Hey just reporting that the ZK disconnect tip on the FAQ was in fact right on the money. After tweaking our GC settings and zk timeout settings, I'm no longer seeing the flood of rebalances.
-- Ian Friedman On Tuesday, August 20, 2013 at 2:26 AM, Ian Friedman wrote: > Sorry, ignore that first exception, I believe that was caused by an actual > manual shutdown. The NoNode exception though, has been popping up a lot, and > I am not sure if it's relevant, but it seems to show up a bunch when the > consumers decide it's time to rebalance continuously. > > -- > Ian Friedman > > > On Tuesday, August 20, 2013 at 2:17 AM, Ian Friedman wrote: > > > That's not it either. I just had all my consumers shut down on me with > > this: > > > > INFO 21:51:13,948 () ZkUtils$ - conflict in > > /consumers/flurry1/owners/dataLogPaths/1-183 data: > > flurry1_hs1030-1376964634130-dcc9192a-0 stored data: > > flurry1_hs1061-1376964609207-4b7f348b-0 > > INFO 21:51:13,948 () ZookeeperConsumerConnector - > > flurry1_hs1030-1376964634130-dcc9192a waiting for the partition ownership > > to be deleted: 1-183 > > INFO 21:51:13,950 () ZookeeperConsumerConnector - > > flurry1_hs1030-1376964634130-dcc9192a > > flurry1_hs1030-1376964634130-dcc9192a-0 successfully owned partition 1-180 > > for topic dataLogPaths > > > > > > > > and I've also been seeing: > > > > INFO 21:51:15,971 () ZookeeperConsumerConnector - > > flurry1_hs1030-1376964634130-dcc9192a begin rebalancing consumer > > flurry1_hs1030-1376964634130-dcc9192a try #3 > > INFO 21:51:16,038 () ZookeeperConsumerConnector - > > flurry1_hs1030-1376964634130-dcc9192a exception during rebalance > > org.I0Itec.zkclient.exception.ZkNoNodeException: > > org.apache.zookeeper.KeeperException$NoNodeException: KeeperErrorCode = > > NoNode for /consumers/flurry1/ids/flurry1_hs676-1376964612747-6f532caa > > at > > org.I0Itec.zkclient.exception.ZkException.create(ZkException.java:47) > > at > > org.I0Itec.zkclient.ZkClient.retryUntilConnected(ZkClient.java:685) > > at org.I0Itec.zkclient.ZkClient.readData(ZkClient.java:766) > > at org.I0Itec.zkclient.ZkClient.readData(ZkClient.java:761) > > at org.I0Itec.zkclient.ZkClient.readData(ZkClient.java:750) > > at org.I0Itec.zkclient.ZkClient.readData(ZkClient.java:744) > > at kafka.utils.ZkUtils$.readData(ZkUtils.scala:162) > > at > > kafka.consumer.TopicCount$.constructTopicCount(TopicCount.scala:66) > > at > > kafka.utils.ZkUtils$$anonfun$getConsumersPerTopic$1.apply(ZkUtils.scala:259) > > at > > kafka.utils.ZkUtils$$anonfun$getConsumersPerTopic$1.apply(ZkUtils.scala:258) > > at scala.collection.Iterator$class.foreach(Iterator.scala:631) > > at > > scala.collection.JavaConversions$JIteratorWrapper.foreach(JavaConversions.scala:474) > > at > > scala.collection.IterableLike$class.foreach(IterableLike.scala:79) > > at > > scala.collection.JavaConversions$JListWrapper.foreach(JavaConversions.scala:521) > > at kafka.utils.ZkUtils$.getConsumersPerTopic(ZkUtils.scala:258) > > at > > kafka.consumer.ZookeeperConsumerConnector$ZKRebalancerListener.kafka$consumer$ZookeeperConsumerConnector$ZKRebalancerListener$$rebalance(ZookeeperConsumerConnector.scala:478) > > at > > kafka.consumer.ZookeeperConsumerConnector$ZKRebalancerListener$$anonfun$syncedRebalance$1.apply$mcVI$sp(ZookeeperConsumerConnector.scala:449) > > at > > scala.collection.immutable.Range$ByOne$class.foreach$mVc$sp(Range.scala:285) > > at > > scala.collection.immutable.Range$$anon$2.foreach$mVc$sp(Range.scala:265) > > at > > kafka.consumer.ZookeeperConsumerConnector$ZKRebalancerListener.syncedRebalance(ZookeeperConsumerConnector.scala:444) > > at > > kafka.consumer.ZookeeperConsumerConnector$ZKRebalancerListener$$anon$1.run(ZookeeperConsumerConnector.scala:401) > > Caused by: org.apache.zookeeper.KeeperException$NoNodeException: > > KeeperErrorCode = NoNode for > > /consumers/flurry1/ids/flurry1_hs676-1376964612747-6f532caa > > at > > org.apache.zookeeper.KeeperException.create(KeeperException.java:111) > > at > > org.apache.zookeeper.KeeperException.create(KeeperException.java:51) > > at org.apache.zookeeper.ZooKeeper.getData(ZooKeeper.java:1151) > > at org.apache.zookeeper.ZooKeeper.getData(ZooKeeper.java:1180) > > at org.I0Itec.zkclient.ZkConnection.readData(ZkConnection.java:103) > > at org.I0Itec.zkclient.ZkClient$9.call(ZkClient.java:770) > > at org.I0Itec.zkclient.ZkClient$9.call(ZkClient.java:766) > > at > > org.I0Itec.zkclient.ZkClient.retryUntilConnected(ZkClient.java:675) > > ... 