Satish Duggana created CURATOR-358:
--------------------------------------

             Summary: Receiving KeeperException with NoNode when 
LeaderLatch#getLeader()
                 Key: CURATOR-358
                 URL: https://issues.apache.org/jira/browse/CURATOR-358
             Project: Apache Curator
          Issue Type: Bug
          Components: Recipes
    Affects Versions: 2.10.0
            Reporter: Satish Duggana
            Priority: Critical


org.apache.curator.framework.recipes.leader.LeaderLatch#getLeader() throws 
KeeperException with Code#NONODE intermittently 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
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)




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