samza-dev mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From Jagadish Venkatraman <jagadish1...@gmail.com>
Subject Re: Old style "low level" Tasks with alternative deployment model(s)
Date Tue, 20 Mar 2018 18:36:27 GMT
Hi Tom,

>> Happy to put something together this weekend as well.

Great, can't wait!!

>> What format would that be best in?

You can open a PR in markdown format.

Here's an example PR for Kinesis:
https://github.com/apache/samza/pull/384/files/
Here's how it looks and renders in our web-page:
https://samza.apache.org/learn/documentation/0.14/aws/kinesis.html

Best,
Jagdish

On Tue, Mar 20, 2018 at 11:24 AM, Tom Davis <tom@recursivedream.com> wrote:

> What format would that be best in? Happy to put something together this
> weekend as well.
>
> Jagadish Venkatraman <jagadish1989@gmail.com> writes:
>
> Hi Thunder,
>>
>> Thank you for the PR. Really nice work!
>>
>> Since, you have a working implementation on K8s, would you be willing to
>> contribute a short tutorial / a post on this? We'll be sure to feature it
>> in the official Samza web-site at http://samza.apache.org/.
>>
>> It'd be a great addition to the Samza community to have a section on K8s
>> integration! There have been multiple prior asks on this, and your
>> learnings would be super-helpful.
>>
>> Best,
>> Jagdish
>>
>>
>>
>> On Tue, Mar 20, 2018 at 10:46 AM, Prateek Maheshwari <
>> prateekmi2@gmail.com>
>> wrote:
>>
>> Glad you were able to figure it out, that was very confusing. Thanks for
>>> the fix too.
>>>
>>> - Prateek
>>>
>>> On Mon, Mar 19, 2018 at 9:58 PM, Thunder Stumpges <tstumpges@ntent.com>
>>> wrote:
>>>
>>> And that last issue was mine. My setting override was not picked up and
>>>> it was using GroupByContainerCount instead.
>>>> -Thanks,
>>>> Thunder
>>>>
>>>>
>>>> -----Original Message-----
>>>> From: Thunder Stumpges
>>>> Sent: Monday, March 19, 2018 20:58
>>>> To: dev@samza.apache.org
>>>> Cc: Jagadish Venkatraman <jagadish1989@gmail.com>;
>>>> tom@recursivedream.com;
>>>> Yipan@linkedin.com; Yi Pan <nickpan47@gmail.com>
>>>> Subject: RE: Old style "low level" Tasks with alternative deployment
>>>> model(s)
>>>>
>>>> Well I figured it out. My specific issue was due to a simple dependency
>>>> problem where I had gotten an older version of the Jackson-mapper
>>>> library.
>>>> However the code was throwing NoSuchMethodError (an Error instead of
>>>> Exception) and being silently dropped. I created a pull request to
>>>> handle
>>>> any Throwable in ScheduleAfterDebounceTime.
>>>> https://github.com/apache/samza/pull/450
>>>>
>>>> I'm now running into an issue with the generation of the JobModel and
>>>> the
>>>> ProcessorId. The ZkJobCoordinator has a ProcessorId that is a Guid, but
>>>> when GroupByContainerIds class (my TaskNameGrouper) creates the
>>>> ContainerModels, it is using the ContainerId (a numeric value,
>>>> 0,1,2,etc)
>>>> as the ProcessorId (~ line 105). This results in the JobModel that is
>>>> generated and published immediately causing the processor to quit with
>>>> this
>>>> message:
>>>>
>>>> INFO  o.apache.samza.zk.ZkJobCoordinator - New JobModel does not
>>>> contain
>>>> pid=38c637bf-9c2b-4856-afc4-5b1562711cfb. Stopping this processor.
>>>>
>>>> I was assuming I should be using GroupByContainerIds as my
>>>> TaskNameGrouper. I don't see any other promising implementations. Am I
>>>> just
>>>> missing something?
>>>>
>>>> Thanks,
>>>> Thunder
>>>>
>>>> JobModel
>>>> {
>>>>   "config" : {
>>>>   ...
>>>>   },
>>>>   "containers" : {
>>>>     "0" : {
>>>>       "tasks" : {
>>>>         "Partition 0" : {
>>>>           "task-name" : "Partition 0",
>>>>           "system-stream-partitions" : [ {
>>>>             "system" : "kafka",
>>>>             "partition" : 0,
>>>>             "stream" : "test_topic1"
>>>>           }, {
>>>>             "system" : "kafka",
>>>>             "partition" : 0,
>>>>             "stream" : "test_topic2"
>>>>           } ],
>>>>           "changelog-partition" : 0
>>>>         },
>>>>         "Partition 1" : {
>>>>           "task-name" : "Partition 1",
>>>>           "system-stream-partitions" : [ {
>>>>             "system" : "kafka",
>>>>             "partition" : 1,
>>>>             "stream" : "test_topic1"
>>>>           }, {
>>>>             "system" : "kafka",
>>>>             "partition" : 1,
>>>>             "stream" : "test_topic2"
>>>>           } ],
>>>>           "changelog-partition" : 1
>>>>         }
>>>>       },
>>>>       "container-id" : 0,
>>>>       "processor-id" : "0"
>>>>     }
>>>>   },
>>>>   "max-change-log-stream-partitions" : 2,
>>>>   "all-container-locality" : {
>>>>     "0" : null
>>>>   }
>>>> }
>>>>
>>>> -----Original Message-----
>>>> From: Thunder Stumpges [mailto:tstumpges@ntent.com]
>>>> Sent: Friday, March 16, 2018 18:21
>>>> To: dev@samza.apache.org
>>>> Cc: Jagadish Venkatraman <jagadish1989@gmail.com>;
>>>> tom@recursivedream.com;
>>>> Yipan@linkedin.com; Yi Pan <nickpan47@gmail.com>
>>>> Subject: RE: Old style "low level" Tasks with alternative deployment
>>>> model(s)
>>>>
>>>> Attached. I don't see any threads actually running this code which is
>>>> odd.