19 more > > INFO 21:51:16,039 () ZookeeperConsumerConnector - > > flurry1_hs1030-1376964634130-dcc9192a end rebalancing consumer > > flurry1_hs1030-1376964634130-dcc9192a try #3 > > > > > > any ideas? > > > > -- > > Ian Friedman > > > > > > On Monday, August 19, 2013 at 11:58 PM, Jun Rao wrote: > > > > > Any failure/restart of a consumer or a broker can also trigger a > > > rebalance. > > > > > > Thanks, > > > > > > Jun > > > > > > > > > On Mon, Aug 19, 2013 at 6:00 PM, Ian Friedman <i...@flurry.com > > > (mailto:i...@flurry.com)> wrote: > > > > > > > Jun, I read that FAQ entry you linked, but I am not seeing any Zookeeper > > > > connection loss in the logs. It's rebalancing multiple times per minute, > > > > though. Any idea what else could cause this? We're running kafka 0.7.2 > > > > on > > > > approx 400 consumers against a topic with 400 partitions * 3 brokers. > > > > > > > > -- > > > > Ian Friedman > > > > > > > > > > > > On Thursday, August 15, 2013 at 11:52 AM, Jun Rao wrote: > > > > > > > > > Yes, during rebalances, messages could be re-delievered since the new > > > > owner > > > > > of a partition starts fetching from the last checkpointed offset in > > > > > ZK. > > > > > > > > > > For reasons on why rebalances happen a lot, see > > > > https://cwiki.apache.org/confluence/display/KAFKA/FAQ#FAQ-Whyaretheremanyrebalancesinmyconsumerlog%3F > > > > > > > > > > Thanks, > > > > > > > > > > Jun > > > > > > > > > > > > > > > On Thu, Aug 15, 2013 at 8:36 AM, Ian Friedman <i...@flurry.com > > > > > (mailto:i...@flurry.com) (mailto: > > > > i...@flurry.com (mailto:i...@flurry.com))> wrote: > > > > > > > > > > > It's a simple enough patch, but wouldn't this mean that messages > > > > > > still > > > > in > > > > > > process when a rebalance happens could get delivered to another > > > > > > > > > > > > > consumer if > > > > > > we end up losing the partition? Rebalances seem to happen very > > > > > > > > > > > > > frequently > > > > > > with a lot of consumers for some reason… And it doesn't seem like a > > > > > > consumer is guaranteed or likely to retain ownership of a partition > > > > > > > > > > > > > > > > > > > it's in > > > > > > the middle of consuming after a rebalance. > > > > > > > > > > > > -- > > > > > > Ian Friedman > > > > > > > > > > > > > > > > > > On Thursday, August 15, 2013 at 10:53 AM, Jun Rao wrote: > > > > > > > > > > > > > We are only patching blocker issues in 0.7. 0.8 beta1 has been > > > > released > > > > > > and > > > > > > > most dev effort will be on 0.8 and beyond. That said. This > > > > > > > particular > > > > > > > > > > > > > > > > > > case > > > > > > > is easy to fix. If you can port the patch in > > > > > > > https://issues.apache.org/jira/browse/KAFKA-919 o the 0.7 branch , > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > we > > > > > > > > > > > > > > > > > > > > > > > > > can > > > > > > > commit that to the 0.7 branch. > > > > > > > > > > > > > > Thanks, > > > > > > > > > > > > > > Jun > > > > > > > > > > > > > > > > > > > > > On Wed, Aug 14, 2013 at 9:30 PM, Ian Friedman <i...@flurry.com > > > > > > > (mailto:i...@flurry.com)(mailto: > > > > i...@flurry.com (mailto:i...@flurry.com)) (mailto: > > > > > > i...@flurry.com (mailto:i...@flurry.com) (mailto:i...@flurry.com))> > > > > > > wrote: > > > > > > > > > > > > > > > Ugh. > > > > > > > > > > > > > > > > Is there any way to make this work in 0.7, or is transitioning > > > > > > > > to > > > > 0.8 > > > > > > the > > > > > > > > only way? My operations engineers spent a lot of effort in > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > configuring > > > > > > > > > > > > > > > > > > > > > > > > > and > > > > > > > > hardening our 0.7 production install, and 0.8 isn't released > > > > > > > > yet. > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > Not > > > > > > > > > > > > > > > > > > > > > > > > > to > > > > > > > > mention having to integrate the new client side code. > > > > > > > > > > > > > > > > Either way, thanks for all your help Jun. > > > > > > > > > > > > > > > > -- > > > > > > > > Ian Friedman > > > > > > > > > > > > > > > > > > > > > > > > On Thursday, August 15, 2013 at 12:21 AM, Jun Rao wrote: > > > > > > > > > > > > > > > > > Yes, this is an issue and has been fixed in 0.8. > > > > > > > > > > > > > > > > > > Thanks, > > > > > > > > > > > > > > > > > > Jun > > > > > > > > > > > > > > > > > > > > > > > > > > > On Wed, Aug 14, 2013 at 5:21 PM, Ian Friedman > > > > > > > > > <i...@flurry.com (mailto:i...@flurry.com)(mailto: > > > > i...