Bug: Deflake TestRSGroupsBasics#testClearDeadServers
Status: Resolved | Priority: Major | Resolution: Fixed
Created: 01/Jun/20 01:48
Affects Version/s: 1.7.0

Ran into this on our internal forks based on branch-1. It also applies to branch-2 but not master because the code has been re-implemented without co-proc due to HBASE-22514

Running into this exception in the test run..

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org.apache.hadoop.hbase.constraint.ConstraintException: The set of servers to remove cannot be null or empty.&#10;	at org.apache.hadoop.hbase.rsgroup.RSGroupAdminServer.removeServers(RSGroupAdminServer.java:391)&#10;	at org.apache.hadoop.hbase.rsgroup.RSGroupAdminEndpoint.postClearDeadServers(RSGroupAdminEndpoint.java:1175)&#10;	at org.apache.hadoop.hbase.master.MasterCoprocessorHost$104.call(MasterCoprocessorHost.java:1251)&#10;	at org.apache.hadoop.hbase.master.MasterCoprocessorHost.execOperation(MasterCoprocessorHost.java:1507)&#10;	at org.apache.hadoop.hbase.master.MasterCoprocessorHost.postClearDeadServers(MasterCoprocessorHost.java:1247)&#10;	at org.apache.hadoop.hbase.master.MasterRpcServices.clearDeadServers(MasterRpcServices.java:1167)&#10;	at org.apache.hadoop.hbase.protobuf.generated.MasterProtos$MasterService$2.callBlockingMethod(MasterProtos.java)&#10;	at org.apache.hadoop.hbase.ipc.RpcServer.call(RpcServer.java:2421)&#10;	at org.apache.hadoop.hbase.ipc.CallRunner.run(CallRunner.java:124)&#10;	at org.apache.hadoop.hbase.ipc.RpcExecutor$Handler.run(RpcExecutor.java:311)&#10;	at org.apache.hadoop.hbase.ipc.RpcExecutor$Handler.run(RpcExecutor.java:291)&#10;" type="org.apache.hadoop.hbase.constraint.ConstraintException">org.apache.hadoop.hbase.constraint.ConstraintException: 
org.apache.hadoop.hbase.constraint.ConstraintException: The set of servers to remove cannot be null or empty.
	at org.apache.hadoop.hbase.rsgroup.RSGroupAdminServer.removeServers(RSGroupAdminServer.java:391)
	at org.apache.hadoop.hbase.rsgroup.RSGroupAdminEndpoint.postClearDeadServers(RSGroupAdminEndpoint.java:1175)
	at org.apache.hadoop.hbase.master.MasterCoprocessorHost$104.call(MasterCoprocessorHost.java:1251)
	at org.apache.hadoop.hbase.master.MasterCoprocessorHost.execOperation(MasterCoprocessorHost.java:1507)
	at org.apache.hadoop.hbase.master.MasterCoprocessorHost.postClearDeadServers(MasterCoprocessorHost.java:1247)
	at org.apache.hadoop.hbase.master.MasterRpcServices.clearDeadServers(MasterRpcServices.java:1167)
	at org.apache.hadoop.hbase.protobuf.generated.MasterProtos$MasterService$2.callBlockingMethod(MasterProtos.java)
	at org.apache.hadoop.hbase.ipc.RpcServer.call(RpcServer.java:2421)
	at org.apache.hadoop.hbase.ipc.CallRunner.run(CallRunner.java:124)
	at org.apache.hadoop.hbase.ipc.RpcExecutor$Handler.run(RpcExecutor.java:311)
	at org.apache.hadoop.hbase.ipc.RpcExecutor$Handler.run(RpcExecutor.java:291)

	at org.apache.hadoop.hbase.rsgroup.TestRSGroupsBasics.testClearDeadServers(TestRSGroupsBasics.java:215)
Caused by: org.apache.hadoop.hbase.ipc.RemoteWithExtrasException: 
org.apache.hadoop.hbase.constraint.ConstraintException: The set of servers to remove cannot be null or empty.
	at org.apache.hadoop.hbase.rsgroup.RSGroupAdminServer.removeServers(RSGroupAdminServer.java:391)
	at org.apache.hadoop.hbase.rsgroup.RSGroupAdminEndpoint.postClearDeadServers(RSGroupAdminEndpoint.java:1175)
	at org.apache.hadoop.hbase.master.MasterCoprocessorHost$104.call(MasterCoprocessorHost.java:1251)
	at org.apache.hadoop.hbase.master.MasterCoprocessorHost.execOperation(MasterCoprocessorHost.java:1507)
	at org.apache.hadoop.hbase.master.MasterCoprocessorHost.postClearDeadServers(MasterCoprocessorHost.java:1247)
	at org.apache.hadoop.hbase.master.MasterRpcServices.clearDeadServers(MasterRpcServices.java:1167)
	at org.apache.hadoop.hbase.protobuf.generated.MasterProtos$MasterService$2.callBlockingMethod(MasterProtos.java)
	at org.apache.hadoop.hbase.ipc.RpcServer.call(RpcServer.java:2421)
	at org.apache.hadoop.hbase.ipc.CallRunner.run(CallRunner.java:124)
	at org.apache.hadoop.hbase.ipc.RpcExecutor$Handler.run(RpcExecutor.java:311)
	at org.apache.hadoop.hbase.ipc.RpcExecutor$Handler.run(RpcExecutor.java:291)
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