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On Tue, Oct 30, 2018 at 11:36 AM Ben Nemec <openstack at nemebean.com> wrote:
>
> Tagging with tripleo since my suggestion below is specific to that project.
>
> On 10/30/18 11:03 AM, Clark Boylan wrote:
> > Hello everyone,
> >
> > A little while back I sent email explaining how the gate queues work and how fixing bugs helps us test and merge more code. All of this still is still true and we should keep pushing to improve our testing to avoid gate resets.
> >
> > Last week we migrated Zuul and Nodepool to a new Zookeeper cluster. In the process of doing this we had to restart Zuul which brought in a new logging feature that exposes node resource usage by jobs. Using this data I've been able to generate some report information on where our node demand is going. This change [0] produces this report [1].
> >
> > As with optimizing software we want to identify which changes will have the biggest impact and to be able to measure whether or not changes have had an impact once we have made them. Hopefully this information is a start at doing that. Currently we can only look back to the point Zuul was restarted, but we have a thirty day log rotation for this service and should be able to look at a month's worth of data going forward.
> >
> > Looking at the data you might notice that Tripleo is using many more node resources than our other projects. They are aware of this and have a plan [2] to reduce their resource consumption. We'll likely be using this report generator to check progress of this plan over time.
>
> I know at one point we had discussed reducing the concurrency of the
> tripleo gate to help with this. Since tripleo is still using >50% of the
> resources it seems like maybe we should revisit that, at least for the
> short-term until the more major changes can be made? Looking through the
> merge history for tripleo projects I don't see a lot of cases (any, in
> fact) where more than a dozen patches made it through anyway*, so I
> suspect it wouldn't have a significant impact on gate throughput, but it
> would free up quite a few nodes for other uses.
>

It's the failures in gate and resets.  At this point I think it would
be a good idea to turn down the concurrency of the tripleo queue in
the gate if possible. As of late it's been timeouts but we've been
unable to track down why it's timing out specifically.  I personally
have a feeling it's the container download times since we do not have
a local registry available and are only able to leverage the mirrors
for some levels of caching. Unfortunately we don't get the best
information about this out of docker (or the mirrors) and it's really
hard to determine what exactly makes things run a bit slower.

I've asked about the status of moving the scenarios off of multinode
to standalone which would half the number of systems being run for
these jobs. It's currently next on the list of things to tackle after
we get a single fedora28 job up and running.

Thanks,
-Alex

> *: I have no actual stats to back that up, I'm just looking through the
> IRC backlog for merge bot messages. If such stats do exist somewhere we
> should look at them instead. :-)
>
> >
> > Also related to the long queue backlogs is this proposal [3] to change how Zuul prioritizes resource allocations to try to be more fair.
> >
> > [0] https://review.openstack.org/#/c/613674/
> > [1] http://paste.openstack.org/show/733644/
> > [2] http://lists.openstack.org/pipermail/openstack-dev/2018-October/135396.html
> > [3] http://lists.zuul-ci.org/pipermail/zuul-discuss/2018-October/000575.html
> >
> > If you find any of this interesting and would like to help feel free to reach out to myself or the infra team.
> >
> > Thank you,
> > Clark
> >
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