>>>>
>>>> There's my main thread that's waiting for the whole thing to finish, the
>>>> "debounce-thread-0" (which logged the other surrounding messages below)
>>>> has
>>>> this:
>>>>
>>>> "debounce-thread-0" #18 daemon prio=5 os_prio=0 tid=0x00007fa0fd719800
>>>> nid=0x21 waiting on condition [0x00007fa0d0d45000]
>>>>    java.lang.Thread.State: WAITING (parking)
>>>>         at sun.misc.Unsafe.park(Native Method)
>>>>         - parking to wait for  <0x00000006f166e350> (a
>>>> java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject)
>>>>         at java.util.concurrent.locks.LockSupport.park(LockSupport.java
>>>> :175)
>>>>         at java.util.concurrent.locks.AbstractQueuedSynchronizer$Condit
>>>> ionObject.await(AbstractQueuedSynchronizer.java:2039)
>>>>         at java.util.concurrent.ScheduledThreadPoolExecutor$DelayedWork
>>>> Queue.take(ScheduledThreadPoolExecutor.java:1081)
>>>>         at java.util.concurrent.ScheduledThreadPoolExecutor$DelayedWork
>>>> Queue.take(ScheduledThreadPoolExecutor.java:809)
>>>>         at java.util.concurrent.ThreadPoolExecutor.getTask(ThreadPoolEx
>>>> ecutor.java:1067)
>>>>         at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPool
>>>> Executor.java:1127)
>>>>         at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoo
>>>> lExecutor.java:617)
>>>>
>>>>         at java.lang.Thread.run(Thread.java:745)
>>>>
>>>>    Locked ownable synchronizers:
>>>>         - None
>>>>
>>>> Thanks for having a look.
>>>> Thunder
>>>>
>>>>
>>>> -----Original Message-----
>>>> From: Prateek Maheshwari [mailto:prateekmi2@gmail.com]
>>>> Sent: Friday, March 16, 2018 17:02
>>>> To: dev@samza.apache.org
>>>> Cc: Jagadish Venkatraman <jagadish1989@gmail.com>;
>>>> tom@recursivedream.com;
>>>> Yipan@linkedin.com; Yi Pan <nickpan47@gmail.com>
>>>> Subject: Re: Old style "low level" Tasks with alternative deployment
>>>> model(s)
>>>>
>>>> Hi Thunder,
>>>>
>>>> Can you please take and attach a thread dump with this?
>>>>
>>>> Thanks,
>>>> Prateek
>>>>
>>>> On Fri, Mar 16, 2018 at 4:47 PM, Thunder Stumpges <tstumpges@ntent.com>
>>>> wrote:
>>>>
>>>> > It appears it IS hung while serializing the JobModel... very strange!
>>>> > I added some debug statements around the calls:
>>>> >
>>>> >       LOG.debug("Getting object mapper to serialize job model");  //
>>>> > this IS printed
>>>> >       ObjectMapper mmapper = SamzaObjectMapper.getObjectMapper();
>>>> >       LOG.debug("Serializing job model"); // this IS printed
>>>> >       String jobModelStr = mmapper.writerWithDefaultPrettyPrinter
>>>> > ().writeValueAsString(jobModel);
>>>> >       LOG.info("jobModelAsString=" + jobModelStr); // this is NOT
>>>> printed!
>>>> >
>>>> > Another thing I noticed is that "getObjectMapper" actually creates the
>>>> > object mapper twice!
>>>> >
>>>> > 2018-03-16 23:09:24 logback 24985 [debounce-thread-0] DEBUG
>>>> > org.apache.samza.zk.ZkUtils - Getting object mapper to serialize job
>>>> > model
>>>> > 2018-03-16 23:09:24 logback 24994 [debounce-thread-0] DEBUG
>>>> > o.a.s.s.model.SamzaObjectMapper
>>>> > - Creating new object mapper and simple module
>>>> > 2018-03-16 23:09:24 logback 25178 [debounce-thread-0] DEBUG
>>>> > o.a.s.s.model.SamzaObjectMapper
>>>> > - Adding SerDes and mixins
>>>> > 2018-03-16 23:09:24 logback 25183 [debounce-thread-0] DEBUG
>>>> > o.a.s.s.model.SamzaObjectMapper
>>>> > - Adding custom ContainerModel deserializer
>>>> > 2018-03-16 23:09:24 logback 25184 [debounce-thread-0] DEBUG
>>>> > o.a.s.s.model.SamzaObjectMapper
>>>> > - Setting up naming strategy and registering module
>>>> > 2018-03-16 23:09:24 logback 25187 [debounce-thread-0] DEBUG
>>>> > o.a.s.s.model.SamzaObjectMapper
>>>> > - Done!
>>>> > 2018-03-16 23:09:24 logback 25187 [debounce-thread-0] DEBUG
>>>> > o.a.s.s.model.SamzaObjectMapper
>>>> > - Creating new object mapper and simple module
>>>> > 2018-03-16 23:09:24 logback 25187 [debounce-thread-0] DEBUG
>>>> > o.a.s.s.model.SamzaObjectMapper
>>>> > - Adding SerDes  and mixins
>>>> > 2018-03-16 23:09:24 logback 25187 [debounce-thread-0] DEBUG
>>>> > o.a.s.s.model.SamzaObjectMapper
>>>> > - Adding custom ContainerModel deserializer
>>>> > 2018-03-16 23:09:24 logback 25187 [debounce-thread-0] DEBUG
>>>> > o.a.s.s.model.SamzaObjectMapper
>>>> > - Setting up naming strategy and registering module
>>>> > 2018-03-16 23:09:24 logback 25187 [debounce-thread-0] DEBUG
>>>> > o.a.s.s.model.SamzaObjectMapper
>>>> > - Done!
>>>> > 2018-03-16 23:09:24 logback 25187 [debounce-thread-0] DEBUG
>>>> > org.apache.samza.zk.ZkUtils - Serializing job model
>>>> >
>>>> > Could this ObjectMapper be a singleton? I see there is a private
>>>> > static instance, but getObjectMapper creates a new one every time...
>>>> >
>>>> > Anyway, then it takes off to serialize the job model and never comes
>>>> > back...
>>>> >
>>>> > Hoping someone has some idea here... the implementation for this
>>>> > mostly comes from Jackson-mapper-asl, and I have the version that is
>>>> > linked in the
>>>> > 0.14.0 tag:
>>>> > |    |    |    +--- org.codehaus.jackson:jackson-mapper-asl:1.9.13
>>>> > |    |    |    |    \--- org.codehaus.jackson:jackson-core-asl:1.9.13
>>>> >
>>>> > Thanks!
