On Mon, Feb 12, 2018 at 12:44:52PM +0100, Martin Kletzander wrote:
On Thu, Feb 01, 2018 at 09:58:17AM -0500, John Ferlan wrote:
>
>
> On 02/01/2018 09:04 AM, Michal Privoznik wrote:
> > In 2074ef6cd4a2 and c56cdf259 (and friends) we've added two
> > attributes to virtio NICs: rx_queue_size and tx_queue_size.
> > However, sysadmins might want to set these on per-host basis but
> > don't necessarily have an access to domain XML (e.g. because they
> > are generated by some other app). So let's expose them under
Define "sysadmins" here. If there's a management app running that
covers some hosts, then the app is the sysadmin. Who will be setting
these in the conf file? Some person? Manually? I don't think so. My
bet is that it will be the same mgmt app that generates the XML. Or the
same person who deploys the app, but still manually. If that app is
unable to have a default, then why should libvirt be?
IIUC, this feature came in as a request to solve a limitation that
exists in OpenStack nova not having support for setting this feature
for guest XML.
IMHO the right fix for that request is to address the feature gap
in Nova, not add this to libvirt to workaround fact that Nova has
not supported this yet.
> > qemu.conf (the settings from domain XML still take
precedence as
> > they are more specific ones).
> >
> > Signed-off-by: Michal Privoznik <mprivozn(a)redhat.com>
> > ---
> >
> > diff to v1:
> > - Reworded docs and config file comment
> > - Simplified logic in qemuBuildNicDevStr a bit
> > - Make the values require qemu with corresponding capabilities
> >
> > docs/formatdomain.html.in | 14 ++++++++--
> > src/qemu/libvirtd_qemu.aug | 4 +++
> > src/qemu/qemu.conf | 6 +++++
> > src/qemu/qemu_command.c | 55
+++++++++++++++++++++++++++-----------
> > src/qemu/qemu_command.h | 3 ++-
> > src/qemu/qemu_conf.c | 4 +++
> > src/qemu/qemu_conf.h | 3 +++
> > src/qemu/qemu_hotplug.c | 2 +-
> > src/qemu/test_libvirtd_qemu.aug.in | 2 ++
> > 9 files changed, 74 insertions(+), 19 deletions(-)
> >
>
> Reviewed-by: John Ferlan <jferlan(a)redhat.com>
>
Sorry I missed this earlier, I'm going through my e-mail backlog kinda
too late. But I don't think this should be released. Or anything
similar. If we make this change, then where do we draw the line for
setting defaults in qemu.conf? Will we eventually have defaults for
first interface, memory size or even whole XML that get's parsed before
the user-supplied one? I know it's too late to NACK this, but please
consider reverting it before next release.
Agreed, I'd like to see this reverted too as it is a bad precedent and
there's no obvious reason why Nova can't simply support this feature
itself. Even if nova doesn't want to make it user configurable, it
could be set as a default in the nova.conf file, or driven via information
it acquires from Neutron.
Regards,
Daniel
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