ubuntu-18.04 安装 zookeeper-3.4.13

本文记录了我安装zookeeper的方法，最后运行了一个单机的实例验证安装。

一、安装JDK

因为zookeeper采用Java编写的，因此咱们须要Java环境才能运行 此处咱们采用open-jdk-8 直接一行命令便可安装

$ sudo apt-get install openjdk-8-jre
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二、下载zookeeper

打开zookeeper官网，能够找到对应的下载地址: archive.apache.org/dist/zookee…

使用wget下载：

$ wget https://archive.apache.org/dist/zookeeper/zookeeper-3.4.13/zookeeper-3.4.13.tar.gz
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三、解压zookeeper

下载下来的文件是压缩文件，所以，咱们须要解压

$ tar -xvf zookeeper-3.4.13.tar.gz
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四、移动解压的文件夹到安装目录

安装目录能够为任意，此处咱们安装在/usr/local/zookeeper/下，所以，将刚才下载解压完成的文件夹移动到/usr/local/zookeeper/

$ mv zookeeper-3.4.13 /usr/local/zookeeper/zookeeper-3.4.13
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五、为zookeeper建立软连接

为了方便之后zookeeper的版本更新，咱们安装zookeeper的时候能够在同级目录下建立一个不带版本号的软连接，而后将其指向带zookeeper的真正目录

即建立一个名为/usr/local/zookeeper/apache-zookeeper的软连接，指向/usr/local/zookeeper/zookeeper-3.4.13，之后更新版本的话，只须要修改软连接的指向，而咱们配置的环境变量都不须要作任何更改

$ ln -s /usr/local/zookeeper/zookeeper-3.4.13 /usr/local/zookeeper/apache-zookeeper
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四、修改PATH

将zookeeper添加到环境变量

$ vim /etc/profile
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新增下面两行

# 此处使用刚刚建立的软连接
export ZK_HOME=/usr/local/zookeeper/apache-zookeeper
export PATH=$ZK_HOME/bin:$PATH
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让刚才修改的path生效

$ source /etc/profile
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此时，zookeeper的安装完成，启动一个单机版的测试一下

五、修改zoo.cfg文件

zookeeper启动时候，会读取conf文件夹下的zoo.cfg做为配置文件，所以，咱们能够将源码提供的示例配置文件复制一个，作一些修改

# 进入配置文件目录
$ cd /usr/local/zookeeper/apache-zookeeper/conf

# 复制示例配置文件
cp zoo_sample.cfg zoo.cfg

# 修改 zoo.cfg 配置文件
vim zoo.cfg
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修改数据存放位置 dataDir=/usr/local/zookeeper/data

# 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.


# 只须要修改此处为zookeeper数据存放位置
dataDir=/usr/local/zookeeper/data
# 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 
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六、开始运行

进入bin目录，执行运行命令(因为刚才设置了zookeeper到环境变量PATH里面，因此，咱们其实能够在任何目录下执行下面的命令)

# 进入bin目录
$ cd /usr/local/zookeeper/apache-zookeeper/bin

# 执行启动命令
$ ./zkServer.sh start

ZooKeeper JMX enabled by default
Using config: /usr/local/zookeeper/apache-zookeeper/bin/../conf/zoo.cfg
Starting zookeeper ... STARTED

# 查看状态
$ ./zkServer.sh status 
ZooKeeper JMX enabled by default
Using config: /usr/local/zookeeper/apache-zookeeper/bin/../conf/zoo.cfg
Mode: standalone
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看到命令行输出运行成功，表明运行成功