>>>> > Thunder
>>>> >
>>>> > -----Original Message-----
>>>> > From: Thunder Stumpges [mailto:tstumpges@ntent.com]
>>>> > Sent: Friday, March 16, 2018 15:29
>>>> > To: dev@samza.apache.org; Jagadish Venkatraman
>>>> > <jagadish1989@gmail.com>
>>>> > Cc: tom@recursivedream.com; Yipan@linkedin.com; Yi Pan <
>>>> > nickpan47@gmail.com>
>>>> > Subject: RE: Old style "low level" Tasks with alternative deployment
>>>> > model(s)
>>>> >
>>>> > So, my investigation starts at StreamProcessor.java.  Line 294 in
>>>> > method
>>>> > onNewJobModel() logs an INFO message that it's starting a container.
>>>> > This message never appears.
>>>> >
>>>> > I see that ZkJobCoordinator calls onNewJobModel from its
>>>> > onNewJobModelConfirmed method which also logs an info message stating
>>>> > "version X of the job model got confirmed". I never see this message
>>>> > either, so I go up the chain some more.
>>>> >
>>>> > I DO see:
>>>> >
>>>> > 2018-03-16 21:43:58 logback 20498
>>>> > [ZkClient-EventThread-13-10.0.127.114:2181]
>>>> > INFO  o.apache.samza.zk.ZkJobCoordinator -
>>>> > ZkJobCoordinator::onBecomeLeader
>>>> > - I became the leader!
>>>> > And
>>>> > 2018-03-16 21:44:18 logback 40712 [debounce-thread-0] INFO
>>>> > o.apache.samza.zk.ZkJobCoordinator -
>>>> > pid=91e07d20-ae33-4156-a5f3-534a95642133Generated
>>>> > new Job Model. Version = 1
>>>> >
>>>> > Which led me to method onDoProcessorChange line 210. I see that line,
>>>> > but not the line below " Published new Job Model. Version =" so
>>>> > something in here is not completing:
>>>> >
>>>> >     LOG.info("pid=" + processorId + "Generated new Job Model. Version
>>>> =
>>>> "
>>>> > + nextJMVersion);
>>>> >
>>>> >     // Publish the new job model
>>>> >     zkUtils.publishJobModel(nextJMVersion, jobModel);
>>>> >
>>>> >     // Start the barrier for the job model update
>>>> >     barrier.create(nextJMVersion, currentProcessorIds);
>>>> >
>>>> >     // Notify all processors about the new JobModel by updating
>>>> > JobModel Version number
>>>> >     zkUtils.publishJobModelVersion(currentJMVersion, nextJMVersion);
>>>> >
>>>> >     LOG.info("pid=" + processorId + "Published new Job Model. Version
>>>> =
>>>> "
>>>> > + nextJMVersion);
>>>> >
>>>> > As I mentioned, after the line "Generated new Job Model. Version = 1"
>>>> > I just get repeated zk ping responses.. no more application logging.
>>>> >
>>>> > The very next thing that's run is zkUtils.publishJobModel() which only
>>>> > has two lines before another log statement (which I don't see):
>>>> >
>>>> >   public void publishJobModel(String jobModelVersion, JobModel
>>>> jobModel) {
>>>> >     try {
>>>> >       ObjectMapper mmapper = SamzaObjectMapper.getObjectMapper();
>>>> >       String jobModelStr = mmapper.writerWithDefaultPrettyPrinter
>>>> > ().writeValueAsString(jobModel);
>>>> >       LOG.info("jobModelAsString=" + jobModelStr);
>>>> >       ...
>>>> >
>>>> > Could it really be getting hung up on one of these two lines? (seems
>>>> > like it must be, but I don't see anything there that seems like it
>>>> > would just hang). I'll keep troubleshooting, maybe add some more debug
>>>> > logging and try again.
>>>> >
>>>> > Thanks for any guidance you all might have.
>>>> > -Thunder
>>>> >
>>>> >
>>>> > -----Original Message-----
>>>> > From: Thunder Stumpges [mailto:tstumpges@ntent.com]
>>>> > Sent: Friday, March 16, 2018 14:43
>>>> > To: dev@samza.apache.org; Jagadish Venkatraman
>>>> > <jagadish1989@gmail.com>
>>>> > Cc: tom@recursivedream.com; Yipan@linkedin.com; Yi Pan <
>>>> > nickpan47@gmail.com>
>>>> > Subject: RE: Old style "low level" Tasks with alternative deployment
>>>> > model(s)
>>>> >
>>>> > Well I have my stand-alone application in docker and running in
>>>> > kubernetes. I think something isn't wired up all the way though,
>>>> > because my task never actually gets invoked. I see no errors, however
>>>> > I'm not getting the usual startup logs (checking existing offsets,
>>>> > "entering run loop"...) My logs look like this:
>>>> >
>>>> > 2018-03-16 21:05:55 logback 50797 [debounce-thread-0] INFO
>>>> > kafka.utils.VerifiableProperties
>>>> > - Verifying properties
>>>> > 2018-03-16 21:05:55 logback 50797 [debounce-thread-0] INFO
>>>> > kafka.utils.VerifiableProperties
>>>> > - Property client.id is overridden to samza_admin-test_stream_task-1
>>>> > 2018-03-16 21:05:55 logback 50798 [debounce-thread-0] INFO
>>>> > kafka.utils.VerifiableProperties
>>>> > - Property metadata.broker.list is overridden to
>>>> > test-kafka-kafka.test-svc:9092
>>>> > 2018-03-16 21:05:55 logback 50798 [debounce-thread-0] INFO
>>>> > kafka.utils.VerifiableProperties
>>>> > - Property request.timeout.ms is overridden to 30000
>>>> > 2018-03-16 21:05:55 logback 50799 [debounce-thread-0] INFO
>>>> > kafka.client.ClientUtils$ - Fetching metadata from broker
>>>> > BrokerEndPoint(0,test-kafka-kafka.test-svc,9092) with correlation id
>>>> 0
>>>> > for 1 topic(s) Set(dev_k8s.samza.test.topic)
>>>> > 2018-03-16 21:05:55 logback 50800 [debounce-thread-0] DEBUG
>>>> > kafka.network.BlockingChannel - Created socket with SO_TIMEOUT = 30000
>>>> > (requested 30000), SO_RCVBUF = 179680 (requested -1), SO_SNDBUF =
>>>> > 102400 (requested 102400), connectTimeoutMs = 30000.
