什么是ZooKeeper？
ZooKeeper是用於維護配置信息，命名，提供分布式同步以及提供組服務的集中式服務。所有這些類型的服務都以某種形式被分布式應用程序使用。每次實施它們時，都會進行很多工作來修復不可避免的錯誤和競爭條件。由於難以實現這類服務，因此應用程序最初通常會跳過它們，這會使它們在存在更改的情況下變得脆弱並且難以管理。即使部署正確，這些服務的不同實現也會導致管理復雜。
Zookeeper環境版本
| CentOS | JDK | zookeeper |
| 7.8 | 1.8.202 | 3.6.2 |
下載JDK1.8並且安裝
[root@Mike-Node1 ~]# wget https://repo.huaweicloud.com/java/jdk/8u202-b08/jdk-8u202-linux-x64.tar.gz [root@Mike-Node1 ~]# tar zxvf jdk-8u202-linux-x64.tar.gz -C /usr/local/ && rm -rf jdk-8u202-linux-x64.tar.gz [root@Mike-Node1 ~]# mv /usr/local/jdk1.8.0_202/ /usr/local/jdk/ [root@Mike-Node1 ~]# vim /etc/profile #set java environment JAVA_HOME=/usr/local/jdk CLASSPATH=.:$JAVA_HOME/lib.tools.jar PATH=$JAVA_HOME/bin:$PATH export JAVA_HOME CLASSPATH PATH [root@Mike-Node1 ~]# source /etc/profile [root@Mike-Node1 ~]# [root@Mike-Node1 ~]# java -version java version "1.8.0_202" Java(TM) SE Runtime Environment (build 1.8.0_202-b08) Java HotSpot(TM) 64-Bit Server VM (build 25.202-b08, mixed mode) [root@Mike-Node1 ~]#
下載zookeeper安裝
[root@Mike-Node1 ~]# wget https://mirror.bit.edu.cn/apache/zookeeper/zookeeper-3.6.2/apache-zookeeper-3.6.2-bin.tar.gz [root@Mike-Node1 ~]# tar zxvf apache-zookeeper-3.6.2-bin.tar.gz -C /usr/local/ [root@Mike-Node1 ~]# rm -rf apache-zookeeper-3.6.2-bin.tar.gz && mv /usr/local/apache-zookeeper-3.6.2-bin/ /usr/local/zookeeper [root@Mike-Node1 ~]# cd /usr/local/zookeeper/ [root@Mike-Node1 /usr/local/zookeeper]# cp conf/zoo_sample.cfg conf/zoo.cfg [root@Mike-Node1 /usr/local/zookeeper]# mkdir logs data [root@Mike-Node1 /usr/local/zookeeper]# cd conf/ [root@Mike-Node1 /usr/local/zookeeper/conf]# vim zoo.cfg tickTime=2000 initLimit=10 syncLimit=5 dataDir=/usr/local/zookeeper/data dataLogDir=/usr/local/zookeeper/logs clientPort=2181 [root@Mike-Node1 /usr/local/zookeeper/conf]#
啟動Zookeeper
[root@Mike-Node1 /usr/local/zookeeper/conf]# vim /etc/systemd/system/zookeeper.service [Unit] Description=zookeeper.service After=network.target [Service] Type=forking Environment=ZOO_LOG_DIR=/usr/local/zookeeper/logs/ Environment=PATH=/usr/local/jdk/bin:/usr/local/jdk/jre/bin:/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/root/bin:/root/bin ExecStart=/usr/local/zookeeper/bin/zkServer.sh start ExecStop=/usr/local/zookeeper/bin/zkServer.sh stop ExecReload=/usr/local/zookeeper/bin/zkServer.sh restart PIDFile=/usr/local/zookeeper/data/zookeeper_server.pid User=root [Install] WantedBy=multi-user.target [root@Mike-Node1 /usr/local/zookeeper/conf]# [root@Mike-Node1 /usr/local/zookeeper/conf]# systemctl daemon-reload [root@Mike-Node1 /usr/local/zookeeper/conf]# systemctl start zookeeper [root@Mike-Node1 /usr/local/zookeeper/conf]# systemctl enable zookeeper Created symlink from /etc/systemd/system/multi-user.target.wants/zookeeper.service to /etc/systemd/system/zookeeper.service. [root@Mike-Node1 /usr/local/zookeeper/conf]# [root@Mike-Node1 /usr/local/zookeeper/conf]# ss -ntl State Recv-Q Send-Q Local Address:Port Peer Address:Port LISTEN 0 128 *:22 *:* LISTEN 0 100 127.0.0.1:25 *:* LISTEN 0 50 [::]:38819 [::]:* LISTEN 0 50 [::]:2181 [::]:* LISTEN 0 50 [::]:8080 [::]:* LISTEN 0 100 [::1]:25 [::]:* [root@Mike-Node1 /usr/local/zookeeper/conf]#
