
Yes that would be ideal.
> Cool. None of this discussion precludes the usefulness of the patches you've
> proposed, I'm just wondering if a slightly more generic version would be a
> good idea.
> I've currently only thought about this at a high level - am not so familiar
> with the post-Xenstore tools.
I'm not familiar with xenstore at all yet.
> I'd say it'll be more complex in the implementation than your current patch,
> but it might scale better with different kind of event configurations:
> associating scripts directly with Xenstore changes gives us the ability to
> monitor all kinds of stuff, almost "for free".
That seems reasonable. The only downside is that I think I'd
be unable to implement it. I will try to find some time over the
next day or two to see how this stuff works and how easy it is
to "watch" with a daemon.
> Possibly we'd need a bit of "syntactic sugar" to make specifying the Xenstore
> watches more palatable for people who don't like to know about the internals
> of the management plane ;-) If necessary, some kind of "shorthand" for
> specifying common events might work well.
> As far as I know, stuff like paused / unpaused status is not available in
> Xenstore. The obvious solution would be to create a Xenstore node allowing
> Xend to announce when it has paused / unpaused domains to Xenstore watchers
> who might be interested. This could easily generalise to other tools-level
> events as well.
Right. I guess that could be added later, once the xenstore watching
side was working for the events which were available immediately.
> Another feature which I had in mind when thinking about this was that of
> domain users requesting they have a previous backup of the filesystem
> restored. By simply writing to a Xenstore node from within their domain,
> they could request that the management plane restore a backup of their
> filesystem from a particular date and then reboot them with it. That would
> be super cool ;-)
That would. I didn't realise that the xenstore would be accessible
from within the domU - but I guess that just emphasizes the fact that
I'm hazy on how that stuff works.
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