>>>> > 2018-03-16 21:05:55 logback 50800 [debounce-thread-0] INFO
>>>> > kafka.producer.SyncProducer - Connected to
>>>> > test-kafka-kafka.test-svc:9092 for producing
>>>> > 2018-03-16 21:05:55 logback 50804 [debounce-thread-0] INFO
>>>> > kafka.producer.SyncProducer - Disconnecting from
>>>> > test-kafka-kafka.test-svc:9092
>>>> > 2018-03-16 21:05:55 logback 50804 [debounce-thread-0] DEBUG
>>>> > kafka.client.ClientUtils$ - Successfully fetched metadata for 1
>>>> > topic(s)
>>>> > Set(dev_k8s.samza.test.topic)
>>>> > 2018-03-16 21:05:55 logback 50813 [debounce-thread-0] INFO
>>>> > o.a.s.coordinator.JobModelManager$ - SystemStreamPartitionGrouper
>>>> > org.apache.samza.container.grouper.stream.GroupByPartition@1a7158cc
>>>> > has grouped the SystemStreamPartitions into 10 tasks with the
>>>> > following
>>>> > taskNames: [Partition 1, Partition 0, Partition 3, Partition 2,
>>>> > Partition 5, Partition 4, Partition 7, Partition 6, Partition 9,
>>>> > Partition 8]
>>>> > 2018-03-16 21:05:55 logback 50818 [debounce-thread-0] INFO
>>>> > o.a.s.coordinator.JobModelManager$ - New task Partition 0 is being
>>>> > assigned changelog partition 0.
>>>> > 2018-03-16 21:05:55 logback 50819 [debounce-thread-0] INFO
>>>> > o.a.s.coordinator.JobModelManager$ - New task Partition 1 is being
>>>> > assigned changelog partition 1.
>>>> > 2018-03-16 21:05:55 logback 50820 [debounce-thread-0] INFO
>>>> > o.a.s.coordinator.JobModelManager$ - New task Partition 2 is being
>>>> > assigned changelog partition 2.
>>>> > 2018-03-16 21:05:55 logback 50820 [debounce-thread-0] INFO
>>>> > o.a.s.coordinator.JobModelManager$ - New task Partition 3 is being
>>>> > assigned changelog partition 3.
>>>> > 2018-03-16 21:05:55 logback 50820 [debounce-thread-0] INFO
>>>> > o.a.s.coordinator.JobModelManager$ - New task Partition 4 is being
>>>> > assigned changelog partition 4.
>>>> > 2018-03-16 21:05:55 logback 50820 [debounce-thread-0] INFO
>>>> > o.a.s.coordinator.JobModelManager$ - New task Partition 5 is being
>>>> > assigned changelog partition 5.
>>>> > 2018-03-16 21:05:55 logback 50820 [debounce-thread-0] INFO
>>>> > o.a.s.coordinator.JobModelManager$ - New task Partition 6 is being
>>>> > assigned changelog partition 6.
>>>> > 2018-03-16 21:05:55 logback 50820 [debounce-thread-0] INFO
>>>> > o.a.s.coordinator.JobModelManager$ - New task Partition 7 is being
>>>> > assigned changelog partition 7.
>>>> > 2018-03-16 21:05:55 logback 50820 [debounce-thread-0] INFO
>>>> > o.a.s.coordinator.JobModelManager$ - New task Partition 8 is being
>>>> > assigned changelog partition 8.
>>>> > 2018-03-16 21:05:55 logback 50820 [debounce-thread-0] INFO
>>>> > o.a.s.coordinator.JobModelManager$ - New task Partition 9 is being
>>>> > assigned changelog partition 9.
>>>> > 2018-03-16 21:05:55 logback 50838 [main-SendThread(10.0.127.114:2181
>>>> )]
>>>> > DEBUG org.apache.zookeeper.ClientCnxn - Reading reply
>>>> > sessionid:0x1622c8b5fc01ac7, packet:: clientPath:null serverPath:null
>>>> > finished:false header:: 23,4  replyHeader:: 23,14024,0  request::
>>>> > '/app-test_stream_task-1/dev_test_stream_task-1-coordinationData/
>>>> > JobModelGeneration/jobModelVersion,T  response::
>>>> > ,s{13878,13878,1521234010089,1521234010089,0,0,0,0,0,0,13878}
>>>> > 2018-03-16 21:05:55 logback 50838 [debounce-thread-0] INFO
>>>> > o.apache.samza.zk.ZkJobCoordinator -
>>>> > pid=a14a0434-a238-4ff6-935b-c78d906fe80dGenerated
>>>> > new Job Model. Version = 1
>>>> > 2018-03-16 21:06:05 logback 60848 [main-SendThread(10.0.127.114:2181
>>>> )]
>>>> > DEBUG org.apache.zookeeper.ClientCnxn - Got ping response for
>>>> sessionid:
>>>> > 0x1622c8b5fc01ac7 after 2ms
>>>> > 2018-03-16 21:06:15 logback 70856 [main-SendThread(10.0.127.114:2181
>>>> )]
>>>> > DEBUG org.apache.zookeeper.ClientCnxn - Got ping response for
>>>> sessionid:
>>>> > 0x1622c8b5fc01ac7 after 1ms
>>>> > 2018-03-16 21:06:25 logback 80865 [main-SendThread(10.0.127.114:2181
>>>> )]
>>>> > DEBUG org.apache.zookeeper.ClientCnxn - Got ping response for
>>>> sessionid:
>>>> > 0x1622c8b5fc01ac7 after 2ms ...
>>>> >
>>>> > The zk ping responses continue every 10 seconds, but no other activity
>>>> > or messages occur.
>>>> > It looks like it gets as far as confirming the JobModel and grouping
>>>> > the partitions, but nothing actually starts up.
>>>> >
>>>> > Any ideas?
>>>> > Thanks in advance!
