HBase启动后HMaster会自动关闭

在开启HBase集群之后，就出现了HMaster在启动后几秒内自动关闭，HRegionServer运行正常。查看log日志发现这样的错误提示：

java.net.ConnectException: Call From hadoop102/192.168.1.102 to hadoop102:8020 failed on connection exception: java.net.ConnectException: 拒绝连接; For more details see:  http://wiki.apache.org/hadoop/ConnectionRefused
    at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
    at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62)
    at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
    at java.lang.reflect.Constructor.newInstance(Constructor.java:422)
    at org.apache.hadoop.net.NetUtils.wrapWithMessage(NetUtils.java:792)
    at org.apache.hadoop.net.NetUtils.wrapException(NetUtils.java:732)
    at org.apache.hadoop.ipc.Client.call(Client.java:1479)
    at org.apache.hadoop.ipc.Client.call(Client.java:1412)
    at org.apache.hadoop.ipc.ProtobufRpcEngine$Invoker.invoke(ProtobufRpcEngine.java:229)
    at com.sun.proxy.$Proxy16.setSafeMode(Unknown Source)
    at org.apache.hadoop.hdfs.protocolPB.ClientNamenodeProtocolTranslatorPB.setSafeMode(ClientNamenodeProtocolTranslatorPB.java:666)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:497)
    at org.apache.hadoop.io.retry.RetryInvocationHandler.invokeMethod(RetryInvocationHandler.java:191)
    at org.apache.hadoop.io.retry.RetryInvocationHandler.invoke(RetryInvocationHandler.java:102)
    at com.sun.proxy.$Proxy17.setSafeMode(Unknown Source)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:497)
    at org.apache.hadoop.hbase.fs.HFileSystem$1.invoke(HFileSystem.java:302)
    at com.sun.proxy.$Proxy18.setSafeMode(Unknown Source)
    at org.apache.hadoop.hdfs.DFSClient.setSafeMode(DFSClient.java:2596)
    at org.apache.hadoop.hdfs.DistributedFileSystem.setSafeMode(DistributedFileSystem.java:1223)
    at org.apache.hadoop.hdfs.DistributedFileSystem.setSafeMode(DistributedFileSystem.java:1207)
    at org.apache.hadoop.hbase.util.FSUtils.isInSafeMode(FSUtils.java:525)
    at org.apache.hadoop.hbase.util.FSUtils.waitOnSafeMode(FSUtils.java:971)
    at org.apache.hadoop.hbase.master.MasterFileSystem.checkRootDir(MasterFileSystem.java:428)
    at org.apache.hadoop.hbase.master.MasterFileSystem.createInitialFileSystemLayout(MasterFileSystem.java:152)
    at org.apache.hadoop.hbase.master.MasterFileSystem.(MasterFileSystem.java:127)
    at org.apache.hadoop.hbase.master.HMaster.finishActiveMasterInitialization(HMaster.java:714)
    at org.apache.hadoop.hbase.master.HMaster.access$600(HMaster.java:198)
    at org.apache.hadoop.hbase.master.HMaster$2.run(HMaster.java:1868)
    at java.lang.Thread.run(Thread.java:745)
Caused by: java.net.ConnectException: 拒绝连接
    at sun.nio.ch.SocketChannelImpl.checkConnect(Native Method)
    at sun.nio.ch.SocketChannelImpl.finishConnect(SocketChannelImpl.java:717)
    at org.apache.hadoop.net.SocketIOWithTimeout.connect(SocketIOWithTimeout.java:206)
    at org.apache.hadoop.net.NetUtils.connect(NetUtils.java:531)
    at org.apache.hadoop.net.NetUtils.connect(NetUtils.java:495)
    at org.apache.hadoop.ipc.Client$Connection.setupConnection(Client.java:614)
    at org.apache.hadoop.ipc.Client$Connection.setupIOstreams(Client.java:712)
    at org.apache.hadoop.ipc.Client$Connection.access$2900(Client.java:375)
    at org.apache.hadoop.ipc.Client.getConnection(Client.java:1528)
    at org.apache.hadoop.ipc.Client.call(Client.java:1451)
    ... 29 more

错误分析：
从上面的日志可以看出，在连接hadoop102:8020时出错，我们知道8020是hdfs的默认端口，但是我们在配置Hadoop集群时在core-site.xml中将hdfs的默认端口改为了9000:

<property>
    <name>fs.defaultFSname>
    <value>hdfs://hadoop102:9000value>
property>

但是我们的在Hbase-site.xml文件：

 
<property>     
        <name>hbase.rootdirname>     
        <value>hdfs://hadoop102:8020/hbasevalue>   
property>

不难发现，这时候我们并没有指定hdfs的端口，因此，在hbase启动后它会去找hdfs的默认端口8020，于是就导致了上面的错误。

解决方案：
在配置hbase.rootdir属性时显式指定hdfs的端口为9000，配置文件修改如下：

    <property>     
            <name>hbase.rootdirname>     
            <value>hdfs://hadoop102:9000/hbasevalue>   
    property>

之后进行重启操作即可。