通过tarball形式安装HBASE Cluster（CDH5.0.2）——Hadoop NameNode HA 切换引起的Hbase错误，以及Hbase如何基于NameNode的HA进行配置
配置HBASE的时候一开始按照cdh网站上的说明，hbase.rootdir的值设置使用的是基于Hadoop Namenode HA的nameservice
<property>
<name>hbase.rootdir</name>
<value>hdfs://hbasecluster/hbase</value>
</property>
配置后，使用start-hbase.sh启动，只有位于bakup-masters文件中的HMaster能启动，hbase配置的位于Hadoop DateNode上的RegionServer都启动失败，所报错误为连接hdfs:/hbasecluster:8020失败（），当时网上搜索未果，只好改成单机模式：
<property>
<name>hbase.rootdir</name>
<value>hdfs://nn1:8020/hbase</value>
</property>
此时，hbase可以启动成功，hbase shell测试，远程java程序测试皆通过。逐渐地我就忘记这个配置遗留问题了，结果昨天心血来潮又测试了一下Namenode的HA切换，这个倒是成功了没有问题。可是在测试java程序访问hbase发现失败了，到服务器上看主节点zk1上的HMaster进程没有了，zk2，zk3上的HMaster进程虽然有也不能链接，于zk1上重新启动hbase集群
stop-hbase.sh
start-hbase.sh jps
随后用jps查看，发现HMaster进程很快消失，查看log发现，报如下错误：
2014-07-24 08:51:47,023 FATAL [master:zk1:60000] master.HMaster: Unhandled exception. Starting shutdown.
org.apache.hadoop.ipc.RemoteException(org.apache.hadoop.ipc.StandbyException): Operation category READ is not supported in state standby
at org.apache.hadoop.hdfs.server.namenode.ha.StandbyState.checkOperation(StandbyState.java:87)
at org.apache.hadoop.hdfs.server.namenode.NameNode$NameNodeHAContext.checkOperation(NameNode.java:1565)
at org.apache.hadoop.hdfs.server.namenode.FSNamesystem.checkOperation(FSNamesystem.java:1183)
at org.apache.hadoop.hdfs.server.namenode.FSNamesystem.getFileInfo(FSNamesystem.java:3492)
at org.apache.hadoop.hdfs.server.namenode.NameNodeRpcServer.getFileInfo(NameNodeRpcServer.java:764)
at org.apache.hadoop.hdfs.protocolPB.ClientNamenodeProtocolServerSideTranslatorPB.getFileInfo(ClientNamenodeProtocolServerSideTranslatorPB.java:764)
at org.apache.hadoop.hdfs.protocol.proto.ClientNamenodeProtocolProtos$ClientNamenodeProtocol$2.callBlockingMethod(ClientNamenodeProtocolProtos.java)
at org.apache.hadoop.ipc.ProtobufRpcEngine$Server$ProtoBufRpcInvoker.call(ProtobufRpcEngine.java:585)
at org.apache.hadoop.ipc.RPC$Server.call(RPC.java:1026)
at org.apache.hadoop.ipc.Server$Handler$1.run(Server.java:1986)
at org.apache.hadoop.ipc.Server$Handler$1.run(Server.java:1982)
at java.security.AccessController.doPrivileged(Native Method)
at javax.security.auth.Subject.doAs(Subject.java:415)
at org.apache.hadoop.security.UserGroupInformation.doAs(UserGroupInformation.java:1548)
at org.apache.hadoop.ipc.Server$Handler.run(Server.java:1980) at org.apache.hadoop.ipc.Client.call(Client.java:1409)
at org.apache.hadoop.ipc.Client.call(Client.java:1362)
at org.apache.hadoop.ipc.ProtobufRpcEngine$Invoker.invoke(ProtobufRpcEngine.java:206)
at com.sun.proxy.$Proxy12.getFileInfo(Unknown Source)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:606)
at org.apache.hadoop.io.retry.RetryInvocationHandler.invokeMethod(RetryInvocationHandler.java:186)
at org.apache.hadoop.io.retry.RetryInvocationHandler.invoke(RetryInvocationHandler.java:102)
at com.sun.proxy.$Proxy12.getFileInfo(Unknown Source)
at org.apache.hadoop.hdfs.protocolPB.ClientNamenodeProtocolTranslatorPB.getFileInfo(ClientNamenodeProtocolTranslatorPB.java:699)
at org.apache.hadoop.hdfs.DFSClient.getFileInfo(DFSClient.java:1757)
at org.apache.hadoop.hdfs.DistributedFileSystem$17.doCall(DistributedFileSystem.java:1124)
at org.apache.hadoop.hdfs.DistributedFileSystem$17.doCall(DistributedFileSystem.java:1120)
at org.apache.hadoop.fs.FileSystemLinkResolver.resolve(FileSystemLinkResolver.java:81)
at org.apache.hadoop.hdfs.DistributedFileSystem.getFileStatus(DistributedFileSystem.java:1120)
at org.apache.hadoop.fs.FileSystem.exists(FileSystem.java:1398)
