[ZOOKEEPER-2938] Server is unable to join quorum after connection broken to other peers

• Type: Bug
• Status: Open
• Priority: Major
• Resolution: Unresolved
• Affects Version/s: 3.4.6, 3.4.14
• Assignee: Unassigned
• Reporter: Abhay Bothra
• Created: 09/Nov/17 00:31
• Updated: 11/Aug/23 06:26

Description

We see the following logs in the node with myid: 1

2017-11-08 15:06:28,375 [myid:1] - INFO  [WorkerSender[myid=1]:QuorumCnxManager@193] - Have smaller server identifier, so dropping the connection: (2, 1)
2017-11-08 15:06:28,375 [myid:1] - INFO  [WorkerSender[myid=1]:QuorumCnxManager@193] - Have smaller server identifier, so dropping the connection: (3, 1)
2017-11-08 15:07:28,375 [myid:1] - INFO  [WorkerReceiver[myid=1]:FastLeaderElection@597] - Notification: 1 (message format version), 1 (n.leader), 0x28e000a8750 (n.zxid), 0x1 (n.round), LOOKING (n.state), 1 (n.sid), 0x28e (n.peerEpoch) LOOKING (my state)
2017-11-08 15:07:28,375 [myid:1] - INFO  [WorkerSender[myid=1]:QuorumCnxManager@193] - Have smaller server identifier, so dropping the connection: (2, 1)
2017-11-08 15:07:28,376 [myid:1] - INFO  [WorkerSender[myid=1]:QuorumCnxManager@193] - Have smaller server identifier, so dropping the connection: (3, 1)
2017-11-08 15:08:28,375 [myid:1] - INFO  [WorkerReceiver[myid=1]:FastLeaderElection@597] - Notification: 1 (message format version), 1 (n.leader), 0x28e000a8750 (n.zxid), 0x1 (n.round), LOOKING (n.state), 1 (n.sid), 0x28e (n.peerEpoch) LOOKING (my state)
2017-11-08 15:08:28,376 [myid:1] - INFO  [WorkerSender[myid=1]:QuorumCnxManager@193] - Have smaller server identifier, so dropping the connection: (2, 1)
2017-11-08 15:08:28,376 [myid:1] - INFO  [WorkerSender[myid=1]:QuorumCnxManager@193] - Have smaller server identifier, so dropping the connection: (3, 1)
2017-11-08 15:09:28,376 [myid:1] - INFO  [WorkerReceiver[myid=1]:FastLeaderElection@597] - Notification: 1 (message format version), 1 (n.leader), 0x28e000a8750 (n.zxid), 0x1 (n.round), LOOKING (n.state), 1 (n.sid), 0x28e (n.peerEpoch) LOOKING (my state)
2017-11-08 15:09:28,376 [myid:1] - INFO  [WorkerSender[myid=1]:QuorumCnxManager@193] - Have smaller server identifier, so dropping the connection: (2, 1)
2017-11-08 15:09:28,376 [myid:1] - INFO  [WorkerSender[myid=1]:QuorumCnxManager@193] - Have smaller server identifier, so dropping the connection: (3, 1)
2017-11-08 15:10:28,376 [myid:1] - INFO  [WorkerReceiver[myid=1]:FastLeaderElection@597] - Notification: 1 (message format version), 1 (n.leader), 0x28e000a8750 (n.zxid), 0x1 (n.round), LOOKING (n.state), 1 (n.sid), 0x28e (n.peerEpoch) LOOKING (my state)
2017-11-08 15:10:28,376 [myid:1] - INFO  [WorkerSender[myid=1]:QuorumCnxManager@193] - Have smaller server identifier, so dropping the connection: (2, 1)
2017-11-08 15:10:28,377 [myid:1] - INFO  [WorkerSender[myid=1]:QuorumCnxManager@193] - Have smaller server identifier, so dropping the connection: (3, 1)

On the nodes with myid: 2 and myid: 3, we see connection broken events for myid: 1

2017-11-07 02:54:32,135 [myid:2] - WARN  [RecvWorker:1:QuorumCnxManager$RecvWorker@780] - Connection broken for id 1, my id = 2, error =
java.net.SocketException: Connection reset
        at java.net.SocketInputStream.read(SocketInputStream.java:209)
        at java.net.SocketInputStream.read(SocketInputStream.java:141)
        at java.net.SocketInputStream.read(SocketInputStream.java:223)
        at java.io.DataInputStream.readInt(DataInputStream.java:387)
        at org.apache.zookeeper.server.quorum.QuorumCnxManager$RecvWorker.run(QuorumCnxManager.java:765)
2017-11-07 02:54:32,135 [myid:2] - WARN  [RecvWorker:1:QuorumCnxManager$RecvWorker@783] - Interrupting SendWorker
2017-11-07 02:54:32,135 [myid:2] - WARN  [SendWorker:1:QuorumCnxManager$SendWorker@697] - Interrupted while waiting for message on queue
java.lang.InterruptedException
        at java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject.reportInterruptAfterWait(AbstractQueuedSynchronizer.java:2014)
        at java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject.awaitNanos(AbstractQueuedSynchronizer.java:2088)
        at java.util.concurrent.ArrayBlockingQueue.poll(ArrayBlockingQueue.java:418)
        at org.apache.zookeeper.server.quorum.QuorumCnxManager.pollSendQueue(QuorumCnxManager.java:849)
        at org.apache.zookeeper.server.quorum.QuorumCnxManager.access$500(QuorumCnxManager.java:64)
        at org.apache.zookeeper.server.quorum.QuorumCnxManager$SendWorker.run(QuorumCnxManager.java:685)
2017-11-07 02:54:32,135 [myid:2] - WARN  [SendWorker:1:QuorumCnxManager$SendWorker@706] - Send worker leaving thread

From the reported occurrences, it looks like this is a problem only when the node with the smallest myid loses connection.