Hi Tao, We see this error from time to time but did not think of this as a big issue. Any reason it bothers you much? I¹m not sure if throwing exception to user on this exception is a good handling or not. What are user supposed to do in that case other than retry?
Thanks, Jiangjie (Becket) Qin On 7/12/15, 7:16 PM, "tao xiao" <xiaotao...@gmail.com> wrote: >We saw the error again in our cluster. Anyone has the same issue before? > >On Fri, 10 Jul 2015 at 13:26 tao xiao <xiaotao...@gmail.com> wrote: > >> Bump the thread. Any help would be appreciated. >> >> On Wed, 8 Jul 2015 at 20:09 tao xiao <xiaotao...@gmail.com> wrote: >> >>> Additional info >>> Kafka version: 0.8.2.1 >>> zookeeper: 3.4.6 >>> >>> On Wed, 8 Jul 2015 at 20:07 tao xiao <xiaotao...@gmail.com> wrote: >>> >>>> Hi team, >>>> >>>> I have 10 high level consumers connecting to Kafka and one of them >>>>kept >>>> complaining "conflicted ephemeral node" for about 8 hours. The log was >>>> filled with below exception >>>> >>>> [2015-07-07 14:03:51,615] INFO conflict in >>>> /consumers/group/ids/test-1435856975563-9a9fdc6c data: >>>> >>>>{"version":1,"subscription":{"test.*":1},"pattern":"white_list","timest >>>>amp":"1436275631510"} >>>> stored data: >>>> >>>>{"version":1,"subscription":{"test.*":1},"pattern":"white_list","timest >>>>amp":"1436275558570"} >>>> (kafka.utils.ZkUtils$) >>>> [2015-07-07 14:03:51,616] INFO I wrote this conflicted ephemeral node >>>> >>>>[{"version":1,"subscription":{"test.*":1},"pattern":"white_list","times >>>>tamp":"1436275631510"}] >>>> at /consumers/group/ids/test-1435856975563-9a9fdc6c a while back in a >>>> different session, hence I will backoff for this node to be deleted by >>>> Zookeeper and retry (kafka.utils.ZkUtils$) >>>> >>>> In the meantime zookeeper reported below exception for the same time >>>>span >>>> >>>> 2015-07-07 22:45:09,687 [myid:3] - INFO [ProcessThread(sid:3 >>>> cport:-1)::PrepRequestProcessor@645] - Got user-level KeeperException >>>> when processing sessionid:0x44e657ff19c0019 type:create cxid:0x7a26 >>>> zxid:0x3015f6e77 txntype:-1 reqpath:n/a Error >>>> Path:/consumers/group/ids/test-1435856975563-9a9fdc6c >>>>Error:KeeperErrorCode >>>> = NodeExists for /consumers/group/ids/test-1435856975563-9a9fdc6c >>>> >>>> At the end zookeeper timed out the session and consumers triggered >>>> rebalance. >>>> >>>> I know that conflicted ephemeral node warning is to handle a zookeeper >>>> bug that session expiration and ephemeral node deletion are not done >>>> atomically but as indicated from zookeeper log the zookeeper never >>>>got a >>>> chance to delete the ephemeral node which made me think that the >>>>session >>>> was not expired at that time. And for some reason zookeeper fired >>>>session >>>> expire event which subsequently invoked ZKSessionExpireListener. I >>>>was >>>> just wondering if anyone have ever encountered similar issue before >>>>and >>>> what I can do at zookeeper side to prevent this? >>>> >>>> Another problem is that createEphemeralPathExpectConflictHandleZKBug >>>> call is wrapped in a while(true) loop which runs forever until the >>>> ephemeral node is created. Would it be better that we can employ an >>>> exponential retry policy with a max number of retries so that it has a >>>> chance to re-throw the exception back to caller and let caller handle >>>>it in >>>> situation like above? >>>> >>>>