On Sat, Dec 06, 2014 at 04:38:52PM +1100, Tony Breeds wrote: > Hi All, > In the most recent team meeting we briefly discussed:  where the > console.log grows indefinitely, eventually causing guest stalls. I mentioned > that I was working on a spec to fix this issue. > > My original plan was fairly similar to  In that we'd switch libvirt/qemu > to > using a unix domain socket and write a simple helper to read from that socket > and write to disk. That helper would close and reopen the on disk file upon > receiving a HUP (so logrotate just works). Life would be good. and we could > all move on. > > However I was encouraged to investigate fixing this in qemu, such that qemu > could process the HUP and make life better for all. This is certainly doable > and I'm happy to do this work. I've floated the idea past qemu-devel and > they seem okay with the idea. My main concern is in lag and supporting > qemu/libvirt that can't handle this option.
As mentioned in my reply on qemu-devel, I think the right long term solution for this is to fix it in libvirt. We have a general security goal to remove QEMU's ability to open any files whatsoever, instead having it receive all host resources as pre-opened file descriptors from libvirt. So what we anticipate is a new libvirt daemon for processing logs, virtlogd. Anywhere where QEMU currently gets a file to log to (<serial> devices, and its stdout/stderr), it would instead be given a FD that's connected to virtlogd. virtlogd would simply write the data out to file & would be able to close & re-open files to integrate with logrotate. > For the sake of discussion I'll lay out my best guess right now on fixing > this > in qemu. > > qemu 2.2.0 /should/ release this year the ETA is 2014-12-09 so the fix I'm > proposing would be available in qemu 2.3.0 which I think will be available in > June/July 2015. So we'd be into 'L' development before this fix is available > and possibly 'M' before the community distros (Fedora and Ubuntu) include > and almost certainly longer for Enterprise distros. Along with the qemu > development I expect there to be some libvirt development as well but right > now > I don't think that's critical to the feature or this discussion. > > So if that timeline is approximately correct: > > - Can we wait this long to fix the bug? As opposed to having it squashed in > Kilo. > - What do we do in nova for the next ~12 months while know there isn't a qemu > to fix this? > - Then once there is a qemu that fixes the issue, do we just say 'thou must > use > qemu 2.3.0' or would nova still need to support old and new qemu's ? FWIW, by comparison libvirt is on a monthly release schedule, so a fix done in libvirt has potential to be available sooner, though obviously there's bigger dev work to be done in libvirt for this. Regards, Daniel -- |: http://berrange.com -o- http://www.flickr.com/photos/dberrange/ :| |: http://libvirt.org -o- http://virt-manager.org :| |: http://autobuild.org -o- http://search.cpan.org/~danberr/ :| |: http://entangle-photo.org -o- http://live.gnome.org/gtk-vnc :| _______________________________________________ OpenStack-dev mailing list OpenStackemail@example.com http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack-dev