Hi Encho, it sounds strange that the standby JobManager tries to recover a submitted job graph. This should only happen if it has been granted leadership. Thus, it seems as if the standby JobManager thinks that it is also the leader. Could you maybe share the logs of the two JobManagers/ClusterEntrypoints with us?
Running only a single JobManager/ClusterEntrypoint in HA mode via a Kubernetes Deployment should do the trick and there is nothing wrong with it. Cheers, Till On Wed, Aug 29, 2018 at 11:05 AM Encho Mishinev <encho.mishi...@gmail.com> wrote: > Hello, > > Since two job managers don't seem to be working for me I was thinking of > just using a single job manager in Kubernetes in HA mode with a deployment > ensuring its restart whenever it fails. Is this approach viable? The > High-Availability page mentions that you use only one job manager in an > YARN cluster but does not specify such option for Kubernetes. Is there > anything that can go wrong with this approach? > > Thanks > > On Wed, Aug 29, 2018 at 11:10 AM Encho Mishinev <encho.mishi...@gmail.com> > wrote: > >> Hi, >> >> Unfortunately the thing I described does indeed happen every time. As >> mentioned in the first email, I am running on Kubernetes so certain things >> could be different compared to just a standalone cluster. >> >> Any ideas for workarounds are welcome, as this problem basically prevents >> me from using HA. >> >> Thanks, >> Encho >> >> On Wed, Aug 29, 2018 at 5:15 AM vino yang <yanghua1...@gmail.com> wrote: >> >>> Hi Encho, >>> >>> From your description, I feel that there are extra bugs. >>> >>> About your description: >>> >>> *- Start both job managers* >>> *- Start a batch job in JobManager 1 and let it finish* >>> *The jobgraphs in both Zookeeper and HDFS remained.* >>> >>> Is it necessarily happening every time? >>> >>> In the Standalone cluster, the problems we encountered were sporadic. >>> >>> Thanks, vino. >>> >>> Encho Mishinev <encho.mishi...@gmail.com> 于2018年8月28日周二 下午8:07写道： >>> >>>> Hello Till, >>>> >>>> I spend a few more hours testing and looking at the logs and it seems >>>> like there's a more general problem here. While the two job managers are >>>> active neither of them can properly delete jobgraphs. The above problem I >>>> described comes from the fact that Kubernetes gets JobManager 1 quickly >>>> after I manually kill it, so when I stop the job on JobManager 2 both are >>>> alive. >>>> >>>> I did a very simple test: >>>> >>>> - Start both job managers >>>> - Start a batch job in JobManager 1 and let it finish >>>> The jobgraphs in both Zookeeper and HDFS remained. >>>> >>>> On the other hand if we do: >>>> >>>> - Start only JobManager 1 (again in HA mode) >>>> - Start a batch job and let it finish >>>> The jobgraphs in both Zookeeper and HDFS are deleted fine. >>>> >>>> It seems like the standby manager still leaves some kind of lock on the >>>> jobgraphs. Do you think that's possible? Have you seen a similar problem? >>>> The only logs that appear on the standby manager while waiting are of >>>> the type: >>>> >>>> 2018-08-28 11:54:10,789 INFO >>>> org.apache.flink.runtime.jobmanager.ZooKeeperSubmittedJobGraphStore - >>>> Recovered SubmittedJobGraph(9e0a109b57511930c95d3b54574a66e3, null). >>>> >>>> Note that this log appears on the standby jobmanager immediately when a >>>> new job is submitted to the active jobmanager. >>>> Also note that the blobs and checkpoints are cleared fine. The problem >>>> is only for jobgraphs both in ZooKeeper and HDFS. >>>> >>>> Trying to access the UI of the standby manager redirects to the active >>>> one, so it is not a problem of them not knowing who the leader is. Do you >>>> have any ideas? >>>> >>>> Thanks a lot, >>>> Encho >>>> >>>> On Tue, Aug 28, 2018 at 10:27 AM Till Rohrmann <trohrm...