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On 04/11/2016 06:41 PM, Clark Boylan wrote:
> On Mon, Apr 11, 2016, at 03:07 AM, Jakub Libosvar wrote:
>> Hi,
>>
>> recently we hit an issue in Neutron with tests getting stuck [1]. As a
>> side effect we discovered logs are not collected properly which makes it
>> hard to find the root cause. The reason of missing logs is that we send
>> SIGKILL to whatever gate hook is running when we hit the global timeout
>> per gate job [2]. This gives no time to running process to perform any
>> post-processing. In post_gate_hook function in Neutron, we collect logs
>> from /tmp directory, compress them and move them to /opt/stack/logs to
>> make them exposed.
>>
>> I have in mind two solutions to which I'd like to get feedback before
>> sending patches.
>>
>> 1) In Neutron, we execute tests in post_gate_hook (dunno why). But even
>> if we would have moved test execution into gate_hook and tests get stuck
>> then the post_gate_hook won't be triggered [3]. So the solution I
>> propose here is to terminate gate_hook N minutes before global timeout
>> and still execute post_gate_hook (with timeout) as post-processing
>> routine.
>>
>> 2) Second proposal is to let timeout wrapped commands know they are
>> about to be killed. We can send let's say SIGTERM instead of SIGKILL and
>> after certain amount of time, send SIGKILL. Example: We send SIGTERM 3
>> minutes before global timeout, letting these 3 minutes to 'command' to
>> handle the SIGTERM signal.
>>
>>  timeout -s 15 -k 3 $((REMAINING_TIME-3))m bash -c "command"
>>
>> With the 2nd approach we can trap the signal that kills running test
>> suite and collects logs with same functions we currently have.
>>
>>
>> I would personally go with second option but I want to hear if anybody
>> has a better idea about post processing in gate jobs or if there is
>> already a tool we can use to collect logs.
>>
>> Thanks,
>> Kuba
> 
> Devstack gate already does a "soft" timeout [0] then proceeds to cleanup
> (part of which is collecting logs) [1], then Jenkins does the "hard"
> timeout [2]. Why aren't we collecting the required log files as part of
> the existing cleanup?
This existing cleanup doesn't support hooks. Neutron tests produce a lot
of logs by default stored in /tmp/dsvm-<job_name> so we need to compress
and move them to /opt/stack/logs in order to get them collected by [1].

> 
> [0]
> https://git.openstack.org/cgit/openstack-infra/devstack-gate/tree/devstack-vm-gate-wrap.sh#n569
> [1]
> https://git.openstack.org/cgit/openstack-infra/devstack-gate/tree/devstack-vm-gate-wrap.sh#n594
> [2]
> https://git.openstack.org/cgit/openstack-infra/project-config/tree/jenkins/jobs/devstack-gate.yaml#n325
> 
> Clark
> 
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