[HBASE-23040] region mover gives NullPointerException instead of saying a host isn't in the cluster

• Type: Bug
• Status: Resolved
• Priority: Minor
• Resolution: Fixed
• Affects Version/s: 3.0.0-alpha-1, 2.1.0, 2.2.0, 2.3.0
• Fix Version/s: 3.0.0-alpha-1, 2.3.0, 2.1.7, 2.2.2

Release Note

giving the region mover "unload" command a region server name that isn't recognized by the cluster results in a "I don't know about that host" message instead of a NPE.

set log level to DEBUG if you'd like the region mover to log the set of region server names it got back from the cluster.

• Assignee: Sean Busbey
• Reporter: Sean Busbey
• Created: 18/Sep/19 03:24
• Updated: 19/Sep/19 01:25
• Resolved: 18/Sep/19 15:39

Description

if passed a host that isn't in the cluster we get a NPE

2019-09-17 21:50:45,595 ERROR [pool-2-thread-1] util.RegionMover: Error while unloading regions 
java.lang.NullPointerException: serverName is null
	at org.apache.hbase.thirdparty.com.google.common.base.Preconditions.checkNotNull(Preconditions.java:897)
	at org.apache.hadoop.hbase.client.AsyncRpcRetryingCallerFactory$AdminRequestCallerBuilder.build(AsyncRpcRetryingCallerFactory.java:518)
	at org.apache.hadoop.hbase.client.AsyncRpcRetryingCallerFactory$AdminRequestCallerBuilder.call(AsyncRpcRetryingCallerFactory.java:522)
	at org.apache.hadoop.hbase.client.RawAsyncHBaseAdmin.getRegions(RawAsyncHBaseAdmin.java:842)
	at org.apache.hadoop.hbase.client.AdminOverAsyncAdmin.getRegions(AdminOverAsyncAdmin.java:229)
	at org.apache.hadoop.hbase.util.RegionMover.unloadRegions(RegionMover.java:448)
	at org.apache.hadoop.hbase.util.RegionMover.lambda$unload$1(RegionMover.java:431)
	at java.util.concurrent.FutureTask.run(FutureTask.java:266)
	at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
	at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
	at java.lang.Thread.run(Thread.java:748)

Should instead give some kind of "I don't know what this host is 'foobar.example.com'" and maybe a debug message with what hosts were in the cluster.

Issue Links

• links to: GitHub Pull Request #635