Re: [Libvir] Restarting of libvirt_qemud daemon
On Fri, Mar 09, 2007 at 10:47:18AM +0000, Richard W.M. Jones wrote:
Daniel P. Berrange wrote:
>Thinking about later RPM upgrades I think we need to think about whether it
>will be possible to restart the libvirt_qemud while guests & networks are
>running. There's a couple of issues:
>
> - We do waitpid() to cleanup qemu & dnsmasq processes when we stop domains
> & networks, or to detect when they crash. For the former, we could may
> they daemons to avoid waitpid() cleanup, but we'd still need waitpid to
> be able to detect shutdowns. There is also the issue of enumerating
> running instances.
Maybe I'm missing something big here, but how would libvirt_qemud regain
connections to the running qemu monitor ptys?
That's one of the challenges to be addressed :-) Fortunately the monitor
is set to be exposed via /dev/pty/XXX, so if the restarted client can
find out the path to the PTY, then it can re-open it. Maybe we just need
to record a state file somewhere containing a PID & PTY path.
Dan.
--
|=- Red Hat, Engineering, Emerging Technologies, Boston. +1 978 392 2496 -=|
|=- Perl modules: http://search.cpan.org/~danberr/ -=|
|=- Projects: http://freshmeat.net/~danielpb/ -=|
|=- GnuPG: 7D3B9505 F3C9 553F A1DA 4AC2 5648 23C1 B3DF F742 7D3B 9505 -=|