我在三台主机上配置Hadoop 2.2.0 和HBase 0.98.3 (其自带的hadoop common的jar包就是2.2.0版本的)，一台机器为Debian 7.5, 机器名为psyDebian，运行namenode和datanode，另外两台为centos 6.5, 名字分别为centos1和centos2，运行datanode。Hadoop的hdfs运行良好，但在其基础上运行HBase时，刚开始启动良好，但是过一会后HMaster和HRegionServer自动退出。一开始时主节点上jps是这样的：

        5416 NameNode

        5647 SecondaryNameNode

        5505 DataNode

        398 Jps

        32745 HMaster

        32670 HQuorumPeer

等了十几秒后，jps是这样：

        5416 NameNode

        5647 SecondaryNameNode

        5505 DataNode

        423 Jps

        32670 HQuorumPeer

从节点中的HRegionServer也是同样如此。

hbase-hadoop-master-psyDebian.log日志有错误，如下：

2014-07-16 09:57:01,061 WARN  [main-SendThread(centos1:2181)] zookeeper.ClientCnxn: Session 0x0 for server centos1/192.168.1.110:2181, unexpected error, closing socket connection and attempting reconnect

...

2014-07-16 09:57:02,128 WARN  [main] zookeeper.RecoverableZooKeeper: Possibly transient ZooKeeper, quorum=centos1:2181,psyDebian:2181,centos2:2181, exception=org.apache.zookeeper.KeeperException$ConnectionLossException: KeeperErrorCode = ConnectionLoss for /hbase

2014-07-16 09:57:02,129 ERROR [main] zookeeper.RecoverableZooKeeper: ZooKeeper create failed after 4 attempts

2014-07-16 09:57:02,129 ERROR [main] master.HMasterCommandLine: Master exiting

...

java.lang.RuntimeException: Failed construction of Master: class org.apache.hadoop.hbase.master.HMaster

    ...

Caused by: org.apache.zookeeper.KeeperException$ConnectionLossException: KeeperErrorCode = ConnectionLoss for /hbase

貌似是zookeeper有错误，但是我用的是hbase自带的，HBASE_MANAGES_ZK=true已经设置，而且HQuorumPeer进程一直在运行。

在hbase-hadoop-master-psyDebian.out中有个警告：

SLF4J: Class path contains multiple SLF4J bindings.

SLF4J: Found binding in [jar:file:/opt/hbase/lib/slf4j-log4j12-1.7.5.jar!/org/slf4j/impl/StaticLoggerBinder.class]

SLF4J: Found binding in [jar:file:/opt/hadoop/share/hadoop/common/lib/slf4j-log4j12-1.7.5.jar!/org/slf4j/impl/StaticLoggerBinder.class]

SLF4J: See http://www.slf4j.org/codes.html#multiple_bindings for an explanation.

hbase-hadoop-zookeeper-psyDebian.log中只重复如下信息：

2014-07-16 10:05:57,502 INFO  [WorkerReceiver[myid=0]] quorum.FastLeaderElection: Notification: 1 (n.leader), 0x0 (n.zxid), 0x26 (n.round), LEADING (n.state), 1 (n.sid), 0x0 (n.peerEPoch), LOOKING (my state)

在从节点中的hbase-hadoop-regionserver-centos1.log日志如下

2014-07-16 09:57:05,150 ERROR [main] regionserver.HRegionServerCommandLine: Region server exiting

java.lang.RuntimeException: HRegionServer Aborted

从节点hbase-hadoop-hbase-centos1.out居然报了找不到类的错误

Exception in thread "main" java.lang.NoClassDefFoundError: hbase

Caused by: java.lang.ClassNotFoundException: hbase

因为我是刚开始使用Hbase，不太了解源码，所以没法从源码级别找错误。我在网上寻找了四五天的答案，没找到有用的信息。三台机器时间已经同步，防火墙全部关闭，也反复删除临时文件重启多次，依旧HMaster和HRegionServer十几秒后退出。后面是我的关键配置文件：

hadoop下的hdfs-site.xml

<configuration>

    <property>

        <name>dfs.datanode.data.dir</name>

        <value>/home/hadoop/hadoop_tmp/dfs/data</value>

    </property>

    <property>

        <name>dfs.namenode.name.dir</name>

        <value>/home/hadoop/hadoop_tmp/dfs/name</value>

    </property>

    <property>

        <name>dfs.replication</name>

        <value>3</value>

    </property>

</configuration>

core-site.xml

<configuration>

    <property>

        <name>fs.default.name</name>

        <value>hdfs://psyDebian:9000</value>

    </property>

    <property>

        <name>hadoop.tmp.dir</name>

        <value>/home/hadoop/hadoop_tmp</value>

    </property>

</configuration>

slaves

psyDebian

centos1

centos2

hbase下的hbase-site.xml

<configuration>

    <property>

        <name>hbase.rootdir</name>

        <value>hdfs://psyDebian:9000/hbase</value>

    </property>

    <property>

        <name>hbase.cluster.distributed</name>

        <value>true</value>

    </property>

    <property>

        <name>hbase.master</name>

        <value>psyDebian:60000</value>

    </property>

    <property>

        <name>hbase.zookeeper.quorum</name>

        <value>psyDebian,centos1,centos2</value>

    </property>

    <property>

        <name>hbase.zookeeper.property.dataDir</name>

        <value>/home/hadoop/zookeeper_tmp</value>

    </property>

    <property>

        <name>zookeeper.session.timeout</name>

        <value>90000</value>

    </property>

    <property>

        <name>hbase.reginserver.restart.on.zk.expire</name>

        <value>true</value>

    </property>

</configuration>

regionservers

centos1

centos2

hbase

今天运行hadoop程序时发现错误：

failed on connection exception: java.net.ConnectException: Connection refused; For more details see:  http://wiki.apache.org/hadoop/ConnectionRefused

然后根据提示的链接逐项排查错误，将/etc/hosts中的127.0.0.1 psyDebian删除（从节点对应也删除）后程序运行正常。接着尝试运行HBase，没有出现问题！创建表也正常了！

一开始也知道得删除hosts文件中127.0.1.1，但是没想到127.0.0.1 主机名也得删除。就这样，困扰我一个星期左右的问题解决了。