Please open an issue at http://issues.apache.org/jira/browse/CURATOR <http://issues.apache.org/jira/browse/CURATOR>. Thank you.
-JZ > On Nov 17, 2016, at 11:43 PM, Satish Duggana <[email protected]> wrote: > > Hi, > In some scenarios, > org.apache.curator.framework.recipes.leader.LeaderLatch#getLeader() throws > KeeperException with Code#NONODE as mentioned in the stack trace below. It > may be possible participant's ephemeral ZK node is removed because its > connection/session is closed. > > You can see the below code at > https://github.com/apache/curator/blob/master/curator-recipes/src/main/java/org/apache/curator/framework/recipes/leader/LeaderLatch.java#L451 > > <https://github.com/apache/curator/blob/master/curator-recipes/src/main/java/org/apache/curator/framework/recipes/leader/LeaderLatch.java#L451> > public Participant getLeader() throws Exception > { > Collection<String> participantNodes = > LockInternals.getParticipantNodes(client, latchPath, LOCK_NAME, sorter); > return LeaderSelector.getLeader(client, participantNodes); > } > > I guess it hits a race condition where a participant node is retrieved but > when it invokes LeaderSelector#getLeader() it would have been removed because > of session timeout and it throws KeeperException with NoNode code. It does > not retry as the RetryLoop retries only for connection/session timeouts. But > in this case, NoNode should have been retried. I could not find any APIs on > CuratorClient to configure the kind of KeeperException codes to be retried. > It may be good to have a way to take what kind of errors should be retried in > org.apache.curator.framework.CuratorFrameworkFactory.Builder APIs. > > Intermittent Exception found with the stack trace: > 2016-11-15 06:09:33.954 o.a.s.d.nimbus [ERROR] Error when processing event > org.apache.storm.shade.org.apache.zookeeper.KeeperException$NoNodeException: > KeeperErrorCode = NoNode for > /storm/leader-lock/_c_97c09eed-5bba-4ac8-a05f-abdc4e8e95cf-latch-0000000002 > at > org.apache.storm.shade.org.apache.zookeeper.KeeperException.create(KeeperException.java:111) > at > org.apache.storm.shade.org.apache.zookeeper.KeeperException.create(KeeperException.java:51) > at > org.apache.storm.shade.org.apache.zookeeper.ZooKeeper.getData(ZooKeeper.java:1155) > at > org.apache.storm.shade.org.apache.curator.framework.imps.GetDataBuilderImpl$4.call(GetDataBuilderImpl.java:304) > at > org.apache.storm.shade.org.apache.curator.framework.imps.GetDataBuilderImpl$4.call(GetDataBuilderImpl.java:293) > at > org.apache.storm.shade.org.apache.curator.RetryLoop.callWithRetry(RetryLoop.java:108) > at > org.apache.storm.shade.org.apache.curator.framework.imps.GetDataBuilderImpl.pathInForeground(GetDataBuilderImpl.java:290) > at > org.apache.storm.shade.org.apache.curator.framework.imps.GetDataBuilderImpl.forPath(GetDataBuilderImpl.java:281) > at > org.apache.storm.shade.org.apache.curator.framework.imps.GetDataBuilderImpl.forPath(GetDataBuilderImpl.java:42) > at > org.apache.storm.shade.org.apache.curator.framework.recipes.leader.LeaderSelector.participantForPath(LeaderSelector.java:375) > at > org.apache.storm.shade.org.apache.curator.framework.recipes.leader.LeaderSelector.getLeader(LeaderSelector.java:346) > at > org.apache.storm.shade.org.apache.curator.framework.recipes.leader.LeaderLatch.getLeader(LeaderLatch.java:454) > > > Thanks, > Satish.
