[HADOOP-2767] org.apache.hadoop.net.NetworkTopology.InnerNode#getLeaf does not return the last node on a rack when used with an excluded node

• Type: Bug
• Status: Closed
• Priority: Minor
• Resolution: Fixed
• Affects Version/s: 0.15.3
• Fix Version/s: 0.17.0
• Assignee: Hairong Kuang
• Reporter: Mark Butler
• Created: 01/Feb/08 15:58
• Updated: 08/Jul/09 16:42
• Resolved: 07/Feb/08 14:54

Description

I have written some test code that shows NetworkTopology.InnerNode#getLeaf will never return the last node on the rack if it is called with an excludedNode (for example the first node on the rack).

Consequently I suspect that NetworkTopology.chooseRandom() will never returns the last node on the remote rack for the second replica in DFS.

I have some test code that demonstrates this problem at the getLeaf level, although it is necessary to change the visibility of the NetworkTopology.InnerNode, NetworkTopology.InnerNode#getLeaf and NetworkTopology.getNode from private to package default to run the test.

TODO: Demonstrate problem at NetworkTopology.chooseRandom level, then submit candidate fix.