[HADOOP-3065] Namenode does not process block report if the rack-location script is not provided on namenode

• Type: Bug
• Status: Closed
• Priority: Blocker
• Resolution: Fixed
• Fix Version/s: 0.17.0
• Assignee: Devaraj Das
• Reporter: Dhruba Borthakur
• Created: 21/Mar/08 19:14
• Updated: 08/Jul/09 16:42
• Resolved: 27/Mar/08 21:23

Description

Per HADOOP-1985, If the namenode does not have a dnsToSwicthMapping specified, it does not process block reports from datanode(s). In the ResolutionMonitor, we have the following piece of code:

List<String> rName = dnsToSwitchMapping.resolve(dnHosts);
if (rName == null)

{ continue; }

Instead, we should probably set "DEFAULT RACK" for this datanode.

Also, when a processBlockRepont command is dropped by the namenode, it should log a message to facilitate debugging. The code in FSNamesystem.processReport could be something like this:

if (node.getNetworkLocation().equals(NetworkTopology.UNRESOLVED))

{ LOG.info("Ignoring block report from " + nodeID.getName() + " because rack location for this datanode is still to be resolved."); return null; //drop the block report if the dn hasn't been resolved }