[openstack-dev] [nova] Fixing the console.log grows forever bug.

Tim Bell Tim.Bell at cern.ch
Sun Dec 7 08:47:28 UTC 2014

> -----Original Message-----
> From: Tony Breeds [mailto:tony at bakeyournoodle.com]
> Sent: 06 December 2014 06:39
> To: openstack-dev at lists.openstack.org
> Subject: [openstack-dev] [nova] Fixing the console.log grows forever bug.
> 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[3] 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.

Would the nova view console be able to see the older versions also ? Ideally, we'd also improve on the current situation where the console contents are limited to the current file which causes problems around hard reboot operations such as watchdog restarts. Thus, if qemu is logrotating the log files, the view console OpenStack operations would ideally be able to count all the rotated files as part of the console output.

> 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[4] 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)[5] 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 ?

Can we just say that the console for qemu 2.2 would remain as currently and for the new functionality, you need qemu 2.3 ?

> [1] https://bugs.launchpad.net/nova/+bug/832507
> [2] https://review.openstack.org/#/c/80865/
> [3] For some value of happy ;P
> [4] From http://wiki.qemu.org/Planning/2.2 [5] Debian and Gentoo are a little
> harder to quantify in this scenario but no
>     less important.
> Yours Tony.
> PS: If any of you have a secret laundry list of things qemu should do to make
>     life easier for nova.  Put them on a wiki page so we can discuss them.
> PPS: If this is going to be a thing we do (write features and fixes in qemu)
>      we're going to need a consistent plan on how we cope with that.

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