at org.apache.hadoop.hbase.master.MasterFileSystem.checkRootDir(MasterFileSystem.java:438)
at org.apache.hadoop.hbase.master.MasterFileSystem.createInitialFileSystemLayout(MasterFileSystem.java:146)
at org.apache.hadoop.hbase.master.MasterFileSystem.<init>(MasterFileSystem.java:127)
at org.apache.hadoop.hbase.master.HMaster.finishInitialization(HMaster.java:789)
at org.apache.hadoop.hbase.master.HMaster.run(HMaster.java:606)
at java.lang.Thread.run(Thread.java:745)
2014-07-24 08:51:47,025 INFO [master:zk1:60000] master.HMaster: Aborting
2014-07-24 08:51:47,026 DEBUG [master:zk1:60000] master.HMaster: Stopping service threads
2014-07-24 08:51:47,026 INFO [master:zk1:60000] ipc.RpcServer: Stopping server on 60000
2014-07-24 08:51:47,026 INFO [RpcServer.handler=0,port=60000] ipc.RpcServer: RpcServer.handler=0,port=60000: exiting
2014-07-24 08:51:47,027 INFO [RpcServer.handler=1,port=60000] ipc.RpcServer: RpcServer.handler=1,port=60000: exiting
2014-07-24 08:51:47,027 INFO [RpcServer.handler=3,port=60000] ipc.RpcServer: RpcServer.handler=3,port=60000: exiting
2014-07-24 08:51:47,027 INFO [RpcServer.handler=2,port=60000] ipc.RpcServer: RpcServer.handler=2,port=60000: exiting
2014-07-24 08:51:47,027 INFO [RpcServer.handler=4,port=60000] ipc.RpcServer: RpcServer.handler=4,port=60000: exiting
2014-07-24 08:51:47,027 INFO [RpcServer.handler=5,port=60000] ipc.RpcServer: RpcServer.handler=5,port=60000: exiting
2014-07-24 08:51:47,027 INFO [RpcServer.handler=6,port=60000] ipc.RpcServer: RpcServer.handler=6,port=60000: exiting
2014-07-24 08:51:47,027 INFO [RpcServer.handler=7,port=60000] ipc.RpcServer: RpcServer.handler=7,port=60000: exiting
2014-07-24 08:51:47,027 INFO [RpcServer.handler=8,port=60000] ipc.RpcServer: RpcServer.handler=8,port=60000: exiting
2014-07-24 08:51:47,028 INFO [RpcServer.handler=9,port=60000] ipc.RpcServer: RpcServer.handler=9,port=60000: exiting
2014-07-24 08:51:47,028 INFO [RpcServer.handler=10,port=60000] ipc.RpcServer: RpcServer.handler=10,port=60000: exiting
2014-07-24 08:51:47,028 INFO [RpcServer.handler=11,port=60000] ipc.RpcServer: RpcServer.handler=11,port=60000: exiting
2014-07-24 08:51:47,028 INFO [RpcServer.handler=12,port=60000] ipc.RpcServer: RpcServer.handler=12,port=60000: exiting
2014-07-24 08:51:47,028 INFO [RpcServer.handler=13,port=60000] ipc.RpcServer: RpcServer.handler=13,port=60000: exiting
2014-07-24 08:51:47,028 INFO [RpcServer.handler=14,port=60000] ipc.RpcServer: RpcServer.handler=14,port=60000: exiting
2014-07-24 08:51:47,028 INFO [RpcServer.handler=15,port=60000] ipc.RpcServer: RpcServer.handler=15,port=60000: exiting
2014-07-24 08:51:47,028 INFO [RpcServer.handler=16,port=60000] ipc.RpcServer: RpcServer.handler=16,port=60000: exiting
2014-07-24 08:51:47,029 INFO [RpcServer.handler=17,port=60000] ipc.RpcServer: RpcServer.handler=17,port=60000: exiting
2014-07-24 08:51:47,029 INFO [RpcServer.handler=19,port=60000] ipc.RpcServer: RpcServer.handler=19,port=60000: exiting
2014-07-24 08:51:47,029 INFO [RpcServer.handler=18,port=60000] ipc.RpcServer: RpcServer.handler=18,port=60000: exiting
2014-07-24 08:51:47,029 INFO [RpcServer.handler=20,port=60000] ipc.RpcServer: RpcServer.handler=20,port=60000: exiting
2014-07-24 08:51:47,029 INFO [RpcServer.handler=21,port=60000] ipc.RpcServer: RpcServer.handler=21,port=60000: exiting
2014-07-24 08:51:47,029 INFO [RpcServer.handler=22,port=60000] ipc.RpcServer: RpcServer.handler=22,port=60000: exiting
2014-07-24 08:51:47,029 INFO [RpcServer.handler=24,port=60000] ipc.RpcServer: RpcServer.handler=24,port=60000: exiting
