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On 11/10/2015 1:10 PM, Matt Riedemann wrote:
>
>
> On 11/10/2015 12:51 PM, Armando M. wrote:
>>
>>
>> On 10 November 2015 at 10:33, Matt Riedemann <mriedem at linux.vnet.ibm.com
>> <mailto:mriedem at linux.vnet.ibm.com>> wrote:
>>
>>     Let me qualify by saying I'm not a Neutron person.
>>
>>     We know that gate-tempest-dsvm-neutron-full is failing hard as of
>>     the last 24 hours [1].
>>
>>     An error that's been showing up in tempest runs with neutron a lot
>> is:
>>
>>     "AssertionError: 0 == 0 : No IPv4 addresses found in: []"
>>
>>     So checking logstash [2] it's hitting a lot. It's only recent
>>     because that failure message is new to Tempest in the last day or
>>     so, but it has a lot of hits, so whatever it is, it's failing a lot.
>>
>>     So the next step is usually digging into service logs looking for
>>     errors. I check the q-svc logs first. Not many errors but a
>>     bazillion warnings for things not found (networks and devices). [3]
>>
>>     For example:
>>
>>     2015-11-10 17:13:02.542 WARNING neutron.plugins.ml2.rpc
>>     [req-15a73753-1512-4689-9404-9658a0cd0c09 None None] Device
>>     aaa525be-14eb-44a5-beb0-ed722896be93 requested by agent
>>     ovs-agent-devstack-trusty-rax-iad-5785199 not found in database
>>
>>     2015-11-10 17:14:17.754 WARNING neutron.api.rpc.handlers.dhcp_rpc
>>     [req-3d7e9848-6151-4780-907f-43f11a2a8545 None None] Network
>>     b07ad9b2-e63e-4459-879d-3721074704e5 could not be found, it might
>>     have been deleted concurrently.
>>
>>     Are several hundred of these warnings useful to an operator trying
>>     to debug a problem? The point of the CI gate testing is to try and
>>     simulate a production cloud environment. When something goes wrong,
>>     you check the logs. With the amount of warning/error level logging
>>     that is in the neutron logs, finding a real problem is like looking
>>     for a needle in a haystack. Since everything is async, 404s are
>>     expected when racing to delete a resource and they should be handled
>>     gracefully.
>>
>>     Anyway, the server log isn't useful so I go digging in the agent
>>     logs and stacktraces there are aplenty. [4]
>>
>>     Particularly this:
>>
>>     "Exception: Port tapcea51630-e1 is not ready, resync needed"
>>
>>     That's due to a new change landing in the last 24 hours [5]. But the
>>     trace shows up over 16K times since it landed [6].
>>
>>     Checking the code, it's basically a loop processing events and when
>>     it hits an event it can't handle, it punts (breaking the loop so you
>>     don't process the other events after it - which is a bug), and the
>>     code that eventually handles it is just catching all Exception and
>>     tracing them out assuming they are really bad.
>>
>>     At this point, as a non-neutron person, i.e. not well versed in the
>>     operations of neutron or how to debug it in great detail, I assume
>>     something is bad here but I don't really know - and the logs are so
>>     full of noise that I can't distinguish real failures.
>>
>>     I don't mean to pick on this particular change, but it's a good
>>     example of a recent thing.
>>
>>     I'd like to know if this is all known issue or WIP type stuff. I've
>>     complained about excessively noisey neutron logs in channel before
>>     and I'm usually told that they are either necessary (for whatever
>>     reason) or that rather than complain about the verbosity, I should
>>     fix the race that is causing it - which is not likely to happen
>>     since I don't have the async rpc happy nature of everything in
>>     neutron in my head to debug it (I doubt many do).
>>
>>
>> I am not sure that's a fair statement: we usually pinpoint that just
>> lowering log levels is not really solving the underlying issue
>> (whichever it may be), and that comment really should apply to any
>> project, not just Neutron. That said, we had examples where we took your
>> input and drove the right fix ourselves.
>>
>> We have a 'logging' tag for Neutron bugs that we use to identify these
>> type of cleanups. We'd need your attention to details to alert us of
>> issues like these; we'll take care of the right fixes. Currently, the
>> queue is pretty dry. If you can top it up, that'll be great. Going off
>> on a log cleanup rampage doesn't seem like the best course of action;
>> I'd rather knock issues one by one as they come, like the one you just
>> mentioned.
>>
>> [1] https://bugs.launchpad.net/neutron/+bugs?field.tag=logging
>
> Tagged:
>
> https://bugs.launchpad.net/nova/+bug/1514935
>
> Although it must not be an official tag since it didn't auto-complete
> for me, that should be fixed.

Crap, nevermind that, my bad - I had created the bug against nova (force 
of habit) rather than neutron. Confirmed that 'logging' is a neutron tag 
in LP.

>
>>
>>
>>     Anyway, this is a plea for sanity in the logs. There are logging
>>     guidelines for openstack [7]. Let's please abide by them. Let's keep
>>     operators in mind when we're looking at logs and be proactive about
>>     making them useful (which includes more granular error handling and
>>     less global try/except Exception: LOG.exception constructs).
>>
>> Your point is duly noted. We have documented this, and we are being more
>> meticulous during reviews.
>>
>>
>>     [1] http://tinyurl.com/ne3ex4v
>>     [2]
>>
>> http://logstash.openstack.org/#dashboard/file/logstash.json?query=message:%5C%22AssertionError:%200%20==%200%20:%20No%20IPv4%20addresses%20found%20in:%20%5B%5D%5C%22%20AND%20tags:%5C%22console%5C%22
>>
>>     [3]
>>
>> http://logs.openstack.org/85/239885/2/gate/gate-tempest-dsvm-neutron-full/602d864/logs/screen-q-svc.txt.gz?level=TRACE
>>
>>     [4]
>>
>> http://logs.openstack.org/85/239885/2/gate/gate-tempest-dsvm-neutron-full/602d864/logs/screen-q-agt.txt.gz?level=TRACE
>>
>>     [5] https://review.openstack.org/#/c/164880/
>>     [6]
>>
>> http://logstash.openstack.org/#dashboard/file/logstash.json?query=message:%5C%22Exception:%20Port%5C%22%20AND%20message:%5C%22is%20not%20ready,%20resync%20needed%5C%22%20AND%20tags:%5C%22screen-q-agt.txt%5C%22
>>
>>     [7]
>>
>> http://specs.openstack.org/openstack/openstack-specs/specs/log-guidelines.html
>>
>>
>>     --
>>
>>     Thanks,
>>
>>     Matt Riedemann
>>
>>
>>
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>

-- 

Thanks,

Matt Riedemann