Hi Eleanore, >From my experience, collecting the Flink metrics to prometheus via metrics collector is a more ideal way. It is also easier to configure the alert. Maybe you could use "fullRestarts" or "numRestarts" to monitor the job restarting. More metrics could be find here[2].
[1]. https://ci.apache.org/projects/flink/flink-docs-master/monitoring/metrics.html#prometheus-orgapacheflinkmetricsprometheusprometheusreporter [2]. https://ci.apache.org/projects/flink/flink-docs-master/monitoring/metrics.html#availability Best, Yang Eleanore Jin <eleanore....@gmail.com> 于2020年8月5日周三 下午11:52写道： > Hi Yang and Till, > > Thanks a lot for the help! I have the similar question as Till mentioned, > if we do not fail Flink pods when the restart strategy is exhausted, it > might be hard to monitor such failures. Today I get alerts if the k8s pods > are restarted or in crash loop, but if this will no longer be the case, how > can we deal with the monitoring? In production, I have hundreds of small > flink jobs running (2-8 TM pods) doing stateless processing, it is really > hard for us to expose ingress for each JM rest endpoint to periodically > query the job status for each flink job. > > Thanks a lot! > Eleanore > > On Wed, Aug 5, 2020 at 4:56 AM Till Rohrmann <trohrm...@apache.org> wrote: > >> You are right Yang Wang. >> >> Thanks for creating this issue. >> >> Cheers, >> Till >> >> On Wed, Aug 5, 2020 at 1:33 PM Yang Wang <danrtsey...@gmail.com> wrote: >> >>> Actually, the application status shows in YARN web UI is not determined >>> by the jobmanager process exit code. >>> Instead, we use "resourceManagerClient.unregisterApplicationMaster" to >>> control the final status of YARN application. >>> So although jobmanager exit with zero code, it still could show failed >>> status in YARN web UI. >>> >>> I have created a ticket to track this improvement[1]. >>> >>> [1]. https://issues.apache.org/jira/browse/FLINK-18828 >>> >>> >>> Best, >>> Yang >>> >>> >>> Till Rohrmann <trohrm...@apache.org> 于2020年8月5日周三 下午3:56写道： >>> >>>> Yes for the other deployments it is not a problem. A reason why people >>>> preferred non-zero exit codes in case of FAILED jobs is that this is easier >>>> to monitor than having to take a look at the actual job result. Moreover, >>>> in the YARN web UI the application shows as failed if I am not mistaken. >>>> However, from a framework's perspective, a FAILED job does not mean that >>>> Flink has failed and, hence, the return code could still be 0 in my >>>> opinion. >>>> >>>> Cheers, >>>> Till >>>> >>>> On Wed, Aug 5, 2020 at 9:30 AM Yang Wang <danrtsey...@gmail.com> wrote: >>>> >>>>> Hi Eleanore, >>>>> >>>>> Yes, I suggest to use Job to replace Deployment. It could be used >>>>> to run jobmanager one time and finish after a successful/failed >>>>> completion. >>>>> >>>>> However, using Job still could not solve your problem completely. Just >>>>> as Till said, When a job exhausts the restart strategy, the jobmanager >>>>> pod will terminate with non-zero exit code. It will cause the K8s >>>>> restarting it again. Even though we could set the resartPolicy and >>>>> backoffLimit, >>>>> this is not a clean and correct way to go. We should terminate the >>>>> jobmanager process with zero exit code in such situation. >>>>> >>>>> @Till Rohrmann <trohrm...@apache.org> I just have one concern. Is it >>>>> a special case for K8s deployment? For standalone/Yarn/Mesos, it seems >>>>> that >>>>> terminating with >>>>> non-zero exit code is harmless. >>>>> >>>>> >>>>> Best, >>>>> Yang >>>>> >>>>> Eleanore Jin <eleanore....@gmail.com> 于2020年8月4日周二 下午11:54写道： >>>>> >>>>>> Hi Yang & Till, >>>>>> >>>>>> Thanks for your prompt reply! >>>>>> >>>>>> Yang, regarding your question, I am actually not using k8s job, as I >>>>>> put my app.jar and its dependencies under flink's lib directory. I have 1 >>>>>> k8s deployment for job manager, and 1 k8s deployment for task manager, >>>>>> and >>>>>> 1 k8s service for job manager. >>>>>> >>>>>> As you mentioned above, if flink job is marked as failed, it will >>>>>> cause the job manager pod to be restarted. Which is not the ideal >>>>>> behavior. >>>>>> >>>>>> Do you suggest that I should change the deployment strategy from >>>>>> using k8s deployment to k8s job? In case the flink program exit with >>>>>> non-zero code (e.g. exhausted number of configured restart), pod can be >>>>>> marked as complete hence not restarting the job again? >>>>>> >>>>>> Thanks a lot! >>>>>> Eleanore >>>>>> >>>>>> On Tue, Aug 4, 2020 at 2:49 AM Yang Wang <danrtsey...@gmail.com> >>>>>> wrote: >>>>>> >>>>>>> @Till Rohrmann <trohrm...