CODEWITHSUNDEEP
apache-zookeeperapache-curator
Kunal P.Bharati
Kunal P.Bharati

Reputation: 969

Leader election with Curator and Zookeeper

I am running 3 instances of ZooKeeper and the config is this:

tickTime=2000
initLimit=10
syncLimit=5
dataDir=/tmp/zookeeper1
clientPort=2181
maxClientCnxns=1000
server.1=127.0.0.1:2888:3888
server.2=127.0.0.1:2889:3889
server.3=127.0.0.1:2890:3890

I am using the leader election example code given here: https://git-wip-us.apache.org/repos/asf?p=curator.git;a=tree;f=curator-examples/src/main/java/leader;h=73b547eadb98995c0ccbd06a5b76d0741ffef263;hb=HEAD

The code runs fine with TestingServer but when I change connection string to : "127.0.0.1:2181,127.0.0.1:2182,127.0.0.1:2183", I get the exceptions:

[main-SendThread(127.0.0.1:2183)] INFO org.apache.zookeeper.ClientCnxn - Opening socket connection to server 127.0.0.1/127.0.0.1:2183. Will not attempt to authenticate using SASL (unknown error)
[main-SendThread(127.0.0.1:2183)] INFO org.apache.zookeeper.ClientCnxn - Socket connection established, initiating session, client: /127.0.0.1:56111, server: 127.0.0.1/127.0.0.1:2183
[main-SendThread(127.0.0.1:2183)] INFO org.apache.zookeeper.ClientCnxn - Session establishment complete on server 127.0.0.1/127.0.0.1:2183, sessionid = 0x3521552283c0000, negotiated timeout = 40000
[main-EventThread] INFO org.apache.curator.framework.state.ConnectionStateManager - State change: CONNECTED
[main-SendThread(127.0.0.1:2183)] INFO org.apache.zookeeper.ClientCnxn - Unable to read additional data from server sessionid 0x3521552283c0000, likely server has closed socket, closing socket connection and attempting reconnect
[main-EventThread] INFO org.apache.curator.framework.imps.EnsembleTracker - New config event received: null
[main-EventThread] ERROR org.apache.curator.framework.imps.CuratorFrameworkImpl - Background exception was not retry-able or retry gave up
java.lang.NullPointerException
    at java.io.ByteArrayInputStream.<init>(ByteArrayInputStream.java:106)
    at org.apache.curator.framework.imps.EnsembleTracker.processConfigData(EnsembleTracker.java:163)
    at org.apache.curator.framework.imps.EnsembleTracker.access$200(EnsembleTracker.java:48)
    at org.apache.curator.framework.imps.EnsembleTracker$2.processResult(EnsembleTracker.java:134)
    at org.apache.curator.framework.imps.CuratorFrameworkImpl.sendToBackgroundCallback(CuratorFrameworkImpl.java:829)
    at org.apache.curator.framework.imps.CuratorFrameworkImpl.processBackgroundOperation(CuratorFrameworkImpl.java:611)
    at org.apache.curator.framework.imps.WatcherRemovalFacade.processBackgroundOperation(WatcherRemovalFacade.java:151)
    at org.apache.curator.framework.imps.GetConfigBuilderImpl$2.processResult(GetConfigBuilderImpl.java:210)
    at org.apache.zookeeper.ClientCnxn$EventThread.processEvent(ClientCnxn.java:619)
    at org.apache.zookeeper.ClientCnxn$EventThread.run(ClientCnxn.java:528)
[main-EventThread] INFO org.apache.curator.framework.state.ConnectionStateManager - State change: SUSPENDED

What could be the issue?

Upvotes: 5

Views: 2194

Answers (2)

Edward Lee
Edward Lee

Reputation: 111

If use Zookeeper 3.5.1, then curator-recipes 3.2.1+ fix this issue.

Upvotes: 0

Guest
Guest

Reputation: 1

I am hitting the same issue. I think it might be related to the Zookeeper 3.5.1 ClientCnxn. Even though I return back to curator 2.6.0, I still see the same stack trace. A GET_CONFIG event type is sent without the event data.

My stack trace looks like this:

org.apache.curator.framework.imps.CuratorFrameworkImpl: Background exception was not retry-able or retry gave up
! java.lang.NullPointerException: null
! at java.io.ByteArrayInputStream.(ByteArrayInputStream.java:106)
! at org.apache.curator.framework.imps.EnsembleTracker.processConfigData(EnsembleTracker.java:163)
! at org.apache.curator.framework.imps.EnsembleTracker.access$200(EnsembleTracker.java:48)
! at org.apache.curator.framework.imps.EnsembleTracker$2.processResult(EnsembleTracker.java:134)
! at org.apache.curator.framework.imps.CuratorFrameworkImpl.sendToBackgroundCallback(CuratorFrameworkImpl.java:829)
! at org.apache.curator.framework.imps.CuratorFrameworkImpl.processBackgroundOperation(CuratorFrameworkImpl.java:611)
! at org.apache.curator.framework.imps.WatcherRemovalFacade.processBackgroundOperation(WatcherRemovalFacade.java:151)
! at org.apache.curator.framework.imps.GetConfigBuilderImpl$2.processResult(GetConfigBuilderImpl.java:210)
! at org.apache.zookeeper.ClientCnxn$EventThread.processEvent(ClientCnxn.java:619)
! at org.apache.zookeeper.ClientCnxn$EventThread.run(ClientCnxn.java:528)

Upvotes: 0

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