>>>> > Thunder
>>>> >
>>>> >
>>>> > -----Original Message-----
>>>> > From: Thunder Stumpges [mailto:tstumpges@ntent.com]
>>>> > Sent: Thursday, March 15, 2018 16:35
>>>> > To: Jagadish Venkatraman <jagadish1989@gmail.com>
>>>> > Cc: dev@samza.apache.org; tom@recursivedream.com; Yipan@linkedin.com;
>>>> > Yi Pan <nickpan47@gmail.com>
>>>> > Subject: RE: Old style "low level" Tasks with alternative deployment
>>>> > model(s)
>>>> >
>>>> > Thanks a lot for the info. I have something basically working at this
>>>> > point! I have not integrated it with Docker nor Kubernetes yet, but it
>>>> > does run from my local machine.
>>>> >
>>>> > I have determined that LocalApplicationRunner does NOT do config
>>>> > rewriting. I had to write my own little “StandAloneApplicationRunner”
>>>> > that handles the “main” entrypoint. It does command parsing using
>>>> > CommandLine, load config from ConfigFactory, and perform rewriting
>>>> > before creating the new instance of LocalApplicationRunner. This is
>>>> > all my StandAloneApplicationRunner contains:
>>>> >
>>>> >
>>>> > object StandAloneSamzaRunner extends App with LazyLogging {
>>>> >
>>>> >   // parse command line args just like JobRunner.
>>>> >   val cmdline = new ApplicationRunnerCommandLine
>>>> >   val options = cmdline.parser.parse(args: _*)
>>>> >   val config = cmdline.loadConfig(options)
>>>> >
>>>> >   val runner = new LocalApplicationRunner(Util.rewriteConfig(config))
>>>> >   runner.runTask()
>>>> >   runner.waitForFinish()
>>>> > }
>>>> >
>>>> > The only config settings I needed to make to use this runner were
>>>> > (easily configured due to our central Consul config system and our
>>>> rewriter) :
>>>> >
>>>> > # use the ZK based job coordinator
>>>> > job.coordinator.factory=org.apache.samza.zk.ZkJobCoordinatorFactory
>>>> > # need to use GroupByContainerIds instead of GroupByContainerCount
>>>> > task.name.grouper.factory=org.apache.samza.container.grouper.task.
>>>> > GroupByContainerIdsFactory
>>>> > # ZKJC config
>>>> > job.coordinator.zk.connect=<our_zk_connection>
>>>> >
>>>> > I did run into one potential problem; as you see above, I have started
>>>> > the task using runTask() and then to prevent my main method from
>>>> > returning, I have called waitForFinish(). The first time I ran it, the
>>>> > job itself failed because I had forgotten to override the task
>>>> > grouper, and container count was pulled from our staging environment.
>>>> > There are some failures logged and it appears the JobCoordinator
>>>> > fails, but it never returns from waitForFinish. Stack trace and
>>>> continuation of log is below:
>>>> >
>>>> > 2018-03-15 22:34:32 logback 77786 [debounce-thread-0] ERROR
>>>> > o.a.s.zk.ScheduleAfterDebounceTime
>>>> > - Execution of action: OnProcessorChange failed.
>>>> > java.lang.IllegalArgumentException: Your container count (4) is
>>>> larger
>>>> > than your task count (2). Can't have containers with nothing to do, so
>>>> > aborting.
>>>> >        at org.apache.samza.container.gro
>>>> uper.task.GroupByContainerCoun
>>>> t.
>>>> > validateTasks(GroupByContainerCount.java:212)
>>>> >        at org.apache.samza.container.grouper.task.
>>>> > GroupByContainerCount.group(GroupByContainerCount.java:62)
>>>> >        at org.apache.samza.container.grouper.task.TaskNameGrouper.
>>>> > group(TaskNameGrouper.java:56)
>>>> >        at org.apache.samza.coordinator.JobModelManager$.readJobModel(
>>>> > JobModelManager.scala:266)
>>>> >        at org.apache.samza.coordinator.JobModelManager.readJobModel(
>>>> > JobModelManager.scala)
>>>> >        at org.apache.samza.zk.ZkJobCoordinator.generateNewJobModel(
>>>> > ZkJobCoordinator.java:306)
>>>> >        at org.apache.samza.zk.ZkJobCoordinator.doOnProcessorChange(
>>>> > ZkJobCoordinator.java:197)
>>>> >        at org.apache.samza.zk.ZkJobCoord
>>>> inator$LeaderElectorListenerIm
>>>> pl.
>>>> > lambda$onBecomingLeader$0(ZkJobCoordinator.java:318)
>>>> >        at org.apache.samza.zk.ScheduleAfterDebounceTime.
>>>> > lambda$getScheduleableAction$0(ScheduleAfterDebounceTime.java:134)
>>>> >        at java.util.concurrent.Executors$RunnableAdapter.
>>>> > call$$$capture(Executors.java:511)
>>>> >        at java.util.concurrent.Executors$RunnableAdapter.
>>>> > call(Executors.java)
>>>> >        at java.util.concurrent.FutureTask.run$$$capture(
>>>> > FutureTask.java:266)
>>>> >        at java.util.concurrent.FutureTask.run(FutureTask.java)
>>>> >        at java.util.concurrent.ScheduledThreadPoolExecutor$
>>>> > ScheduledFutureTask.access$201(ScheduledThreadPoolExecutor.java:180)
>>>> >        at java.util.concurrent.ScheduledThreadPoolExecutor$
>>>> > ScheduledFutureTask.run(ScheduledThreadPoolExecutor.java:293)
>>>> >        at java.util.concurrent.ThreadPoolExecutor.runWorker(
>>>> > ThreadPoolExecutor.java:1142)
>>>> >        at java.util.concurrent.ThreadPoolExecutor$Worker.run(
>>>> > ThreadPoolExecutor.java:617)
>>>> >        at java.lang.Thread.run(Thread.java:745)
>>>> > 2018-03-15 22:34:32 logback 77787 [debounce-thread-0] DEBUG
>>>> > o.a.samza.processor.StreamProcessor - Container is not instantiated
>>>> yet.
>>>> > 2018-03-15 22:34:32 logback 77787 [debounce-thread-0] DEBUG
>>>> > org.I0Itec.zkclient.ZkClient - Closing ZkClient...
>>>> > 2018-03-15 22:34:32 logback 77789
>>>> > [ZkClient-EventThread-15-10.0.127.114:2181]
>>>> > INFO  org.I0Itec.zkclient.ZkEventThread - Terminate ZkClient event
>>>> thread.
