centos安装zookeeper服务
zookeeper介绍
ZooKeeper 是一个开源的分布式协调服务。它是一个为分布式应用提供一致性服务的软件，分布式应用程序可以基于 Zookeeper 实现诸如数据发布/订阅、负载均衡、命名服务、分布式协调/通知、集群管理、Master 选举、分布式锁和分布式队列等功能。
ZooKeeper 的目标就是封装好复杂易出错的关键服务，将简单易用的接口和性能高效、功能稳定的系统提供给用户。
Zookeeper 保证了如下分布式一致性特性：
顺序一致性
原子性
单一视图
可靠性
实时性（最终一致性）
客户端的读请求可以被集群中的任意一台机器处理，如果读请求在节点上注册了监听器，这个监听器也是由所连接的 zookeeper 机器来处理。对于写请求，这些请求会同时发给其他 zookeeper 机器并且达成一致后，请求才会返回成功。因此，随着 zookeeper 的集群机器增多，读请求的吞吐会提高但是写请求的吞吐会下降。
有序性是 zookeeper 中非常重要的一个特性，所有的更新都是全局有序的，每个更新都有一个唯一的时间戳，这个时间戳称为 zxid（Zookeeper Transaction Id）。而读请求只会相对于更新有序，也就是读请求的返回结果中会带有这个zookeeper 最新的 zxid。
配置java环境
详见文章 centos7配置jdk环境
下载地址：https://www.apache.org/dyn/closer.lua/zookeeper/zookeeper-3.8.0/apache-zookeeper-3.8.0-bin.tar.gz
wget https://www.apache.org/dyn/closer.lua/zookeeper/zookeeper-3.8.0/apache-zookeeper-3.8.0-bin.tar.gz
安装zookeeper
使用命令解压
tar -zxvf apache-zookeeper-3.8.0-bin.tar.gz
cd apache-zookeeper-3.8.0-bin
cd conf
cp zoo_sample.cfg zoo.cfg
修改配置文件
# 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=/www/server/apache-zookeeper-3.8.0-bin/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. # # https://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 ## Metrics Providers # # https://prometheus.io Metrics Exporter #metricsProvider.className=org.apache.zookeeper.metrics.prometheus.PrometheusMetricsProvider #metricsProvider.httpHost=0.0.0.0 #metricsProvider.httpPort=7000 #metricsProvider.exportJvmInfo=true
#zookeeper集群配置
server.1=192.168.31.20:3188:3288 server.2=192.168.31.21:3188:3288 server.3=192.168.31.22:3188:3288
启动zookeeper
进入文件夹的bin目录
cd bin/ ./zkServer.sh start ./zkServer.sh status ps -ef|grep zookeeper #配置zk环境变量 vim /etc/profile ZOOKEEPER_HOME=/www/server/apache-zookeeper-3.8.0-bin PATH=$PATH:$ZOOKEEPER_HOME/bin export PATH ZOOKEEPER_HOME PATH source /etc/profile
设置开机自动启动
#开机自启 vi /usr/lib/systemd/system/zookeeper.service [Unit] Description=zookeeper After=network.target remote-fs.target nss-lookup.target [Service] Type=forking ExecStart=/root/apache-zookeeper-3.7.0-bin/bin/zkServer.sh start ExecReload=/root/apache-zookeeper-3.7.0-bin/bin/zkServer.sh restart ExecStop=/root/apache-zookeeper-3.7.0-bin/bin/zkServer.sh stop [Install] WantedBy=multi-user.target
# 设置自启 systemctl enable zookeeper.service systemctl daemon-reload # 查看是否自启 systemctl is-enabled zookeeper.service # 取消自启 systemctl disable zookeeper.service systemctl daemon-reload
cd /www/server/apache-zookeeper-3.8.0-bin/bin
vi zkEnv.sh
#添加如下设置
JAVA_HOME="/www/server/jdk-19.0.1"
至此 zookeeper以及集群搭建完成
