[HADOOP-1312] heartbeat monitor thread goes away

• Type: Bug
• Status: Closed
• Priority: Blocker
• Resolution: Fixed
• Fix Version/s: 0.13.0
• Assignee: Dhruba Borthakur
• Reporter: Dhruba Borthakur
• Created: 01/May/07 23:13
• Updated: 08/Jul/09 16:42
• Resolved: 02/May/07 21:37

Description

The heartbeat monitor thread encounters a ConcurrentModificationException while iterating over the "heartbeats" data structure. This occurs when the namenode was getting restarted. There are actuallt two bugs here:

1. The Heartbeat Monitor thread needs to catch Exceptions and continue, instead of exiting.
2. The heartbeats data structures is protected by the heartbeats lock. The registerDatanode() method invokes removeDatanode() without acquiring the heartbeats monitor lock. This causes the ConcurrentModificationException.

Issue Links

• is related to: HADOOP-1255 Name-node falls into infinite loop trying to remove a dead node.