>>>> >
>>>> > And then the application continues on with metric reporters, and other
>>>> > debug logging (not actually running the task though)
>>>> >
>>>> > Thanks in advance for the guidance, this has been easier than I
>>>> imagined!
>>>> > I’ll report back when I get more of the Dockerization/Kubernetes
>>>> > running and test it a bit more.
>>>> > Cheers,
>>>> > Thunder
>>>> >
>>>> >
>>>> > From: Jagadish Venkatraman [mailto:jagadish1989@gmail.com]
>>>> > Sent: Thursday, March 15, 2018 14:46
>>>> > To: Thunder Stumpges <tstumpges@ntent.com>
>>>> > Cc: dev@samza.apache.org; tom@recursivedream.com; Yipan@linkedin.com;
>>>> > Yi Pan <nickpan47@gmail.com>
>>>> > Subject: Re: Old style "low level" Tasks with alternative deployment
>>>> > model(s)
>>>> >
>>>> > >>  Thanks for the info on the tradeoffs. That makes a lot of sense. I
>>>> > >> am
>>>> > on-board with using ZkJobCoordinator, sounds like some good benefits
>>>> > over just the Kafka high-level consumer.
>>>> >
>>>> > This certainly looks like the simplest alternative.
>>>> >
>>>> > For your other questions, please find my answers inline.
>>>> >
>>>> > >> Q1: If I use LocalApplicationRunner, It does not use
>>>> > "ProcessJobFactory" (or any StreamJob or *Job classes) correct?
>>>> >
>>>> > Your understanding is correct. It directly instantiates the
>>>> > StreamProcessor, which in-turn creates and runs the SamzaContainer.
>>>> >
>>>> > >> Q2: If I use LocalApplicationRunner, I will need to code myself the
>>>> > loading and rewriting of the Config that is currently handled by
>>>> > JobRunner, correct?
>>>> >
>>>> > I don't think you'll need to do this. IIUC, the LocalApplicationRunner
>>>> > should automatically invoke rewriters and do the right thing.
>>>> >
>>>> > >>  Q3: Do I need to also handle coordinator stream(s) and storing of
>>>> > config that is done in JobRunner (I don’t think so as the ?
>>>> >
>>>> > I don't think this is necessary either. The creation of coordinator
>>>> > stream and persisting configuration happens in the
>>>> > LocalApplicationRunner (more specifically in
>>>> StreamManager#createStreams).
>>>> >
>>>> > >> Q4: Where/How do I specify the Container ID for each instance? Is
>>>> > >> there
>>>> > a config setting that I can pass, (or pull from an env variable and
>>>> > add to the config) ? I am assuming it is my responsibility to ensure
>>>> > that each instance is started with a unique container ID..?
>>>> >
>>>> > Nope, If you are using the ZkJobCoordinator, you need not have to
>>>> > worry about assigning IDs for each instance. The framework will
>>>> > automatically take care of generating IDs and reaching consensus by
>>>> > electing a leader. If you are curious please take a look at
>>>> > implementations of the ProcessorIdGenerator interface.
>>>> >
>>>> > Please let us know should you have further questions!
>>>> >
>>>> > Best,
>>>> > Jagdish
>>>> >
>>>> > On Thu, Mar 15, 2018 at 11:48 AM, Thunder Stumpges
>>>> > <tstumpges@ntent.com <mailto:tstumpges@ntent.com>> wrote:
>>>> >
>>>> > Thanks for the info on the tradeoffs. That makes a lot of sense. I am
>>>> > on-board with using ZkJobCoordinator, sounds like some good benefits
>>>> > over just the Kafka high-level consumer.
>>>> >
>>>> >
>>>> >
>>>> > To that end, I have made some notes on possible approaches based on
>>>> > the previous thread, and from my look into the code. I’d love to get
>>>> feedback.
>>>> >
>>>> >
>>>> >
>>>> > Approach 1. Configure jobs to use “ProcessJobFactory” and run
>>>> > instances of the job using run-job.sh or using JobRunner directly.
>>>> >
>>>> > I don’t think this makes sense from what I can see for a few reasons:
>>>> >
>>>> >   *   JobRunner is concerned with stuff I don't *think* we need:
>>>> >
>>>> >      *   coordinatorSystemProducer|Consumer,
>>>> >      *   writing/reading the configuration to the coordinator streams
>>>> >
>>>> >   *   ProcessJobFactory hard-codes the ID to “0” so I don’t think that
>>>> > will work for multiple instances.
>>>> >
>>>> >
>>>> >
>>>> > Approach 2. Configure ZkJobCoordinator, GroupByContainerIds, and
>>>> > invoke
>>>> > LocalApplicationRunner.runTask()
>>>> >
>>>> >
>>>> >
>>>> >     Q1: If I use LocalApplicationRunner, It does not use
>>>> > "ProcessJobFactory" (or any StreamJob or *Job classes) correct?
>>>> >
>>>> >     Q2: If I use LocalApplicationRunner, I will need to code myself
>>>> > the loading and rewriting of the Config that is currently handled by
>>>> > JobRunner, correct?
>>>> >
>>>> >     Q3: Do I need to also handle coordinator stream(s) and storing of
>>>> > config that is done in JobRunner (I don’t think so as the ?
>>>> >
>>>> >     Q4: Where/How do I specify the Container ID for each instance? Is
>>>> > there a config setting that I can pass, (or pull from an env variable
>>>> > and add to the config) ? I am assuming it is my responsibility to
>>>> > ensure that each instance is started with a unique container ID..?
>>>> >
>>>> > I am getting started on the above (Approach 2.), and looking closer at
>>>> > the code so I may have my own answers to my questions, but figured I
>>>> > should go ahead and ask now anyway. Thanks!
