[HDFS-11932] BPServiceActor thread name is not correctly set

• Type: Bug
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Fix Version/s: 2.9.0, 3.0.0-alpha4, 2.8.2
• Component/s: hdfs
• Hadoop Flags: Reviewed
• Assignee: Chen Liang
• Reporter: Chen Liang
• Created: 05/Jun/17 22:36
• Updated: 24/Apr/18 20:52
• Resolved: 06/Jun/17 20:53

Description

When running unit tests (e.g. TestJMXGet), we often get this following exception, although the tests still passed:

WARN  datanode.DataNode (BPOfferService.java:getBlockPoolId(192)) - Block pool ID needed, but service not yet registered with NN
java.lang.Exception: trace 
at org.apache.hadoop.hdfs.server.datanode.BPOfferService.getBlockPoolId(BPOfferService.java:192) at org.apache.hadoop.hdfs.server.datanode.BPServiceActor.formatThreadName(BPServiceActor.java:556) at org.apache.hadoop.hdfs.server.datanode.BPServiceActor.start(BPServiceActor.java:544) at 
...

It seems that, although this does not affect normal operations, this is causing the thread name of BPServiceActor not correctly set as desired. More specifically,:

 bpThread = new Thread(this, formatThreadName("heartbeating", nnAddr));
 bpThread.setDaemon(true); // needed for JUnit testing
 bpThread.start();

The first line tries to call formatThreadName to get format a thread name, and formatThreadName is reading the value of BPOfferService#bpNSInfo. However this value is set only after the thread started (the third line above). So we get exception in the first line for reading non-existing value.