Details
Major Description
The Zookeeper quorum, containing 5 servers, didn't provide service when restart after an "Out of memory" crash.
It happened as following:
1. we built a Zookeeper quorum which contained 5 servers, say 1, 3, 4, 5, 6 (have no 2), and 6 was the leader.
2. we created 18 threads on 6 different servers to set and get data from a znode in the Zookeeper at the same time. The size of the data is 1MB. The test threads did their job as fast as possible, no pause between two operation, and they repeated the setting and getting 4000 times.
3. the Zookeeper leader crashed about 10 mins after the test threads started. The leader printed out the log:
2009-08-25 12:00:12,301 - WARN [NIOServerCxn.Factory:2181:NIOServerCnxn@497] - Exception causing close of session 0x523
4223c2dc00b5 due to java.io.IOException: Read error
2009-08-25 12:00:12,318 - WARN [NIOServerCxn.Factory:2181:NIOServerCnxn@497] - Exception causing close of session 0x523
4223c2dc00b6 due to java.io.IOException: Read error
2009-08-25 12:03:44,086 - WARN [NIOServerCxn.Factory:2181:NIOServerCnxn@497] - Exception causing close of session 0x523
4223c2dc00b8 due to java.io.IOException: Read error
2009-08-25 12:04:53,757 - WARN [NIOServerCxn.Factory:2181:NIOServerCnxn@497] - Exception causing close of session 0x523
4223c2dc00b7 due to java.io.IOException: Read error
2009-08-25 12:15:45,151 - FATAL [SyncThread:0:SyncRequestProcessor@131] - Severe unrecoverable error, exiting
java.lang.OutOfMemoryError: Java heap space
at java.util.Arrays.copyOf(Arrays.java:2786)
at java.io.ByteArrayOutputStream.write(ByteArrayOutputStream.java:71)
at java.io.DataOutputStream.writeInt(DataOutputStream.java:180)
at org.apache.jute.BinaryOutputArchive.writeInt(BinaryOutputArchive.java:55)
at org.apache.zookeeper.txn.SetDataTxn.serialize(SetDataTxn.java:42)
at org.apache.zookeeper.server.persistence.Util.marshallTxnEntry(Util.java:262)
at org.apache.zookeeper.server.persistence.FileTxnLog.append(FileTxnLog.java:154)
at org.apache.zookeeper.server.persistence.FileTxnSnapLog.append(FileTxnSnapLog.java:268)
at org.apache.zookeeper.server.SyncRequestProcessor.run(SyncRequestProcessor.java:100)
It is clear that the leader ran out of memory. then the server 4 was down almost at the same time, and printed out the log:
2009-08-25 12:15:45,995 - ERROR [FollowerRequestProcessor:3:FollowerRequestProcessor@91] - Unexpected exception causing
exit
java.net.SocketException: Connection reset
at java.net.SocketOutputStream.socketWrite(SocketOutputStream.java:96)
at java.net.SocketOutputStream.write(SocketOutputStream.java:136)
at java.io.BufferedOutputStream.write(BufferedOutputStream.java:105)
at java.io.DataOutputStream.write(DataOutputStream.java:90)
at java.io.FilterOutputStream.write(FilterOutputStream.java:80)
at org.apache.jute.BinaryOutputArchive.writeBuffer(BinaryOutputArchive.java:119)
at org.apache.zookeeper.server.quorum.QuorumPacket.serialize(QuorumPacket.java:51)
at org.apache.jute.BinaryOutputArchive.writeRecord(BinaryOutputArchive.java:123)
at org.apache.zookeeper.server.quorum.Follower.writePacket(Follower.java:97)
at org.apache.zookeeper.server.quorum.Follower.request(Follower.java:399)
at org.apache.zookeeper.server.quorum.FollowerRequestProcessor.run(FollowerRequestProcessor.java:86)
2009-08-25 12:15:45,996 - WARN [NIOServerCxn.Factory:2181:NIOServerCnxn@497] - Exception causing close of session 0x423
4ab894330075 due to java.net.SocketException: Broken pipe
2009-08-25 12:15:45,996 - FATAL [SyncThread:3:SyncRequestProcessor@131] - Severe unrecoverable error, exiting
java.net.SocketException: Broken pipe
