Linux巩固记录（6） Hbase环境准备-zookeeper安装
Hbase是运行在hadoop之上，所以请参考第3篇文章搭建好一个master，两个slave的hadoop环境，我采用的版本为hadoop2.7.4
不了解Hbase的同学可以参考下这篇文章，分析得相当深刻，感谢作者 http://blog.csdn.net/u010270403/article/details/51648462
为啥在安装Hbase前需要安装zookeeper？
1，hbase regionserver 向zookeeper注册，提供hbase regionserver状态信息（是否在线）
2，hmaster启动时候会将hbase 系统表-ROOT- 加载到 zookeeper cluster，通过zookeeper cluster可以获取当前系统表.META.的存储所对应的regionserver信息。
注意：zookeeper集群节点最少3台，这样才能满足选举规则，少数服从多数
忘了讲一个问题
集群中，所有节点的时间同步非常重要，所以要将所有节点的时间设置为一样，
当然，手动设置时间肯定不行，需要用到ntp来自动同步
#设置时区为上海
cp /usr/share/zoneinfo/Asia/Shanghai /etc/localtime
#安装ntp
yum -y install ntp
# 同步时间
ntpdate pool.ntp.org
#确认时间是否正确
date
#写回bios，防止重启后失效
hwclock -w
现在master节点上配置，配置好后复制到两个slave节点就好了
wget http://mirror.bit.edu.cn/apache/zookeeper/current/zookeeper-3.4.10.tar.gz
tar -zxvf zookeeper-3.4.10.tar.gz
#进入conf目录
cp -p zoo_sample.cfg zoo.cfg
#编辑cfg文件
vi zoo.cfg
#内容修改为如下
# The number of milliseconds of each tick
tickTime=2000
# The number of ticks that the initial
# synchronization phase can take
initLimit=10
# The number of ticks that can pass between
# sending a request and getting an acknowledgement
syncLimit=5
# the directory where the snapshot is stored.
# do not use /tmp for storage, /tmp here is just
# example sakes.
dataDir=/home/dataDir/zookeeper
#事物日志的存储路径,不配置会产生性能问题
dataLogDir=/home/dataDir/zookeeperDataLog
# the port at which the clients will connect clientPort=2181 # the maximum number of client connections. # increase this if you need to handle more clients #maxClientCnxns=60 # # Be sure to read the maintenance section of the # administrator guide before turning on autopurge. # # http://zookeeper.apache.org/doc/current/zookeeperAdmin.html#sc_maintenance # # The number of snapshots to retain in dataDir autopurge.snapRetainCount=3 # Purge task interval in hours # Set to "0" to disable auto purge feature autopurge.purgeInterval=1 server.1=master:2888:3888 server.2=slave1:2888:3888 server.3=slave2:2888:3888
#所有节点
mkdir -p /home/dataDir/zookeeper
#master
echo "1" > /home/dataDir/zookeeper/myid
#slave1
echo "2" > /home/dataDir/zookeeper/myid
#slave2
echo "3" > /home/dataDir/zookeeper/myid
#启动
/home/zookeeper-3.4.10/bin/zkServer.sh start /home/zookeeper-3.4.10/conf/zoo.cfg
#状态查看
[root@master conf]# /home/zookeeper-3.4.10/bin/zkServer.sh status
ZooKeeper JMX enabled by default
Using config: /home/zookeeper-3.4.10/bin/../conf/zoo.cfg
Mode: follower
[root@master conf]#
#如果启动失败，查看日志
less zookeeper.out
#停止服务
[root@master conf]# /home/zookeeper-3.4.10/bin/zkServer.sh stop
ZooKeeper JMX enabled by default
Using config: /home/zookeeper-3.4.10/bin/../conf/zoo.cfg Stopping zookeeper ... STOPPED
[root@master conf]# jps
3589 Jps
[root@master conf]#
找到leader节点，并停掉，你会发现刚开始为follower的某个节点又变为leader了
至此zookeeper配置完成
发现了一篇详细介绍zookeeper的系列好文 http://www.cnblogs.com/sunddenly/category/620563.html
