[ZOOKEEPER-785] Zookeeper 3.3.1 shouldn't infinite loop if someone creates a server.0 line

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 3.3.1
• Fix Version/s: 3.3.2, 3.4.0
• Component/s: server

Environment

Tested in linux with a new jvm

• Hadoop Flags: Reviewed
• Assignee: Patrick D. Hunt
• Reporter: Alex Newman
• Created: 02/Jun/10 22:51
• Updated: 23/Nov/11 19:22
• Resolved: 14/Sep/10 21:09

Description

The following config causes an infinite loop

[zoo.cfg]
tickTime=2000
dataDir=/var/zookeeper/
clientPort=2181
initLimit=10
syncLimit=5
server.0=localhost:2888:3888

Output:

2010-06-01 16:20:32,471 - INFO [main:QuorumPeerMain@119] - Starting quorum peer
2010-06-01 16:20:32,489 - INFO [main:NIOServerCnxn$Factory@143] - binding to port 0.0.0.0/0.0.0.0:2181
2010-06-01 16:20:32,504 - INFO [main:QuorumPeer@818] - tickTime set to 2000
2010-06-01 16:20:32,504 - INFO [main:QuorumPeer@829] - minSessionTimeout set to -1
2010-06-01 16:20:32,505 - INFO [main:QuorumPeer@840] - maxSessionTimeout set to -1
2010-06-01 16:20:32,505 - INFO [main:QuorumPeer@855] - initLimit set to 10
2010-06-01 16:20:32,526 - INFO [main:FileSnap@82] - Reading snapshot /var/zookeeper/version-2/snapshot.c
2010-06-01 16:20:32,547 - INFO [Thread-1:QuorumCnxManager$Listener@436] - My election bind port: 3888
2010-06-01 16:20:32,554 - INFO [QuorumPeer:/0:0:0:0:0:0:0:0:2181:QuorumPeer@620] - LOOKING
2010-06-01 16:20:32,556 - INFO [QuorumPeer:/0:0:0:0:0:0:0:0:2181:FastLeaderElection@649] - New election. My id = 0, Proposed zxid = 12
2010-06-01 16:20:32,558 - INFO [QuorumPeer:/0:0:0:0:0:0:0:0:2181:FastLeaderElection@689] - Notification: 0, 12, 1, 0, LOOKING, LOOKING, 0
2010-06-01 16:20:32,560 - WARN [QuorumPeer:/0:0:0:0:0:0:0:0:2181:QuorumPeer@623] - Unexpected exception
java.lang.NullPointerException
at org.apache.zookeeper.server.quorum.FastLeaderElection.totalOrderPredicate(FastLeaderElection.java:496)
at org.apache.zookeeper.server.quorum.FastLeaderElection.lookForLeader(FastLeaderElection.java:709)
at org.apache.zookeeper.server.quorum.QuorumPeer.run(QuorumPeer.java:621)
2010-06-01 16:20:32,560 - INFO [QuorumPeer:/0:0:0:0:0:0:0:0:2181:QuorumPeer@620] - LOOKING
2010-06-01 16:20:32,560 - INFO [QuorumPeer:/0:0:0:0:0:0:0:0:2181:FastLeaderElection@649] - New election. My id = 0, Proposed zxid = 12
2010-06-01 16:20:32,561 - INFO [QuorumPeer:/0:0:0:0:0:0:0:0:2181:FastLeaderElection@689] - Notification: 0, 12, 2, 0, LOOKING, LOOKING, 0
2010-06-01 16:20:32,561 - WARN [QuorumPeer:/0:0:0:0:0:0:0:0:2181:QuorumPeer@623] - Unexpected exception
java.lang.NullPointerException
at org.apache.zookeeper.server.quorum.FastLeaderElection.totalOrderPredicate(FastLeaderElection.java:496)
at org.apache.zookeeper.server.quorum.FastLeaderElection.lookForLeader(FastLeaderElection.java:709)
at org.apache.zookeeper.server.quorum.QuorumPeer.run(QuorumPeer.java:621)
2010-06-01 16:20:32,561 - INFO [QuorumPeer:/0:0:0:0:0:0:0:0:2181:QuorumPeer@620] - LOOKING
2010-06-01 16:20:32,562 - INFO [QuorumPeer:/0:0:0:0:0:0:0:0:2181:FastLeaderElection@649] - New election. My id = 0, Proposed zxid = 12
2010-06-01 16:20:32,562 - INFO [QuorumPeer:/0:0:0:0:0:0:0:0:2181:FastLeaderElection@689] - Notification: 0, 12, 3, 0, LOOKING, LOOKING, 0
2010-06-01 16:20:32,562 - WARN [QuorumPeer:/0:0:0:0:0:0:0:0:2181:QuorumPeer@623] - Unexpected exception
java.lang.NullPointerException

Things like HBase require that the zookeeper servers be listed in the zoo.cfg. This is a bug on their part, but zookeeper shouldn't null pointer in a loop though.