at java.net.SocketOutputStream.socketWrite0(Native Method)
at java.net.SocketOutputStream.socketWrite(SocketOutputStream.java:92)
at java.net.SocketOutputStream.write(SocketOutputStream.java:136)
at java.io.BufferedOutputStream.flushBuffer(BufferedOutputStream.java:65)
at java.io.BufferedOutputStream.flush(BufferedOutputStream.java:123)
at org.apache.zookeeper.server.quorum.Follower.writePacket(Follower.java:100)
at org.apache.zookeeper.server.quorum.SendAckRequestProcessor.flush(SendAckRequestProcessor.java:52)
at org.apache.zookeeper.server.SyncRequestProcessor.flush(SyncRequestProcessor.java:147)
at org.apache.zookeeper.server.SyncRequestProcessor.run(SyncRequestProcessor.java:92)
2009-08-25 12:15:45,995 - WARN [QuorumPeer:/0.0.0.0:2181:Follower@309] - Exception when following the leader
java.net.SocketException: Broken pipe
at java.net.SocketOutputStream.socketWrite0(Native Method)
at java.net.SocketOutputStream.socketWrite(SocketOutputStream.java:92)
at java.net.SocketOutputStream.write(SocketOutputStream.java:136)
at java.io.BufferedOutputStream.flushBuffer(BufferedOutputStream.java:65)
at java.io.BufferedOutputStream.flush(BufferedOutputStream.java:123)
at org.apache.zookeeper.server.quorum.Follower.writePacket(Follower.java:100)
at org.apache.zookeeper.server.quorum.Follower.followLeader(Follower.java:256)
at org.apache.zookeeper.server.quorum.QuorumPeer.run(QuorumPeer.java:498)
2009-08-25 12:15:46,022 - WARN [NIOServerCxn.Factory:2181:NIOServerCnxn@497] - Exception causing close of session 0x0 d
ue to java.io.IOException: ZooKeeperServer not running
2009-08-25 12:15:46,022 - WARN [NIOServerCxn.Factory:2181:NIOServerCnxn@497] - Exception causing close of session 0x0 d
ue to java.io.IOException: ZooKeeperServer not running
2009-08-25 12:15:46,023 - WARN [NIOServerCxn.Factory:2181:NIOServerCnxn@497] - Exception causing close of session 0x0 d
ue to java.io.IOException: ZooKeeperServer not running
It was really strange that when the 2 server down, the other three servers cannot provide service any more, the 'stat' command all leaded to "ZooKeeperServer not running".
4. I restarted the server 6(the former leader) and the server 4. But the service didn't come back. All the five servers printed "ZookeeperServer not running". The server 6 printed the logs:
2009-08-25 14:02:15,395 - WARN [NIOServerCxn.Factory:2181:NIOServerCnxn@497] - Exception causing close of session 0x0 d
ue to java.io.IOException: ZooKeeperServer not running
2009-08-25 14:02:27,703 - WARN [NIOServerCxn.Factory:2181:NIOServerCnxn@497] - Exception causing close of session 0x0 d
ue to java.io.IOException: Responded to info probe
2009-08-25 14:02:28,733 - WARN [NIOServerCxn.Factory:2181:NIOServerCnxn@497] - Exception causing close of session 0x0 d
ue to java.io.IOException: ZooKeeperServer not running
2009-08-25 14:02:42,070 - WARN [NIOServerCxn.Factory:2181:NIOServerCnxn@497] - Exception causing close of session 0x0 d
ue to java.io.IOException: ZooKeeperServer not running
2009-08-25 14:02:55,407 - WARN [NIOServerCxn.Factory:2181:NIOServerCnxn@497] - Exception causing close of session 0x0 d
ue to java.io.IOException: ZooKeeperServer not running
2009-08-25 14:03:08,744 - WARN [NIOServerCxn.Factory:2181:NIOServerCnxn@497] - Exception causing close of session 0x0 d
ue to java.io.IOException: ZooKeeperServer not running
2009-08-25 14:03:22,080 - WARN [NIOServerCxn.Factory:2181:NIOServerCnxn@497] - Exception causing close of session 0x0 d
ue to java.io.IOException: ZooKeeperServer not running
2009-08-25 14:03:29,396 - ERROR [main:Util@238] - Last transaction was partial.
