[MAPREDUCE-4233] NPE can happen in RMNMNodeInfo.

• Type: Bug
• Status: Closed
• Priority: Critical
• Resolution: Fixed
• Affects Version/s: 0.23.3
• Fix Version/s: 0.23.3, 2.0.2-alpha
• Target Version/s: 0.23.3
• Assignee: Robert Joseph Evans
• Reporter: Robert Joseph Evans
• Created: 08/May/12 16:29
• Updated: 07/Sep/12 21:03
• Resolved: 11/May/12 20:28

Description

Caused by: java.lang.NullPointerException
        at org.apache.hadoop.yarn.server.resourcemanager.RMNMInfo.getLiveNodeManagers(RMNMInfo.java:96)
        at sun.reflect.GeneratedMethodAccessor50.invoke(Unknown Source)
        at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
        at java.lang.reflect.Method.invoke(Method.java:597)
        at com.sun.jmx.mbeanserver.StandardMBeanIntrospector.invokeM2(StandardMBeanIntrospector.java:93)
        at com.sun.jmx.mbeanserver.StandardMBeanIntrospector.invokeM2(StandardMBeanIntrospector.java:27)
        at com.sun.jmx.mbeanserver.MBeanIntrospector.invokeM(MBeanIntrospector.java:208)
        at com.sun.jmx.mbeanserver.PerInterface.getAttribute(PerInterface.java:65)
        at com.sun.jmx.mbeanserver.MBeanSupport.getAttribute(MBeanSupport.java:216)
        at javax.management.StandardMBean.getAttribute(StandardMBean.java:358)
        at com.sun.jmx.interceptor.DefaultMBeanServerInterceptor.getAttribute(DefaultMBeanServerInterceptor.java:666)

Looks like rmcontext.getRMNodes() is not kept in sync with scheduler.getNodeReport(), so that the report can be null even though the context still knowns about the node.

The simple fix is to add in a null check.