@apache.org> In native mode, when a Flink >>>>>>> application terminates with FAILED state, all the resources will be >>>>>>> cleaned >>>>>>> up. >>>>>>> >>>>>>> However, in standalone mode, I agree with you that we need to >>>>>>> rethink the exit code of Flink. When a job exhausts the restart >>>>>>> strategy, we should terminate the pod and do not restart again. >>>>>>> After googling, it seems that we could not specify the restartPolicy >>>>>>> based on exit code[1]. So maybe we need to return a zero exit code >>>>>>> to avoid restarting by K8s. >>>>>>> >>>>>>> [1]. >>>>>>> https://stackoverflow.com/questions/48797297/is-it-possible-to-define-restartpolicy-based-on-container-exit-code >>>>>>> >>>>>>> Best, >>>>>>> Yang >>>>>>> >>>>>>> Till Rohrmann <trohrm...@apache.org> 于2020年8月4日周二 下午3:48写道： >>>>>>> >>>>>>>> @Yang Wang <danrtsey...@gmail.com> I believe that we should >>>>>>>> rethink the exit codes of Flink. In general you want K8s to restart a >>>>>>>> failed Flink process. Hence, an application which terminates in state >>>>>>>> FAILED should not return a non-zero exit code because it is a valid >>>>>>>> termination state. >>>>>>>> >>>>>>>> Cheers, >>>>>>>> Till >>>>>>>> >>>>>>>> On Tue, Aug 4, 2020 at 8:55 AM Yang Wang <danrtsey...@gmail.com> >>>>>>>> wrote: >>>>>>>> >>>>>>>>> Hi Eleanore, >>>>>>>>> >>>>>>>>> I think you are using K8s resource "Job" to deploy the jobmanager. >>>>>>>>> Please set .spec.template.spec.restartPolicy = "Never" and >>>>>>>>> spec.backoffLimit = 0. >>>>>>>>> Refer here[1] for more information. >>>>>>>>> >>>>>>>>> Then, when the jobmanager failed because of any reason, the K8s >>>>>>>>> job will be marked failed. And K8s will not restart the job again. >>>>>>>>> >>>>>>>>> [1]. >>>>>>>>> https://kubernetes.io/docs/concepts/workloads/controllers/job/#job-termination-and-cleanup >>>>>>>>> >>>>>>>>> >>>>>>>>> Best, >>>>>>>>> Yang >>>>>>>>> >>>>>>>>> Eleanore Jin <eleanore....@gmail.com> 于2020年8月4日周二 上午12:05写道： >>>>>>>>> >>>>>>>>>> Hi Till, >>>>>>>>>> >>>>>>>>>> Thanks for the reply! >>>>>>>>>> >>>>>>>>>> I manually deploy as per-job mode [1] and I am using Flink 1.8.2. >>>>>>>>>> Specifically, I build a custom docker image, which I copied the app >>>>>>>>>> jar >>>>>>>>>> (not uber jar) and all its dependencies under /flink/lib. >>>>>>>>>> >>>>>>>>>> So my question is more like, in this case, if the job is marked >>>>>>>>>> as FAILED, which causes k8s to restart the pod, this seems not help >>>>>>>>>> at all, >>>>>>>>>> what are the suggestions for such scenario? >>>>>>>>>> >>>>>>>>>> Thanks a lot! >>>>>>>>>> Eleanore >>>>>>>>>> >>>>>>>>>> [1] >>>>>>>>>> https://ci.apache.org/projects/flink/flink-docs-release-1.8/ops/deployment/kubernetes.html#flink-job-cluster-on-kubernetes >>>>>>>>>> >>>>>>>>>> On Mon, Aug 3, 2020 at 2:13 AM Till Rohrmann < >>>>>>>>>> trohrm...@apache.org> wrote: >>>>>>>>>> >>>>>>>>>>> Hi Eleanore, >>>>>>>>>>> >>>>>>>>>>> how are you deploying Flink exactly? Are you using the >>>>>>>>>>> application mode with native K8s support to deploy a cluster [1] or >>>>>>>>>>> are you >>>>>>>>>>> manually deploying a per-job mode [2]? >>>>>>>>>>> >>>>>>>>>>> I believe the problem might be that we terminate the Flink >>>>>>>>>>> process with a non-zero exit code if the job reaches the >>>>>>>>>>> ApplicationStatus.FAILED [3]. >>>>>>>>>>> >>>>>>>>>>> cc Yang Wang have you observed a similar behavior when running >>>>>>>>>>> Flink in per-job mode on K8s? >>>>>>>>>>> >>>>>>>>>>> [1] >>>>>>>>>>> https://ci.apache.org/projects/flink/flink-docs-release-1.11/ops/deployment/native_kubernetes.html#flink-kubernetes-application >>>>>>>>>>> [2] >>>>>>>>>>> https://ci.apache.org/projects/flink/flink-docs-release-1.11/ops/deployment/kubernetes.html#job-cluster-resource-definitions >>>>>>>>>>> [3] >>>>>>>>>>> https://github.com/apache/flink/blob/master/flink-runtime/src/main/java/org/apache/flink/runtime/clusterframework/ApplicationStatus.java#L32 >>>>>>>>>>> >>>>>>>>>>> On Fri, Jul 31, 2020 at 6:26 PM Eleanore Jin < >>>>>>>>>>> eleanore....@gmail.com> wrote: >>>>>>>>>>> >>>>>>>>>>>> Hi Experts, >>>>>>>>>>>> >>>>>>>>>>>> I have a flink cluster (per job mode) running on kubernetes. >>>>>>>>>>>> The job is configured with restart strategy >>>>>>>>>>>> >>>>>>>>>>>> restart-strategy.fixed-delay.attempts: >>>>>>>>>>>> 3restart-strategy.fixed-delay.delay: 10 s >>>>>>>>>>>> >>>>>>>>>>>> >>>>>>>>>>>> So after 3 times retry, the job will be marked as FAILED, hence >>>>>>>>>>>> the pods are not running. However, kubernetes will then restart >>>>>>>>>>>> the job >>>>>>>>>>>> again as the available replicas do not match the desired one. >>>>>>>>>>>> >>>>>>>>>>>> I wonder what are the suggestions for such a scenario? How >>>>>>>>>>>> should I configure the flink job running on k8s? >>>>>>>>>>>> >>>>>>>>>>>> Thanks a lot! >>>>>>>>>>>> Eleanore >>>>>>>>>>>> >>>>>>>>>>>
