在 CentOS7 上安装 Zookeeper服务

1、创建 /usr/local/services/zookeeper 文件夹：
mkdir -p /usr/local/services/zookeeper

2、进入到 /usr/local/services/zookeeper 目录中：
cd /usr/local/services/zookeeper

3、下载 zookeeper-3.4.9.tar.gz：
wget https://archive.apache.org/dist/zookeeper/zookeeper-3.4.9/zookeeper-3.4.9.tar.gz

4、解压缩 zookeeper-3.4.9.tar.gz：
tar -zxvf zookeeper-3.4.9.tar.gz

5、进入到 /usr/local/services/zookeeper/zookeeper-3.4.9/conf 目录中：
cd zookeeper-3.4.9/conf/

6、复制 zoo_sample.cfg 文件的并命名为为 zoo.cfg：
cp zoo_sample.cfg zoo.cfg

7、用 vim 打开 zoo.cfg 文件并修改其内容为如下：

# The number of milliseconds of each tick

# zookeeper 定义的基准时间间隔，单位：毫秒
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=/tmp/zookeeper

# 数据文件夹
dataDir=/usr/local/services/zookeeper/zookeeper-3.4.9/data

# 日志文件夹
dataLogDir=/usr/local/services/zookeeper/zookeeper-3.4.9/logs

# the port at which the clients will connect
# 客户端访问 zookeeper 的端口号
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

8、保存并关闭 zoo.cfg 文件:

9、进入到 /usr/local/services/zookeeper/zookeeper-3.4.9/bin 目录中：
cd ../bin/

10、用 vim 打开 /etc/ 目录下的配置文件 profile：
vim /etc/profile
并在其尾部追加如下内容：

#idea - zookeeper-3.4.9 config start - 2017-12-09
export ZOOKEEPER_HOME=/usr/local/services/zookeeper/zookeeper-3.4.9/
export PATH=$ZOOKEEPER_HOME/bin:$PATH
export PATH
#idea - zookeeper-3.4.9 config end - 2017-12-09

11、使 /etc/ 目录下的 profile 文件即可生效：
source /etc/profile

12、启动 zookeeper 服务：
zkServer.sh start
如打印如下信息则表明启动成功：
ZooKeeper JMX enabled by default
Using config: /usr/local/services/zookeeper/zookeeper-3.4.9/bin/../conf/zoo.cfg
Starting zookeeper ... STARTED

13、查询 zookeeper 状态：
zkServer.sh status

14、关闭 zookeeper 服务：
zkServer.sh stop
如打印如下信息则表明成功关闭：
ZooKeeper JMX enabled by default
Using config: /usr/local/services/zookeeper/zookeeper-3.4.9/bin/../conf/zoo.cfg
Stopping zookeeper ... STOPPED

15、重启 zookeeper 服务：
zkServer.sh restart
如打印如下信息则表明重启成功：
ZooKeeper JMX enabled by default
Using config: /usr/local/services/zookeeper/zookeeper-3.4.9/bin/../conf/zoo.cfg
ZooKeeper JMX enabled by default
Using config: /usr/local/services/zookeeper/zookeeper-3.4.9/bin/../conf/zoo.cfg
Stopping zookeeper ... STOPPED
ZooKeeper JMX enabled by default
Using config: /usr/local/services/zookeeper/zookeeper-3.4.9/bin/../conf/zoo.cfg

Starting zookeeper ... STARTED

实际操作如下：

 集群配置：