[HDFS-12112] TestBlockManager#testBlockManagerMachinesArray sometimes fails with NPE

• Type: Bug
• Status: Resolved
• Priority: Minor
• Resolution: Fixed
• Affects Version/s: 3.0.0-beta1
• Fix Version/s: 2.9.0, 3.0.0-beta1, 2.8.2

Environment

CDH5.12.0

• Hadoop Flags: Reviewed
• Assignee: Wei-Chiu Chuang
• Reporter: Wei-Chiu Chuang
• Created: 10/Jul/17 19:25
• Updated: 02/Oct/19 17:16
• Resolved: 16/Jul/17 03:50

Description

Found the following error:

java.lang.NullPointerException: null
at org.apache.hadoop.hdfs.server.blockmanagement.TestBlockManager.testBlockManagerMachinesArray(TestBlockManager.java:1202)

The NPE suggests corruptStorageDataNode in the following code snippet could be null.

for(int i=0; i<corruptStorageDataNode.getStorageInfos().length; i++) {

Looking at the code, the test does not wait for file replication to happen, which is why corruptStorageDataNode (the DN of the second replica) is null.