Question

Hbase 启动报错 class org.apache.hadoop.hbase.master.HMaster

ERROR [main] zookeeper.RecoverableZooKeeper: ZooKeeper create failed after 4 attempts
ERROR [main] master.HMasterCommandLine: Master exiting
java.lang.RuntimeException: Failed construction of Master: class org.apache.hadoop.hbase.master.HMaster
at org.apache.hadoop.hbase.master.HMaster.constructMaster(HMaster.java:2785)
at org.apache.hadoop.hbase.master.HMasterCommandLine.startMaster(HMasterCommandLine.java:184)
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:2799)
Caused by: org.apache.zookeeper.KeeperException$ConnectionLossException: KeeperErrorCode = ConnectionLoss for /hbase
at org.apache.zookeeper.KeeperException.create(KeeperException.java:99)
at org.apache.zookeeper.KeeperException.create(KeeperException.java:51)
at org.apache.zookeeper.ZooKeeper.create(ZooKeeper.java:783)
at org.apache.hadoop.hbase.zookeeper.RecoverableZooKeeper.createNonSequential(RecoverableZooKeeper.java:489)
at org.apache.hadoop.hbase.zookeeper.RecoverableZooKeeper.create(RecoverableZooKeeper.java:468)
at org.apache.hadoop.hbase.zookeeper.ZKUtil.createWithParents(ZKUtil.java:1235)
at org.apache.hadoop.hbase.zookeeper.ZKUtil.createWithParents(ZKUtil.java:1213)
at org.apache.hadoop.hbase.zookeeper.ZooKeeperWatcher.createBaseZNodes(ZooKeeperWatcher.java:174)
at org.apache.hadoop.hbase.zookeeper.ZooKeeperWatcher.<init>(ZooKeeperWatcher.java:167)
at org.apache.hadoop.hbase.master.HMaster.<init>(HMaster.java:473)
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.hbase.master.HMaster.constructMaster(HMaster.java:2780)
... 5 more
系统是centos6.5 Hbase 0.96.2 hadoop 2.2 zookeeper 3.4.6
全部是集群安装，hadoop和zookeeper都能正确启动，就Hbase启动报上述错误，纠结了几天了，也没找出原因！

Answer 1

抱歉碰不到机器可能无法确定问题的具体原因，但从你的问题看出你可能走入了一个误区——认为Hbase启动或安装出现问题
从原理上讲，在集群中Zookeeper中会通过投票方式选举出一个Zookeeper为主，其余类似于主的热备
而主Zookeeper会指定Hmaster，并由指定的Hmaster来进行Hbase的操作
现在你的报错是ZooKeeper create failed after 4 attempts（Zookeeper尝试创建并失败4次导致最终无法创建）带来的后果就是你的Hmaster未选举出（并离线），使得你的Hbase无法管理
大概原因可能有两种
一种是因为各机器间无法正常通信导致集群脑裂Zookeeper无法进行选举
或是各主机之间权限不足导致声明Master的短命节点文件无法被创建（可能性较低）
（也许干脆就是集群数量过小无法选举？）
大概是这些可能，我也还在学习阶段无法给出太过明确的答案，不过建议你从集群互相的通讯（包括每个节点上的Zookeeper安装情况以及互信、网络情况来入手考虑一下？我和很多朋友在安装过程中因为各个节点的软件源以及互信以及软件仓库网络配置等问题纠结了很多天，还有些安装包本身是有问题的（文件损坏或是唯独nagios安装包权限为222导致错误），你可以从这方面入手试试