>>>> >
>>>> > -Thunder
>>>> >
>>>> >
>>>> > From: Jagadish Venkatraman [mailto:jagadish1989@gmail.com<mailto:
>>>> > jagadish1989@gmail.com>]
>>>> > Sent: Thursday, March 15, 2018 1:41
>>>> > To: dev@samza.apache.org<mailto:dev@samza.apache.org>; Thunder
>>>> > Stumpges < tstumpges@ntent.com<mailto:tstumpges@ntent.com>>;
>>>> > tom@recursivedream.com <mailto:tom@recursivedream.com>
>>>> > Cc: Yipan@linkedin.com<mailto:Yipan@linkedin.com>; Yi Pan <
>>>> > nickpan47@gmail.com<mailto:nickpan47@gmail.com>>
>>>> >
>>>> > Subject: Re: Old style "low level" Tasks with alternative deployment
>>>> > model(s)
>>>> >
>>>> > >> You are correct that this is focused on the higher-level API but
>>>> > >> doesn't
>>>> > preclude using the lower-level API. I was at the same point you were
>>>> > not long ago, in fact, and had a very productive conversation on the
>>>> > list
>>>> >
>>>> > Thanks Tom for linking the thread, and I'm glad that you were able to
>>>> > get Kubernetes integration working with Samza.
>>>> >
>>>> > >> If it is helpful for everyone, once I get the low-level API +
>>>> > >> ZkJobCoordinator + Docker +
>>>> > K8s working, I'd be glad to formulate an additional sample for
>>>> hello-samza.
>>>> >
>>>> > @Thunder Stumpges:
>>>> > We'd be thrilled to receive your contribution. Examples, demos,
>>>> > tutorials etc.
>>>> > contribute a great deal to improving the ease of use of Apache Samza.
>>>> > I'm happy to shepherd design discussions/code-reviews in the
>>>> > open-source including answering any questions you may have.
>>>> >
>>>> >
>>>> > >> One thing I'm still curious about, is what are the drawbacks or
>>>> > >> complexities of leveraging the Kafka High-level consumer +
>>>> > >> PassthroughJobCoordinator in a stand-alone setup like this? We do
>>>> > >> have Zookeeper (because of kafka) so I think either would work. The
>>>> > >> Kafka High-level consumer comes with other nice tools for
>>>> > >> monitoring offsets, lag, etc
>>>> >
>>>> >
>>>> > @Thunder Stumpges:
>>>> >
>>>> > Samza uses a "Job-Coordinator" to assign your input-partitions among
>>>> > the different instances of your application s.t. they don't overlap. A
>>>> > typical way to solve this "partition distribution"
>>>> > problem is to have a single instance elected as a "leader" and have
>>>> > the leader assign partitions to the group.
>>>> > The ZkJobCoordinator uses Zk primitives to achieve this, while the
>>>> > YarnJC relies on Yarn's guarantee that there will be a
>>>> > singleton-AppMaster to achieve this.
>>>> >
>>>> > A key difference that separates the PassthroughJC from the Yarn/Zk
>>>> > variants is that it does _not_ attempt to solve the "partition
>>>> > distribution" problem. As a result, there's no leader-election
>>>> involved.
>>>> > Instead, it pushes the problem of "partition distribution" to the
>>>> > underlying consumer.
>>>> >
>>>> > The PassThroughJc supports these 2 scenarios:
>>>> >
>>>> > 1. Consumer-managed partition distribution: When using the Kafka
>>>> > high-level consumer (or an AWS KinesisClientLibrary consumer) with
>>>> > Samza, the consumer manages partitions internally.
>>>> >
>>>> > 2. Static partition distribution: Alternately, partitions can be
>>>> > managed statically using configuration. You can achieve static
>>>> > partition assignment by implementing a custom
>>>> > SystemStreamPartitionGrouper<h
>>>> > ttps://samza.apache.org/learn/documentation/0.8/api/
>>>> > javadocs/org/apache/samza/container/grouper/stream/
>>>> > SystemStreamPartitionGrouper.html> and TaskNameGrouper<https://
>>>> > github.com/apache/samza/blob/master/samza-core/src/main/
>>>> > java/org/apache/samza/container/grouper/task/TaskNameGrouper.java>.
>>>> > Solutions in this category will typically require you to distinguish
>>>> > the various processors in the group by providing an "id" for each.
>>>> > Once the "id"s are decided, you can then statically compute
>>>> > assignments using a function (eg: modulo N).
>>>> > You can rely on the following mechanisms to provide this id:
>>>> >  - Configure each instance differently to have its own id
>>>> >  - Obtain the id from the cluster-manager. For instance, Kubernetes
>>>> > will provide each POD an unique id in the range [0,N). AWS ECS should
>>>> > expose similar capabilities via a REST end-point.
>>>> >
>>>> > >> One thing I'm still curious about, is what are the drawbacks or
>>>> > complexities of leveraging the Kafka High-level consumer +
>>>> > PassthroughJobCoordinator in a stand-alone setup like this?
>>>> >
>>>> > Leveraging the Kafka High-level consumer:
>>>> >
>>>> > The Kafka high-level consumer is not integrated into Samza just yet.
>>>> > Instead, Samza's integration with Kafka uses the low-level consumer
>>>> > because
>>>> > i) It allows for greater control in fetching data from individual
>>>> brokers.
>>>> > It is simple and performant in-terms of the threading model to have
>>>> > one-thread pull from each broker.
>>>> > ii) It is efficient in memory utilization since it does not do
>>>> > internal-buffering of messages.
>>>> > iii) There's no overhead like Kafka-controller heart-beats that are
>>>> > driven by consumer.poll
>>>> >
>>>> > Since there's no built-in integration, you will have to build a new
>>>> > SystemConsumer if you need to integrate with the Kafka High-level
>>>> consumer.
>>>> > Further, there's more a fair bit of complexity to manage in
>>>> checkpointing.
>>>> >
>>>> > >> The Kafka High-level consumer comes with other nice tools for
>>>> > >> monitoring offsets, lag, etc
>>>> >
>>>> > Samza exposes<https://github.com/apache/samza/blob/master/
>>>> > samza-kafka/src/main/scala/org/apache/samza/system/kafka/
>>>> > KafkaSystemConsumerMetrics.scala> the below metrics for
>>>> lag-monitoring:
>>>> > - The current log-end offset for each partition
>>>> > - The last check-pointed offset for each partition
>>>> > - The number of messages behind the highwatermark of the partition
>>>> >
>>>> > Please let us know if you need help discovering these or integrating
>>>> > these with other systems/tools.
>>>> >
>>>> >
>>>> > Leveraging the Passthrough JobCoordinator:
>>>> >
>>>> > It's helpful to split this discussion on tradeoffs with PassthroughJC
>>>> > into
>>>> > 2 parts:
>>>> >
>>>> > 1. PassthroughJC + consumer managed partitions:
>>>> >
>>>> > - In this model, Samza has no control over partition-assignment since
>>>> > it's managed by the consumer. This means that stateful operations like
>>>> > joins that rely on partitions being co-located on the same task will
>>>> not work.