2009-08-25 14:03:35,417 - WARN [NIOServerCxn.Factory:2181:NIOServerCnxn@497] - Exception causing close of session 0x0 d
ue to java.io.IOException: ZooKeeperServer not running
2009-08-25 14:03:48,761 - WARN [NIOServerCxn.Factory:2181:NIOServerCnxn@497] - Exception causing close of session 0x0 d
ue to java.io.IOException: ZooKeeperServer not running
The server 4 printed logs like:
2009-08-25 14:03:48,747 - WARN [NIOServerCxn.Factory:2181:NIOServerCnxn@497] - Exception causing close of session 0x0 d
ue to java.io.IOException: ZooKeeperServer not running
2009-08-25 14:04:02,091 - WARN [NIOServerCxn.Factory:2181:NIOServerCnxn@497] - Exception causing close of session 0x0 d
ue to java.io.IOException: ZooKeeperServer not running
2009-08-25 14:04:15,427 - WARN [NIOServerCxn.Factory:2181:NIOServerCnxn@497] - Exception causing close of session 0x0 d
ue to java.io.IOException: ZooKeeperServer not running
2009-08-25 14:04:17,816 - WARN [QuorumPeer:/0.0.0.0:2181:Follower@164] - Unexpected exception, tries=0
java.net.ConnectException: Connection refused
at java.net.PlainSocketImpl.socketConnect(Native Method)
at java.net.PlainSocketImpl.doConnect(PlainSocketImpl.java:333)
at java.net.PlainSocketImpl.connectToAddress(PlainSocketImpl.java:195)
at java.net.PlainSocketImpl.connect(PlainSocketImpl.java:182)
at java.net.SocksSocketImpl.connect(SocksSocketImpl.java:366)
at java.net.Socket.connect(Socket.java:525)
at org.apache.zookeeper.server.quorum.Follower.followLeader(Follower.java:156)
at org.apache.zookeeper.server.quorum.QuorumPeer.run(QuorumPeer.java:498)
2009-08-25 14:04:18,820 - WARN [QuorumPeer:/0.0.0.0:2181:Follower@164] - Unexpected exception, tries=1
java.net.ConnectException: Connection refused
at java.net.PlainSocketImpl.socketConnect(Native Method)
at java.net.PlainSocketImpl.doConnect(PlainSocketImpl.java:333)
at java.net.PlainSocketImpl.connectToAddress(PlainSocketImpl.java:195)
at java.net.PlainSocketImpl.connect(PlainSocketImpl.java:182)
at java.net.SocksSocketImpl.connect(SocksSocketImpl.java:366)
at java.net.Socket.connect(Socket.java:525)
at org.apache.zookeeper.server.quorum.Follower.followLeader(Follower.java:156)
at org.apache.zookeeper.server.quorum.QuorumPeer.run(QuorumPeer.java:498)
2009-08-25 14:04:19,823 - WARN [QuorumPeer:/0.0.0.0:2181:Follower@164] - Unexpected exception, tries=2
java.net.ConnectException: Connection refused
at java.net.PlainSocketImpl.socketConnect(Native Method)
at java.net.PlainSocketImpl.doConnect(PlainSocketImpl.java:333)
at java.net.PlainSocketImpl.connectToAddress(PlainSocketImpl.java:195)
at java.net.PlainSocketImpl.connect(PlainSocketImpl.java:182)
at java.net.SocksSocketImpl.connect(SocksSocketImpl.java:366)
at java.net.Socket.connect(Socket.java:525)
at org.apache.zookeeper.server.quorum.Follower.followLeader(Follower.java:156)
at org.apache.zookeeper.server.quorum.QuorumPeer.run(QuorumPeer.java:498)
