You are right, Joe. I checked our brokers' log. We have three brokers. All of
them failed to connect to zk at some point.
So they were offline and later reregistered themselves with the zk. I don't
know how many rebalance should be
triggered in that case. There is only one exception found in consumer's log. My
question is whether users need to do
anything to handle ConsumerRebalanceFailedException.
This is from consumer log:
[28/11/13 16:38:56:056 PM EST] 102 ERROR consumer.ZookeeperConsumerConnector:
[xxxxxxxxxx
], error during syncedRebalance
kafka.common.ConsumerRebalanceFailedException: xxxxxxxxx can't rebalance after
4 retries
at
kafka.consumer.ZookeeperConsumerConnector$ZKRebalancerListener.syncedReb
alance(ZookeeperConsumerConnector.scala:397)
at
kafka.consumer.ZookeeperConsumerConnector$ZKRebalancerListener$$anon$1.r
un(ZookeeperConsumerConnector.scala:326)
Regards,
Libo
-----Original Message-----
From: Joe Stein [mailto:joe.st...@stealth.ly]
Sent: Friday, November 29, 2013 11:57 AM
To: users@kafka.apache.org
Subject: Re: ConsumerRebalanceFailedException
What is the full stack trace? if you see "can't rebalance after 4 retries"
then likely the problem is the broker is down or not available
/*******************************************
Joe Stein
Founder, Principal Consultant
Big Data Open Source Security LLC
http://www.stealth.ly
Twitter: @allthingshadoop <http://www.twitter.com/allthingshadoop>
********************************************/
On Fri, Nov 29, 2013 at 11:31 AM, Yu, Libo <libo...@citi.com> wrote:
> We found our consumer stopped working after this exception occurred.
> Can the consumer recover from such an exception?
>
> Regards,
>
> Libo
>
>
> -----Original Message-----
> From: Florin Trofin [mailto:ftro...@adobe.com]
> Sent: Tuesday, July 16, 2013 4:20 PM
> To: users@kafka.apache.org
> Subject: Re: ConsumerRebalanceFailedException
>
> Yes, I think these are two separate issues.
>
> F.
>
> On 7/16/13 11:32 AM, "Joel Koshy" <jjkosh...@gmail.com> wrote:
>
> >From a user's perspective, ConsumerRebalanceException is a bit
> >cryptic -I think the other thread was to provide a more informative
> >message and also be able to recover when a broker does come up (fixed
> >in KAFKA-969).
> >
> >Thanks,
> >
> >Joel
> >
> >On Tue, Jul 16, 2013 at 11:04 AM, Vaibhav Puranik
> ><vpura...@gmail.com>
> >wrote:
> >> Thank you Joel.
> >>
> >> In a different but related thread, somebody is asking to rename the
> >> exception as NoBrokerAvailableExcption. But given the description
> >> above, the exception seems to be named appropriately.
> >>
> >> Regards,
> >> Vaibhav
> >>
> >>
> >> On Tue, Jul 16, 2013 at 12:05 AM, Joel Koshy <jjkosh...@gmail.com>
> >>wrote:
> >>
> >>> Yes - rebalance => consumers trying to coordinate through ZK.
> >>> Rebalances can happen when one or more of the following happen:
> >>> - a consumed topic partition appears or disappears - i.e., if a
> >>> broker comes or goes.
> >>> - a consumer instance in the group comes or goes "goes" could also
> >>> be triggered by session expirations in zookeeper - typically
> >>> caused by client-side GC or flaky connections to zookeeper.
> >>>
> >>> On Mon, Jul 15, 2013 at 10:15 AM, Vaibhav Puranik
> >>> <vpura...@gmail.com>
> >>> wrote:
> >>> > Hi all,
> >>> >
> >>> > We have a small Kafka cluster (0.7.1 - 3 nodes) in EC2. The load
> >>> > is
> >>>about
> >>> > 200 million events per day, each being few kilobytes. We have a
> >>>single
> >>> node
> >>> > zookeeper.
> >>> >
> >>> > Yesterday suddenly our Kafka clients started throwing the
> >>> > following
> >>> > exception:
> >>> > java.lang.RuntimeException:
> >>> kafka.common.ConsumerRebalanceFailedException:
> >>> >
> >>>CONSUMER_GROUP_NAME_ip-00-00-00-00.ec2.internal-1373821190828-5f78e
> >>>9a
> >>>f
> >>> > can't rebalance after 4 retries
> >>> > at
> >>> >
> >>>
> >>>com.gumgum.kafka.consumer.KafkaTemplate.executeWithBatch(KafkaTempl
> >>>at
> >>>e.j
> >>>ava:59)
> >>> > at
> >>> >
> >>>
> >>>com.gumgum.storm.fileupload.GenericKafkaSpout.nextTuple(GenericKafk
> >>>aS
> >>>pou
> >>>t.java:73)
> >>> > at
> >>> >
> >>>
> >>>backtype.storm.daemon.executor$fn__3968$fn__4009$fn__4010.invoke(ex
> >>>ec
> >>>uto
> >>>r.clj:433)
> >>> > at
> >>> > backtype.storm.util$async_loop$fn__465.invoke(util.clj:377)
> >>> >
> >>> > None of the Kafka clients (ConsumerConenctor class) would start.
> >>> > They
> >>> would
> >>> > fail with the exception.
> >>> >
> >>> > We tried restarting the clilents, restarting the zookeeper as well.
> >>>But
> >>> > finally it all started working when we restarted all of our
> >>> > kafka
> >>> brokers.
> >>> > We didn't lose any data because producers (going directly to the
> >>>brokers
> >>> > through a load balancer) were working fine.
> >>> >
> >>> > I tried googling this issue and looks like lot of people have
> >>> > faced
> >>>it,
> >>> but
> >>> > couldn't get anything concrete.
> >>> >
> >>> > Given this, I have two questions:
> >>> >
> >>> > It will be nice if you can tell me why this can happen or point
> >>> > me
> >>>to a
> >>> > link where I can understand it better. What does Consumer
> >>> > Rebalancing
> >>> mean?
> >>> > Does that mean consumers are trying to coordinate amongst
> >>> > themselves
> >>> using
> >>> > Zookeeper?
> >>> >
> >>> > On a separate note, are there any JMX parameters I need to be
> >>>monitoring
> >>> to
> >>> > make sure that my kafka cluster is healthy? How can I keep watch
> >>> > on
> >>>my
> >>> > kafka cluster?
> >>> >
> >>> > Regards,
> >>> > Vaibhav Puranik
> >>> > GumGum
> >>>
>
>
