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","timestamp":"1436275631510"}
>> stored data:
>> {"version":1,"subscription":{"test.*":1},"pattern":"white_list","timestamp":"1436275558570"}
>> (kafka.utils.ZkUtils$)
>> [2015-07-07 14:03:51,616] INFO I wrote this conflicted ephemeral node
>> [{"version":1,"subscription":{"test.*":1},"pattern":"white_list","timestamp":"1436275631510"}]
>> at /consumers/group/ids/test-1435856975563-9a9fdc6c a while back in a
>> different session, hence I will backoff for this node to be deleted by
>> Zookeeper and retry (kafka.utils.ZkUtils$)
>>
>> 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?
>>
>>
