上次搭建HBase环境后，执行登陆服务器时，报下面的错误：

hadoop@gpmaster logs]$ hbase shell

SLF4J: Class path contains multiple SLF4J bindings.
SLF4J: Found binding in [jar:file:/home/hadoop/hbase-1.0.1.1/lib/slf4j-log4j12-1.7.7.jar!/org/slf4j/impl/StaticLoggerBinder.class]
SLF4J: Found binding in [jar:file:/home/hadoop/hadoop-2.6.0/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.
SLF4J: Actual binding is of type [org.slf4j.impl.Log4jLoggerFactory]
2015-06-13 17:27:40,516 WARN [main] util.NativeCodeLoader: Unable to load native-hadoop library for your platform... using builtin-java classes where applicable
HBase Shell; enter 'help<RETURN>' for list of supported commands.
Type "exit<RETURN>" to leave the HBase Shell
Version 1.0.1.1, re1dbf4df30d214fca14908df71d038081577ea46, Sun May 17 12:34:26 PDT 2015


hbase(main):001:0> status
ERROR: org.apache.hadoop.hbase.PleaseHoldException: Master is initializing
at org.apache.hadoop.hbase.master.HMaster.checkInitialized(HMaster.java:1875)
at org.apache.hadoop.hbase.master.MasterRpcServices.getClusterStatus(MasterRpcServices.java:691)
at org.apache.hadoop.hbase.protobuf.generated.MasterProtos$MasterService$2.callBlockingMethod(MasterProtos.java:42406)
at org.apache.hadoop.hbase.ipc.RpcServer.call(RpcServer.java:2031)
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:745)
Here is some help for this command:
Show cluster status. Can be 'summary', 'simple', 'detailed', or 'replication'. The
default is 'summary'. Examples:
hbase> status
hbase> status 'simple'
hbase> status 'summary'
hbase> status 'detailed'
hbase> status 'replication'
hbase> status 'replication', 'source'
hbase> status 'replication', 'sink'

hbase(main):002:0>

经查看日志/home/hadoop/hbase-1.0.1.1/logs/hbase-hadoop-regionserver-gpmaster.log后，

发现关键错误信息：
client.HConnectionManager$HConnectionImplementation: Can''t get connection to ZooKeeper: KeeperErrorCode = ConnectionLoss for /hbase。
根据信息可以判断zk无法连接。执行jps查看zk都正常。查看hbase-site.xml中zk节点配置正常。根据经验，应该是防火墙没有关闭，2181端口无法访问。
执行service iptables stop关闭防火墙，重启hbase。进入hbase shell，执行list:


hbase(main):001:0> list
TABLE
SLF4J: Class path contains multiple SLF4J bindings.
SLF4J: Found binding in [jar:file:/root/hadoop/hbase/lib/slf4j-log4j12-1.6.4.jar!/org/slf4j/impl/StaticLoggerBinder.class]
SLF4J: Found binding in [jar:file:/root/hadoop/hadoop-2.2.0/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.
2014-07-17 14:06:26,013 WARN [main] util.NativeCodeLoader: Unable to load native-hadoop library for your platform... using builtin-java classes where applicable

0 row(s) in 1.0070 seconds

=> []


这样就一切正常了。