@apache.org> >>>> wrote: >>>> >>>>> Hi Encho, >>>>> >>>>> thanks a lot for reporting this issue. The problem arises whenever the >>>>> old leader maintains the connection to ZooKeeper. If this is the case, >>>>> then >>>>> ephemeral nodes which we create to protect against faulty delete >>>>> operations >>>>> are not removed and consequently the new leader is not able to delete the >>>>> persisted job graph. So one thing to check is whether the old JM still has >>>>> an open connection to ZooKeeper. The next thing to check is the session >>>>> timeout of your ZooKeeper cluster. If you stop the job within the session >>>>> timeout, then it is also not guaranteed that ZooKeeper has detected that >>>>> the ephemeral nodes of the old JM must be deleted. In order to understand >>>>> this better it would be helpful if you could tell us the timing of the >>>>> different actions. >>>>> >>>>> Cheers, >>>>> Till >>>>> >>>>> On Tue, Aug 28, 2018 at 8:17 AM vino yang <yanghua1...@gmail.com> >>>>> wrote: >>>>> >>>>>> Hi Encho, >>>>>> >>>>>> A temporary solution can be used to determine if it has been cleaned >>>>>> up by monitoring the specific JobID under Zookeeper's "/jobgraph". >>>>>> Another solution, modify the source code, rudely modify the cleanup >>>>>> mode to the synchronous form, but the flink operation Zookeeper's path >>>>>> needs to obtain the corresponding lock, so it is dangerous to do so, and >>>>>> it >>>>>> is not recommended. >>>>>> I think maybe this problem can be solved in the next version. It >>>>>> depends on Till. >>>>>> >>>>>> Thanks, vino. >>>>>> >>>>>> Encho Mishinev <encho.mishi...@gmail.com> 于2018年8月28日周二 下午1:17写道： >>>>>> >>>>>>> Thank you very much for the info! Will keep track of the progress. >>>>>>> >>>>>>> In the meantime is there any viable workaround? It seems like HA >>>>>>> doesn't really work due to this bug. >>>>>>> >>>>>>> On Tue, Aug 28, 2018 at 4:52 AM vino yang <yanghua1...@gmail.com> >>>>>>> wrote: >>>>>>> >>>>>>>> About some implementation mechanisms. >>>>>>>> Flink uses Zookeeper to store JobGraph (Job's description >>>>>>>> information and metadata) as a basis for Job recovery. >>>>>>>> However, previous implementations may cause this information to not >>>>>>>> be properly cleaned up because it is asynchronously deleted by a >>>>>>>> background >>>>>>>> thread. >>>>>>>> >>>>>>>> Thanks, vino. >>>>>>>> >>>>>>>> vino yang <yanghua1...@gmail.com> 于2018年8月28日周二 上午9:49写道： >>>>>>>> >>>>>>>>> Hi Encho, >>>>>>>>> >>>>>>>>> This is a problem already known to the Flink community, you can >>>>>>>>> track its progress through FLINK-10011[1], and currently Till is >>>>>>>>> fixing >>>>>>>>> this issue. >>>>>>>>> >>>>>>>>> [1]: https://issues.apache.org/jira/browse/FLINK-10011 >>>>>>>>> >>>>>>>>> Thanks, vino. >>>>>>>>> >>>>>>>>> Encho Mishinev <encho.mishi...