2009-08-25 14:04:28,764 - WARN [NIOServerCxn.Factory:2181:NIOServerCnxn@497] - Exception causing close of session 0x0 d
ue to java.io.IOException: ZooKeeperServer not running
2009-08-25 14:04:42,101 - WARN [NIOServerCxn.Factory:2181:NIOServerCnxn@497] - Exception causing close of session 0x0 d
ue to java.io.IOException: ZooKeeperServer not running
the server 1, 3, 5 printed out the logs like:
2009-08-25 14:01:35,396 - WARN [NIOServerCxn.Factory:2181:NIOServerCnxn@497] - Exception causing close of session 0x0 d
ue to java.io.IOException: ZooKeeperServer not running
2009-08-25 14:01:36,554 - WARN [QuorumPeer:/0.0.0.0:2181:LeaderElection@194] - Ignoring exception while looking for lea
der
java.net.SocketTimeoutException: Receive timed out
at java.net.PlainDatagramSocketImpl.receive0(Native Method)
at java.net.PlainDatagramSocketImpl.receive(PlainDatagramSocketImpl.java:136)
at java.net.DatagramSocket.receive(DatagramSocket.java:712)
at org.apache.zookeeper.server.quorum.LeaderElection.lookForLeader(LeaderElection.java:170)
at org.apache.zookeeper.server.quorum.QuorumPeer.run(QuorumPeer.java:488)
2009-08-25 14:01:37,758 - WARN [QuorumPeer:/0.0.0.0:2181:LeaderElection@194] - Ignoring exception while looking for lea
der
java.net.SocketTimeoutException: Receive timed out
at java.net.PlainDatagramSocketImpl.receive0(Native Method)
at java.net.PlainDatagramSocketImpl.receive(PlainDatagramSocketImpl.java:136)
at java.net.DatagramSocket.receive(DatagramSocket.java:712)
at org.apache.zookeeper.server.quorum.LeaderElection.lookForLeader(LeaderElection.java:170)
at org.apache.zookeeper.server.quorum.QuorumPeer.run(QuorumPeer.java:488)
2009-08-25 14:01:37,865 - WARN [QuorumPeer:/0.0.0.0:2181:Follower@164] - Unexpected exception, tries=0
java.net.ConnectException: Connection refused
at java.net.PlainSocketImpl.socketConnect(Native Method)
at java.net.PlainSocketImpl.doConnect(PlainSocketImpl.java:333)
at java.net.PlainSocketImpl.connectToAddress(PlainSocketImpl.java:195)
at java.net.PlainSocketImpl.connect(PlainSocketImpl.java:182)
at java.net.SocksSocketImpl.connect(SocksSocketImpl.java:366)
at java.net.Socket.connect(Socket.java:525)
at org.apache.zookeeper.server.quorum.Follower.followLeader(Follower.java:156)
at org.apache.zookeeper.server.quorum.QuorumPeer.run(QuorumPeer.java:498)
2009-08-25 14:01:38,289 - WARN [NIOServerCxn.Factory:2181:NIOServerCnxn@497] - Exception causing close of session 0x0 d
ue to java.io.IOException: Responded to info probe
my zoo.cfg is like:
tickTime=2000
dataDir=./status/
clientPort=2181
initLimit=10
syncLimit=2
server.1=10.81.11.107:2888:3888
server.2=10.81.11.106:2888:3888
server.3=10.81.11.89:2888:3888
server.4=10.81.11.99:2888:3888
server.5=10.81.11.79:2888:3888
Several questions:
1. Why the leader selection failed after the restart?
2. Is the size of data too big to be processed properly?
3. How can I recover from this situation? Can I just remove the version-2 directory on server 6(the former leader) and restart the server?