[YARN-1934] Potential NPE in ZKRMStateStore caused by handling Disconnected event from ZK.

• Type: Bug
• Status: Closed
• Priority: Blocker
• Resolution: Fixed
• Affects Version/s: 2.4.0
• Fix Version/s: 2.4.1
• Component/s: resourcemanager
• Target Version/s: 2.4.1
• Hadoop Flags: Reviewed
• Assignee: Karthik Kambatla
• Reporter: Rohith Sharma K S
• Created: 12/Apr/14 07:20
• Updated: 03/Nov/14 18:05
• Resolved: 16/Apr/14 02:07

Description

For ZK disconnected event , zkClient is set to null. It is very much prone to throw NPE.

        case Disconnected:
          LOG.info("ZKRMStateStore Session disconnected");
          oldZkClient = zkClient;
          zkClient = null;
          break;