@gmail.com> 于2018年8月27日周一 下午10:13写道： >>>>>>>>> >>>>>>>>>> I am running Flink 1.5.3 with two job managers and two task >>>>>>>>>> managers in Kubernetes along with HDFS and Zookeeper in >>>>>>>>>> high-availability >>>>>>>>>> mode. >>>>>>>>>> >>>>>>>>>> My problem occurs after the following actions: >>>>>>>>>> - Upload a .jar file to jobmanager-1 >>>>>>>>>> - Run a streaming job from the jar on jobmanager-1 >>>>>>>>>> - Wait for 1 or 2 checkpoints to succeed >>>>>>>>>> - Kill pod of jobmanager-1 >>>>>>>>>> After a short delay, jobmanager-2 takes leadership and correctly >>>>>>>>>> restores the job and continues it >>>>>>>>>> - Stop job from jobmanager-2 >>>>>>>>>> >>>>>>>>>> At this point all seems well, but the problem is that >>>>>>>>>> jobmanager-2 does not clean up anything that was left from >>>>>>>>>> jobmanager-1. >>>>>>>>>> This means that both in HDFS and in Zookeeper remain job graphs, >>>>>>>>>> which >>>>>>>>>> later on obstruct any work of both managers as after any reset they >>>>>>>>>> unsuccessfully try to restore a non-existent job and fail over and >>>>>>>>>> over >>>>>>>>>> again. >>>>>>>>>> >>>>>>>>>> I am quite certain that jobmanager-2 does not know about any of >>>>>>>>>> jobmanager-1’s files since the Zookeeper logs reveal that it tries to >>>>>>>>>> duplicate job folders: >>>>>>>>>> >>>>>>>>>> 2018-08-27 13:11:00,038 [myid:] - INFO [ProcessThread(sid:0 >>>>>>>>>> cport:2181)::PrepRequestProcessor@648] - Got user-level >>>>>>>>>> KeeperException when processing sessionid:0x1657aa15e480033 >>>>>>>>>> type:create >>>>>>>>>> cxid:0x46 zxid:0x1ab txntype:-1 reqpath:n/a Error >>>>>>>>>> Path:/flink/default/jobgraphs/83bfa359ca59ce1d4635e18e16651e15/bbb259fd-7826-4950-bc7c-c2be23346c77 >>>>>>>>>> Error:KeeperErrorCode = NodeExists for >>>>>>>>>> /flink/default/jobgraphs/83bfa359ca59ce1d4635e18e16651e15/bbb259fd-7826-4950-bc7c-c2be23346c77 >>>>>>>>>> >>>>>>>>>> 2018-08-27 13:11:02,296 [myid:] - INFO [ProcessThread(sid:0 >>>>>>>>>> cport:2181)::PrepRequestProcessor@648] - Got user-level >>>>>>>>>> KeeperException when processing sessionid:0x1657aa15e480033 >>>>>>>>>> type:create >>>>>>>>>> cxid:0x5c zxid:0x1ac txntype:-1 reqpath:n/a Error >>>>>>>>>> Path:/flink/default/checkpoint-counter/83bfa359ca59ce1d4635e18e16651e15 >>>>>>>>>> Error:KeeperErrorCode = NodeExists for >>>>>>>>>> /flink/default/checkpoint-counter/83bfa359ca59ce1d4635e18e16651e15 >>>>>>>>>> >>>>>>>>>> Also jobmanager-2 attempts to delete the jobgraphs folder in >>>>>>>>>> Zookeeper when the job is stopped, but fails since there are >>>>>>>>>> leftover files >>>>>>>>>> in it from jobmanager-1: >>>>>>>>>> >>>>>>>>>> 2018-08-27 13:12:13,406 [myid:] - INFO [ProcessThread(sid:0 >>>>>>>>>> cport:2181)::PrepRequestProcessor@648] - Got user-level >>>>>>>>>> KeeperException when processing sessionid:0x1657aa15e480033 >>>>>>>>>> type:delete >>>>>>>>>> cxid:0xa8 zxid:0x1bd txntype:-1 reqpath:n/a Error >>>>>>>>>> Path:/flink/default/jobgraphs/83bfa359ca59ce1d4635e18e16651e15 >>>>>>>>>> Error:KeeperErrorCode = Directory not empty for >>>>>>>>>> /flink/default/jobgraphs/83bfa359ca59ce1d4635e18e16651e15 >>>>>>>>>> >>>>>>>>>> I’ve noticed that when restoring the job, it seems like >>>>>>>>>> jobmanager-2 does not get anything more than jobID, while it perhaps >>>>>>>>>> needs >>>>>>>>>> some metadata? Here is the log that seems suspicious to me: >>>>>>>>>> >>>>>>>>>> 2018-08-27 13:09:18,113 INFO >>>>>>>>>> org.apache.flink.runtime.jobmanager.ZooKeeperSubmittedJobGraphStore >>>>>>>>>> - >>>>>>>>>> Recovered SubmittedJobGraph(83bfa359ca59ce1d4635e18e16651e15, null). >>>>>>>>>> >>>>>>>>>> All other logs seem fine in jobmanager-2, it doesn’t seem to be >>>>>>>>>> aware that it’s overwriting anything or not deleting properly. >>>>>>>>>> >>>>>>>>>> My question is - what is the intended way for the job managers to >>>>>>>>>> correctly exchange metadata in HA mode and why is it not working for >>>>>>>>>> me? >>>>>>>>>> >>>>>>>>>> Thanks in advance! >>>>>>>>> >>>>>>>>>