>>>> > Simple stateless operations (eg: map, filter, remote lookups) are
>>>> fine.
>>>> >
>>>> > - A key differentiator between Samza and other frameworks is our
>>>> > support for "host
>>>> > affinity<https://samza.apache.org/learn/documentation/0.14/
>>>> > yarn/yarn-host-affinity.html>". Samza achieves this by assigning
>>>> > partitions to hosts taking data-locality into account. If the consumer
>>>> > can arbitrarily shuffle partitions, it'd be hard to support this
>>>> > affinity/locality. Often this is a key optimization when dealing with
>>>> > large stateful jobs.
>>>> >
>>>> > 2. PassthroughJC + static partitions:
>>>> >
>>>> > - In this model, it is possible to make stateful processing (including
>>>> > host affinity) work by carefully choosing how "id"s are assigned and
>>>> > computed.
>>>> >
>>>> > Recommendation:
>>>> >
>>>> > - Owing to the above subtleties, I would recommend that we give the
>>>> > ZkJobCoordinator + the built-in low-level Kafka integration a try.
>>>> > - If we hit snags down this path, we can certainly explore the
>>>> > approach with PassthroughJC + static partitions.
>>>> > - Using the PassthroughJC + consumer-managed distribution would be
>>>> > least preferable owing to the subtleties I outlined above.
>>>> >
>>>> > Please let us know should you have more questions.
>>>> >
>>>> > Best,
>>>> > Jagdish
>>>> >
>>>> > On Wed, Mar 14, 2018 at 9:24 PM, Thunder Stumpges <
>>>> tstumpges@ntent.com
>>>> > <mailto:tstumpges@ntent.com>> wrote:
>>>> > Wow, what great timing, and what a great thread! I definitely have
>>>> > some good starters to go off of here.
>>>> >
>>>> > If it is helpful for everyone, once I get the low-level API +
>>>> > ZkJobCoordinator + Docker + K8s working, I'd be glad to formulate an
>>>> > additional sample for hello-samza.
>>>> >
>>>> > One thing I'm still curious about, is what are the drawbacks or
>>>> > complexities of leveraging the Kafka High-level consumer +
>>>> > PassthroughJobCoordinator in a stand-alone setup like this? We do have
>>>> > Zookeeper (because of kafka) so I think either would work. The Kafka
>>>> > High-level consumer comes with other nice tools for monitoring
>>>> > offsets, lag, etc....
>>>> >
>>>> > Thanks guys!
>>>> > -Thunder
>>>> >
>>>> > -----Original Message-----
>>>> > From: Tom Davis [mailto:tom@recursivedream.com<mailto:
>>>> > tom@recursivedream.com>]
>>>> > Sent: Wednesday, March 14, 2018 17:50
>>>> > To: dev@samza.apache.org<mailto:dev@samza.apache.org>
>>>> > Subject: Re: Old style "low level" Tasks with alternative deployment
>>>> > model(s)
>>>> >
>>>> > Hey there!
>>>> >
>>>> > You are correct that this is focused on the higher-level API but
>>>> > doesn't preclude using the lower-level API. I was at the same point
>>>> > you were not long ago, in fact, and had a very productive conversation
>>>> on the list:
>>>> > you should look for "Question about custom StreamJob/Factory" in the
>>>> > list archive for the past couple months.
>>>> >
>>>> > I'll quote Jagadish Venkatraman from that thread:
>>>> >
>>>> > > For the section on the low-level API, can you use
>>>> > > LocalApplicationRunner#runTask()? It basically creates a new
>>>> > > StreamProcessor and runs it. Remember to provide task.class and set
>>>> > > it to your implementation of StreamTask or AsyncStreamTask. Please
>>>> > > note that this is an evolving API and hence, subject to change.
>>>> >
>>>> > I ended up just switching to the high-level API because I don't have
>>>> > any existing Tasks and the Kubernetes story is a little more straight
>>>> > forward there (there's only one container/configuration to deploy).
>>>> >
>>>> > Best,
>>>> >
>>>> > Tom
>>>> >
>>>> > Thunder Stumpges <tstumpges@ntent.com<mailto:tstumpges@ntent.com>>
>>>> writes:
>>>> >
>>>> > > Hi all,
>>>> > >
>>>> > > We are using Samza (0.12.0) in about 2 dozen jobs implementing
>>>> > > several processing pipelines. We have also begun a significant move
>>>> > > of other services within our company to Docker/Kubernetes. Right now
>>>> > > our Hadoop/Yarn cluster has a mix of stream and batch "Map Reduce"
>>>> > > jobs
>>>> > (many reporting and other batch processing jobs). We would really like
>>>> > to move our stream processing off of Hadoop/Yarn and onto Kubernetes.
>>>> > >
>>>> > > When I just read about some of the new progress in .13 and .14 I got
>>>> > > really excited! We would love to have our jobs run as simple
>>>> > > libraries in our own JVM, and use the Kafka High-Level-Consumer for
>>>> > > partition
>>>> > distribution and such. This would let us "dockerfy" our application
>>>> > and run/scale in kubernetes.
>>>> > >
>>>> > > However as I read it, this new deployment model is ONLY for the
>>>> > > new(er) High Level API, correct? Is there a plan and/or resources
>>>> > > for adapting this back to existing low-level tasks ? How complicated
>>>> > > of a
>>>> > task is that? Do I have any other options to make this transition
>>>> easier?
>>>> > >
>>>> > > Thanks in advance.
>>>> > > Thunder
>>>> >
>>>> >
>>>> >
>>>> > --
>>>> > Jagadish V,
>>>> > Graduate Student,
>>>> > Department of Computer Science,
>>>> > Stanford University
>>>> >
>>>> >
>>>> >
>>>> > --
>>>> > Jagadish V,
>>>> > Graduate Student,
>>>> > Department of Computer Science,
>>>> > Stanford University
>>>> >
>>>>
>>>>
>>>
>>>


-- 
Jagadish V,
Graduate Student,
Department of Computer Science,
Stanford University

Mime
  • Unnamed multipart/alternative (inline, None, 0 bytes)
View raw message