[HADOOP-1255] Name-node falls into infinite loop trying to remove a dead node.

• Type: Bug
• Status: Closed
• Priority: Blocker
• Resolution: Fixed
• Affects Version/s: 0.12.3
• Fix Version/s: 0.13.0
• Assignee: Hairong Kuang
• Reporter: Konstantin Shvachko
• Created: 12/Apr/07 18:10
• Updated: 08/Jul/09 16:42
• Resolved: 08/May/07 18:52

Description

Under certain conditions the name-node fall into infinite loop in heartbeatCheck().
It's rather hard to reproduce. I'm running one node cluster: 1 name-node, 1 data-node.
The data-node dies, and 10 minutes later I get

07/04/12 10:40:34 INFO net.NetworkTopology: Removing a node: /default-rack/0.0.0.0:50077
07/04/12 10:44:35 INFO dfs.StateChange: BLOCK* NameSystem.heartbeatCheck: lost heartbeat from 0.0.0.0:50077
...................................................
07/04/12 10:45:17 INFO net.NetworkTopology: Removing a node: /default-rack/0.0.0.0:50077
07/04/12 10:47:44 INFO dfs.StateChange: BLOCK* NameSystem.heartbeatCheck: lost heartbeat from 0.0.0.0:50077

Here is what I see in the debugger:
FSNamesystem.heartbeats contains 2 identical (same instance) DatanodeDescriptor entries, both have
DatanodeDescriptor.isAlive = false. The heartbeatCheck() correctly detects that there is a dead node in
the list, but removeDatanode() does not delete the node from the heartbeats because it is dead.

Issue Links

• relates to: HADOOP-1312 heartbeat monitor thread goes away