[openstack-dev] [Neutron][Infra] Post processing of gate hooks on job timeouts

Clark Boylan cboylan at sapwetik.org
Mon Apr 11 17:56:16 UTC 2016


On Mon, Apr 11, 2016, at 10:52 AM, Jakub Libosvar wrote:
> 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].

My suggestion would be to stop writing these log files to /tmp and
instead write them to the log dir where they will be automagically
compressed and collected.

> 
> > 
> > [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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> 
> 
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