Hi, We are having issues with our web interface (WI) to zookeeper. We deployed a java app (WI), in tomcat, which shows a (mostly read-only) UI for the zk tree, in our cluster. The app had been deployed quite some time ago. However, recently, it is going down many times, in the recent past, showing these errors in the catalina.out. These errors are coming continuously in the catalina.out, while the website is down.
<catalina.out> [INFO] SyncZKTreeWatcher - [registerWatches] About to register watch for '/llf/version-1.0/serverNodes/llf-server/nodes/b3091258:8085/connected', recursive: false [INFO] SyncZKTreeWatcher - Path: null, type: None, state: Disconnected [INFO] SyncZKTreeWatcher - Path: null, type: None, state: SyncConnected [WARN] SyncZKTreeWatcher - [run] Exception while handling event WatchedEvent: Znode change. Path: /llf/version-1.0/serverNodes/llf-server/nodes/b3091258:8085/connected Type: NodeChildrenChanged <org.apache.zookeeper.KeeperException$ConnectionLossException: KeeperErrorCode = ConnectionLoss>org.apache.zookeeper.KeeperException$ConnectionLossException: KeeperErrorCode = ConnectionLoss at org.apache.zookeeper.KeeperException.create(KeeperException.java:90) at org.apache.zookeeper.ZooKeeper.getData(ZooKeeper.java:809) at org.apache.zookeeper.ZooKeeper.getData(ZooKeeper.java:837) at com.yahoo.cluster.zookeeper.SyncZKTreeWatcher.getNodeValue(SyncZKTreeWatcher.java:465) at com.yahoo.cluster.zookeeper.SyncZKTreeWatcher.registerWatches(SyncZKTreeWatcher.java:376) at com.yahoo.cluster.zookeeper.SyncZKTreeWatcher.access$100(SyncZKTreeWatcher.java:37) at com.yahoo.cluster.zookeeper.SyncZKTreeWatcher$1.run(SyncZKTreeWatcher.java:169) at java.lang.Thread.run(Thread.java:619) </catalina.out> In another log, we are getting the following errors continuously. <AlertReceiver.log> java.net.SocketException: Transport endpoint is not connected at sun.nio.ch.SocketChannelImpl.shutdown(Native Method) at sun.nio.ch.SocketChannelImpl.shutdownOutput(SocketChannelImpl.java:651) at sun.nio.ch.SocketAdaptor.shutdownOutput(SocketAdaptor.java:368) at org.apache.zookeeper.ClientCnxn$SendThread.cleanup(ClientCnxn.java:935) at org.apache.zookeeper.ClientCnxn$SendThread.run(ClientCnxn.java:901) 2010 03 16 09:49:55,645 org.apache.zookeeper.ClientCnxn ZK Event Handler-SendThread Attempting connection to server b3091279.crawl.yahoo.net/18.104.22.168:22801 2010 03 16 09:49:55,646 org.apache.zookeeper.ClientCnxn ZK Event Handler-SendThread Priming connection to java.nio.channels.SocketChannel[connected local=/22.214.171.124:38793 remote=b3091279.crawl.yahoo.net/126.96.36.199:22801] 2010 03 16 09:49:55,739 org.apache.zookeeper.ClientCnxn ZK Event Handler-SendThread Server connection successful 2010 03 16 09:49:55,775 org.apache.zookeeper.ClientCnxn ZK Event Handler-SendThread Exception closing session 0xe727001201aa32ab to sun.nio.ch.selectionkeyi...@3ef92f5e<mailto:sun.nio.ch.selectionkeyi...@3ef92f5e> java.io.IOException: Read error rc = -1 java.nio.DirectByteBuffer[pos=0 lim=4 cap=4] at org.apache.zookeeper.ClientCnxn$SendThread.doIO(ClientCnxn.java:632) at org.apache.zookeeper.ClientCnxn$SendThread.run(ClientCnxn.java:876) 2010 03 16 09:49:55,775 org.apache.zookeeper.ClientCnxn ZK Event Handler-SendThread Ignoring exception during shutdown input </AlertReceiver.log> What do these errors indicate? Always, restarting tomcat helps. But since the problem is occurring many times, we want to understand why is this happening? Is there a known ZK issue which could cause such behavior? Thanks Udaya