2014-07-24 08:51:47,029 INFO [RpcServer.handler=23,port=60000] ipc.RpcServer: RpcServer.handler=23,port=60000: exiting
2014-07-24 08:51:47,030 INFO [RpcServer.handler=26,port=60000] ipc.RpcServer: RpcServer.handler=26,port=60000: exiting
2014-07-24 08:51:47,030 INFO [RpcServer.handler=27,port=60000] ipc.RpcServer: RpcServer.handler=27,port=60000: exiting
2014-07-24 08:51:47,030 INFO [RpcServer.handler=25,port=60000] ipc.RpcServer: RpcServer.handler=25,port=60000: exiting
2014-07-24 08:51:47,030 INFO [RpcServer.handler=28,port=60000] ipc.RpcServer: RpcServer.handler=28,port=60000: exiting
2014-07-24 08:51:47,030 INFO [RpcServer.handler=29,port=60000] ipc.RpcServer: RpcServer.handler=29,port=60000: exiting
2014-07-24 08:51:47,036 INFO [Replication.RpcServer.handler=0,port=60000] ipc.RpcServer: Replication.RpcServer.handler=0,port=60000: exiting
2014-07-24 08:51:47,036 INFO [Replication.RpcServer.handler=1,port=60000] ipc.RpcServer: Replication.RpcServer.handler=1,port=60000: exiting
2014-07-24 08:51:47,037 INFO [Replication.RpcServer.handler=2,port=60000] ipc.RpcServer: Replication.RpcServer.handler=2,port=60000: exiting
2014-07-24 08:51:47,038 INFO [RpcServer.listener,port=60000] ipc.RpcServer: RpcServer.listener,port=60000: stopping
2014-07-24 08:51:47,039 INFO [master:zk1:60000] master.HMaster: Stopping infoServer
2014-07-24 08:51:47,043 INFO [RpcServer.responder] ipc.RpcServer: RpcServer.responder: stopped
2014-07-24 08:51:47,043 INFO [RpcServer.responder] ipc.RpcServer: RpcServer.responder: stopping
2014-07-24 08:51:47,055 INFO [master:zk1:60000] mortbay.log: Stopped SelectChannelConnector@0.0.0.0:60010
2014-07-24 08:51:47,190 INFO [master:zk1:60000] zookeeper.ZooKeeper: Session: 0x164756c65ba5008e closed
2014-07-24 08:51:47,191 INFO [master:zk1:60000] master.HMaster: HMaster main thread exiting
2014-07-24 08:51:47,191 ERROR [main] master.HMasterCommandLine: Master exiting
java.lang.RuntimeException: HMaster Aborted
at org.apache.hadoop.hbase.master.HMasterCommandLine.startMaster(HMasterCommandLine.java:192)
at org.apache.hadoop.hbase.master.HMasterCommandLine.run(HMasterCommandLine.java:134)
at org.apache.hadoop.util.ToolRunner.run(ToolRunner.java:70)
at org.apache.hadoop.hbase.util.ServerCommandLine.doMain(ServerCommandLine.java:126)
at org.apache.hadoop.hbase.master.HMaster.main(HMaster.java:2789)
2014-07-24 08:51:47,191 INFO [main-EventThread] zookeeper.ClientCnxn: EventThread shut down
仔细看，发现是namenode报的错，检查nn1状态，发现此时nn1处于standby状态，nn2已经处于active状态，突然想起昨天的测试。这激起了我解决这个问题的决心，经过一翻goooooooooooooooogle，终于在hbase官网上的hbase文档中发现了如下几行内容：
2.2.2.2.3. HDFS Client Configuration
Of note, if you have made HDFS client configuration on your Hadoop cluster -- i.e. configuration you want HDFS clients to use as opposed to server-side configurations -- HBase will not see this configuration unless you do one of the following: Add a pointer to your HADOOP_CONF_DIR to the HBASE_CLASSPATH environment variable in hbase-env.sh. Add a copy of hdfs-site.xml (or hadoop-site.xml) or, better, symlinks, under ${HBASE_HOME}/conf, or if only a small set of HDFS client configurations, add them to hbase-site.xml. An example of such an HDFS client configuration is dfs.replication. If for example, you want to run with a replication factor of 5, hbase will create files with the default of 3 unless you do the above to make the configuration available to HBase.
我才用的是方法二，在所有的master节点和regionserver节点上都建立了hdfs-site.xml的符号链接(scp 分发符号连接不行，都变成真实文件了)，hbase.rootdir配置为nameservice方式，再次测试hbase集群启动，成功!
然后测试hadoop namenode切换，hbase没问题了，至此困扰我多日的问题终于解决了。