@flurry.com (mailto:i...@flurry.com))(mailto: > > > > > > i...@flurry.com (mailto:i...@flurry.com) (mailto:i...@flurry.com)) > > > > > > (mailto: > > > > > > > > i...@flurry.com (mailto:i...@flurry.com) > > > > > > > > (mailto:i...@flurry.com))> wrote: > > > > > > > > > > > > > > > > > > > Hey guys, > > > > > > > > > > > > > > > > > > > > I designed my consumer app (running on 0.7) to run with > > > > autocommit > > > > > > off > > > > > > > > and > > > > > > > > > > commit manually once it was done processing a record. The > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > intent > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > was so > > > > > > > > > > that if a consumer died while processing a message, the > > > > > > > > > > offset > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > would > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > not be > > > > > > > > > > committed, and another box would pick up the partition and > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > reprocess > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > the > > > > > > > > > > message. This seemed to work fine with small numbers of > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > consumers > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > (~10). > > > > > > > > > > But now that I'm scaling it out, I'm running into a problem > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > where > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > it > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > looks > > > > > > > > > > like messages that consumers picked up and then errored on > > > > > > > > > > are > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > not > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > getting > > > > > > > > > > processed on another machine. > > > > > > > > > > > > > > > > > > > > After investigating the logs and the partition offsets in > > > > > > zookeeper, I > > > > > > > > > > found that in ZookeeperConsumerConnector.scala > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > closeFetchersForQueues, > > > > > > > > > > called during the rebalance process, will commit the offset > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > regardless > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > of > > > > > > > > > > the autocommit status. So it looks like even if my consumer > > > > > > > > > > is > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > in > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > the > > > > > > > > > > middle of processing a message, the offset will be > > > > > > > > > > committed, > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > and > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > even > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > if > > > > > > > > > > the processing fails, it will never be picked up again. Now > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > that I > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > have a > > > > > > > > > > lot of consumer nodes, the rebalancer is going off a lot > > > > > > > > > > more > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > often > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > and I'm > > > > > > > > > > running into this constantly. > > > > > > > > > > > > > > > > > > > > Were my assumptions faulty? Did I design this wrong? After > > > > reading > > > > > > the > > > > > > > > > > comment in the code I understand that if it didn't commit > > > > > > > > > > the > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > offset > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > there, > > > > > > > > > > the message would just get immediately consumed by whoever > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > ended up > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > owning > > > > > > > > > > the partition, even if we were in the middle of consuming it > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > elsewhere, and > > > > > > > > > > we'd get unintentional duplicate delivery. How can I make it > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > work > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > the > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > way > > > > > > > > > > I've described? Is there any way? > > > > > > > > > > > > > > > > > > > > Thanks in advance, > > > > > > > > > > > > > > > > > > > > -- > > > > > > > > > > Ian Friedman > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > >
