启动Hbase时，发现2个RegionServer启动失败，查看日志错误如下：
2017-03-12 21:42:00,527 INFO [regionserver/kf-app1/172.21.3.60:60020] regionserver.HRegionServer: reportForDuty to master=xardc1,60000,1489249767025 with port=60020, startcode=1489326118325 2017-03-12 21:42:00,712 FATAL [regionserver/kf-app1/172.21.3.60:60020] regionserver.HRegionServer: Master rejected startup because clock is out of sync org.apache.hadoop.hbase.ClockOutOfSyncException: org.apache.hadoop.hbase.ClockOutOfSyncException: Server kf-app1,60020,1489326118325 has been rejected; Reported time is too far out of sync with master. Time difference of 163869ms > max allowed of 30000ms at org.apache.hadoop.hbase.master.ServerManager.checkClockSkew(ServerManager.java:357) at org.apache.hadoop.hbase.master.ServerManager.regionServerStartup(ServerManager.java:250) at org.apache.hadoop.hbase.master.MasterRpcServices.regionServerStartup(MasterRpcServices.java:307) at org.apache.hadoop.hbase.protobuf.generated.RegionServerStatusProtos$RegionServerStatusService$2.callBlockingMethod(RegionServerStatusProtos.java:7910) at org.apache.hadoop.hbase.ipc.RpcServer.call(RpcServer.java:2034) at org.apache.hadoop.hbase.ipc.CallRunner.run(CallRunner.java:107) at org.apache.hadoop.hbase.ipc.RpcExecutor.consumerLoop(RpcExecutor.java:130) at org.apache.hadoop.hbase.ipc.RpcExecutor$1.run(RpcExecutor.java:107) at java.lang.Thread.run(Thread.java:724) at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method) at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:57) at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45) at java.lang.reflect.Constructor.newInstance(Constructor.java:526) at org.apache.hadoop.ipc.RemoteException.instantiateException(RemoteException.java:106) at org.apache.hadoop.ipc.RemoteException.unwrapRemoteException(RemoteException.java:95) at org.apache.hadoop.hbase.protobuf.ProtobufUtil.getRemoteException(ProtobufUtil.java:328) at org.apache.hadoop.hbase.regionserver.HRegionServer.reportForDuty(HRegionServer.java:2154) at org.apache.hadoop.hbase.regionserver.HRegionServer.run(HRegionServer.java:847) at java.lang.Thread.run(Thread.java:724) Caused by: org.apache.hadoop.hbase.ipc.RemoteWithExtrasException(org.apache.hadoop.hbase.ClockOutOfSyncException): org.apache.hadoop.hbase.ClockOutOfSyncException: Server kf-app1,60020,1489326118325 has been rejected; Reported time is too far out of sync with master. Time difference of 163869ms > max allowed of 30000ms at org.apache.hadoop.hbase.master.ServerManager.checkClockSkew(ServerManager.java:357) at org.apache.hadoop.hbase.master.ServerManager.regionServerStartup(ServerManager.java:250) at org.apache.hadoop.hbase.master.MasterRpcServices.regionServerStartup(MasterRpcServices.java:307) at org.apache.hadoop.hbase.protobuf.generated.RegionServerStatusProtos$RegionServerStatusService$2.callBlockingMethod(RegionServerStatusProtos.java:7910) at org.apache.hadoop.hbase.ipc.RpcServer.call(RpcServer.java:2034) at org.apache.hadoop.hbase.ipc.CallRunner.run(CallRunner.java:107) at org.apache.hadoop.hbase.ipc.RpcExecutor.consumerLoop(RpcExecutor.java:130) at org.apache.hadoop.hbase.ipc.RpcExecutor$1.run(RpcExecutor.java:107) at java.lang.Thread.run(Thread.java:724) at org.apache.hadoop.hbase.ipc.RpcClientImpl.call(RpcClientImpl.java:1219) at org.apache.hadoop.hbase.ipc.AbstractRpcClient.callBlockingMethod(AbstractRpcClient.java:216) at org.apache.hadoop.hbase.ipc.AbstractRpcClient$BlockingRpcChannelImplementation.callBlockingMethod(AbstractRpcClient.java:300) at org.apache.hadoop.hbase.protobuf.generated.RegionServerStatusProtos$RegionServerStatusService$BlockingStub.regionServerStartup(RegionServerStatusProtos.java:8277) at org.apache.hadoop.hbase.regionserver.HRegionServer.reportForDuty(HRegionServer.java:2152) ... 2 more 2017-03-12 21:42:00,715 FATAL [regionserver/kf-app1/172.21.3.60:60020] regionserver.HRegionServer: ABORTING region server kf-app1,60020,1489326118325: Unhandled: org.apache.hadoop.hbase.ClockOutOfSyncException: Server kf-app1,60020,1489326118325 has been rejected; Reported time is too far out of sync with master. Time difference of 163869ms > max allowed of 30000ms at org.apache.hadoop.hbase.master.ServerManager.checkClockSkew(ServerManager.java:357) at org.apache.hadoop.hbase.master.ServerManager.regionServerStartup(ServerManager.java:250) at org.apache.hadoop.hbase.master.MasterRpcServices.regionServerStartup(MasterRpcServices.java:307) at org.apache.hadoop.hbase.protobuf.generated.RegionServerStatusProtos$RegionServerStatusService$2.callBlockingMethod(RegionServerStatusProtos.java:7910) at org.apache.hadoop.hbase.ipc.RpcServer.call(RpcServer.java:2034) at org.apache.hadoop.hbase.ipc.CallRunner.run(CallRunner.java:107) at org.apache.hadoop.hbase.ipc.RpcExecutor.consumerLoop(RpcExecutor.java:130) at org.apache.hadoop.hbase.ipc.RpcExecutor$1.run(RpcExecutor.java:107) at java.lang.Thread.run(Thread.java:724) org.apache.hadoop.hbase.ClockOutOfSyncException: org.apache.hadoop.hbase.ClockOutOfSyncException: Server kf-app1,60020,1489326118325 has been rejected; Reported time is too far out of sync with master. Time difference of 163869ms > max allowed of 30000ms at org.apache.hadoop.hbase.master.ServerManager.checkClockSkew(ServerManager.java:357) at org.apache.hadoop.hbase.master.ServerManager.regionServerStartup(ServerManager.java:250) at org.apache.hadoop.hbase.master.MasterRpcServices.regionServerStartup(MasterRpcServices.java:307) at org.apache.hadoop.hbase.protobuf.generated.RegionServerStatusProtos$RegionServerStatusService$2.callBlockingMethod(RegionServerStatusProtos.java:7910) at org.apache.hadoop.hbase.ipc.RpcServer.call(RpcServer.java:2034) at org.apache.hadoop.hbase.ipc.CallRunner.run(CallRunner.java:107) at org.apache.hadoop.hbase.ipc.RpcExecutor.consumerLoop(RpcExecutor.java:130) at org.apache.hadoop.hbase.ipc.RpcExecutor$1.run(RpcExecutor.java:107) at java.lang.Thread.run(Thread.java:724) at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method) at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:57) at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45) at java.lang.reflect.Constructor.newInstance(Constructor.java:526) at org.apache.hadoop.ipc.RemoteException.instantiateException(RemoteException.java:106) at org.apache.hadoop.ipc.RemoteException.unwrapRemoteException(RemoteException.java:95) at org.apache.hadoop.hbase.protobuf.ProtobufUtil.getRemoteException(ProtobufUtil.java:328) at org.apache.hadoop.hbase.regionserver.HRegionServer.reportForDuty(HRegionServer.java:2154) at org.apache.hadoop.hbase.regionserver.HRegionServer.run(HRegionServer.java:847) at java.lang.Thread.run(Thread.java:724) Caused by: org.apache.hadoop.hbase.ipc.RemoteWithExtrasException(org.apache.hadoop.hbase.ClockOutOfSyncException): org.apache.hadoop.hbase.ClockOutOfSyncException: Server kf-app1,60020,1489326118325 has been rejected; Reported time is too far out of sync with master. Time difference of 163869ms > max allowed of 30000ms at org.apache.hadoop.hbase.master.ServerManager.checkClockSkew(ServerManager.java:357) at org.apache.hadoop.hbase.master.ServerManager.regionServerStartup(ServerManager.java:250) at org.apache.hadoop.hbase.master.MasterRpcServices.regionServerStartup(MasterRpcServices.java:307) at org.apache.hadoop.hbase.protobuf.generated.RegionServerStatusProtos$RegionServerStatusService$2.callBlockingMethod(RegionServerStatusProtos.java:7910) at org.apache.hadoop.hbase.ipc.RpcServer.call(RpcServer.java:2034) at org.apache.hadoop.hbase.ipc.CallRunner.run(CallRunner.java:107) at org.apache.hadoop.hbase.ipc.RpcExecutor.consumerLoop(RpcExecutor.java:130) at org.apache.hadoop.hbase.ipc.RpcExecutor$1.run(RpcExecutor.java:107) 查看Master主机和RegionServer主机时间，如下：RegionServer：
date Sun Mar 12 21:43:58 CST 2017
Master：
date
Sun Mar 12 21:41:17 CST 2017
由错误可以看出2台主机间的时间误差超过30000ms，Rs将启动失败。
