[openstack-dev] [elastic-recheck] Thoughts on next steps

Joe Gordon joe.gordon0 at gmail.com
Tue Jan 7 00:04:56 UTC 2014

Overall this looks really good, and very spot on.

On Thu, Jan 2, 2014 at 6:29 PM, Sean Dague <sean at dague.net> wrote:

> A lot of elastic recheck this fall has been based on the ad hoc needs of
> the moment, in between diving down into the race bugs that were uncovered
> by it. This week away from it all helped provide a little perspective on
> what I think we need to do to call it *done* (i.e. something akin to a 1.0
> even though we are CDing it).
> Here is my current thinking on the next major things that should happen.
> Opinions welcomed.
> (These are roughly in implementation order based on urgency)
> = Split of web UI =
> The elastic recheck page is becoming a mismash of what was needed at the
> time. I think what we really have emerging is:
>  * Overall Gate Health
>  * Known (to ER) Bugs
>  * Unknown (to ER) Bugs - more below
> I think the landing page should be Know Bugs, as that's where we want both
> bug hunters to go to prioritize things, as well as where people looking for
> known bugs should start.
> I think the overall Gate Health graphs should move to the zuul status
> page. Possibly as part of the collection of graphs at the bottom.
> We should have a secondary page (maybe column?) of the un-fingerprinted
> recheck bugs, largely to use as candidates for fingerprinting. This will
> let us eventually take over /recheck.
I think it would be cool to collect the list of unclassified failures (not
by recheck bug), so we can see how many (and what percentage) need to be
classified. This isn't gate health but more of e-r health or something like

> = Data Analysis / Graphs =
> I spent a bunch of time playing with pandas over break (
> http://dague.net/2013/12/30/ipython-notebook-experiments/), it's kind of
> awesome. It also made me rethink our approach to handling the data.
> I think the rolling average approach we were taking is more precise than
> accurate. As these are statistical events they really need error bars.
> Because when we have a quiet night, and 1 job fails at 6am in the morning,
> the 100% failure rate it reflects in grenade needs to be quantified that it
> was 1 of 1, not 50 of 50.

> So my feeling is we should move away from the point graphs we have, and
> present these as weekly and daily failure rates (with graphs and error
> bars). And slice those per job. My suggestion is that we do the actual
> visualization with matplotlib because it's super easy to output that from
> pandas data sets.

The one thing that the current graph does, that weekly and daily failure
rates don't show, is a sudden spike in one of the lines.  If you stare at
the current graphs for long enough and can read through the noise, you can
see when the gate collectively crashes or if just the neutron related gates
start failing. So I think one more graph is needed.

> Basically we'll be mining Elastic Search -> Pandas TimeSeries ->
> transforms and analysis -> output tables and graphs. This is different
> enough from our current jquery graphing that I want to get ACKs before
> doing a bunch of work here and finding out people don't like it in reviews.
> Also in this process upgrade the metadata that we provide for each of
> those bugs so it's a little more clear what you are looking at.

For example?

> = Take over of /recheck =
> There is still a bunch of useful data coming in on "recheck bug ####" data
> which hasn't been curated into ER queries. I think the right thing to do is
> treat these as a work queue of bugs we should be building patterns out of
> (or completely invalidating). I've got a preliminary gerrit bulk query
> piece of code that does this, which would remove the need of the daemon the
> way that's currently happening. The gerrit queries are a little long right
> now, but I think if we are only doing this on hourly cron, the additional
> load will be negligible.
> This would get us into a single view, which I think would be more
> informative than the one we currently have.

treating /recheck as a work queue sounds great, but this needs a bit more
fleshing out I think.

I imagine the workflow as something like this:

* State 1: Path author files bug saying 'gate broke, I didn't do it and
don't know why it broke'.
* State 2: Someone investigates the bug and determines if bug is valid and
if its a duplicate or not. root cause still isn't known.
* State 3: Someone writes a fingerprint for this bug and commits it to

Assuming we agree on this general workflow, it would be nice if /recheck
distinguished between bugs in states 1 and 2, and there is no need to list
bugs in state 3 as e-r bot will automatically tell a developer when he hits

> = Categorize all the jobs =
> We need a bit of refactoring to let us comment on all the jobs (not just
> tempest ones). Basically we assumed pep8 and docs don't fail in the gate at
> the beginning. Turns out they do, and are good indicators of infra /
> external factor bugs. They are a part of the story so we should put them in.

Don't forget grenade

> = Multi Line Fingerprints =
> We've definitely found bugs where we never had a really satisfying single
> line match, but we had some great matches if we could do multi line.
> We could do that in ER, however it will mean giving up logstash as our UI,
> because those queries can't be done in logstash. So in order to do this
> we'll really need to implement some tools - cli minimum, which will let us
> easily test a bug. A custom web UI might be in order as well, though that's
> going to be it's own chunk of work, that we'll need more volunteers for.
> This would put us in a place where we should have all the infrastructure
> to track 90% of the race conditions, and talk about them in certainty as
> 1%, 5%, 0.1% bugs.

Horrah. multi line matches are two separate elasticSearch queries, where
you match build_uuids.  So to get the set of all hits of a multi line
fingerprint you find the intersection between line_1 and line_2 where the
key is build_uuid

>         -Sean
> --
> Sean Dague
> Samsung Research America
> sean at dague.net / sean.dague at samsung.com
> http://dague.net
> _______________________________________________
> OpenStack-dev mailing list
> OpenStack-dev at lists.openstack.org
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