你會突然發現多了端口，舊版本只有一個2181端口，現在突然多出 8080端口和38819端口
默認訪問8080端口地址：
http://127.0.0.1:8080/commands
這是因為 zookeeper3.5 版本以上的新特性：
he AdminServer New in 3.5.0: The AdminServer is an embedded Jetty server that provides an HTTP interface to the four letter word commands. By default, the server is started on port 8080, and commands are issued by going to the URL "/commands/[command name]", e.g., http://localhost:8080/commands/stat. The command response is returned as JSON. Unlike the original protocol, commands are not restricted to four-letter names, and commands can have multiple names; for instance, "stmk" can also be referred to as "set_trace_mask". To view a list of all available commands, point a browser to the URL /commands (e.g., http://localhost:8080/commands). See the AdminServer configuration options for how to change the port and URLs. 這是Zookeeper AdminServer，默認使用8080端口，它的配置屬性如下： New in 3.5.0: The following options are used to configure the AdminServer. admin.enableServer : (Java system property: zookeeper.admin.enableServer) Set to "false" to disable the AdminServer. By default the AdminServer is enabled. admin.serverAddress : (Java system property: zookeeper.admin.serverAddress) The address the embedded Jetty server listens on. Defaults to 0.0.0.0. admin.serverPort : (Java system property: zookeeper.admin.serverPort) The port the embedded Jetty server listens on. Defaults to 8080. admin.idleTimeout : (Java system property: zookeeper.admin.idleTimeout) Set the maximum idle time in milliseconds that a connection can wait before sending or receiving data. Defaults to 30000 ms. admin.commandURL : (Java system property: zookeeper.admin.commandURL) The URL for listing and issuing commands relative to the root URL. Defaults to "/commands".
如果服務器上有8080端口可能還會報錯，啟動不了~
那么需要在配置文件中修改 AdminServer 默認8080端口，如下
[root@Mike-Node1 ~]# vim /usr/local/zookeeper/conf/zoo.cfg admin.serverPort=8989 [root@Mike-Node1 ~]# systemctl restart zookeeper [root@Mike-Node1 ~]# ss -ntl State Recv-Q Send-Q Local Address:Port Peer Address:Port LISTEN 0 128 *:22 *:* LISTEN 0 100 127.0.0.1:25 *:* LISTEN 0 50 [::]:2181 [::]:* LISTEN 0 50 [::]:36046 [::]:* LISTEN 0 100 [::1]:25 [::]:* LISTEN 0 50 [::]:8989 [::]:* [root@Mike-Node1 ~]#
開放防火牆
[root@Mike-node1 ~]# firewall-cmd --zone=public --add-port=2181/tcp --permanent [root@Mike-node1 ~]# firewall-cmd --zone=public --add-port=8989/tcp --permanent [root@Mike-node1 ~]# firewall-cmd –reload
或者關閉防火牆
[root@Mike-node1 ~]# systemctl stop firewalld
[root@Mike-node1 ~]# systemctl stop iptables
如果對防火牆有疑惑可以看我之前的博客 https://www.cnblogs.com/mike666/p/13932326.html
服務操作命令
systemctl start zookeeper #啟動服務
systemctl stop zookeeper #停止服務
systemctl restart zookeeper #重新啟動服務
systemctl status zookeeper #查看服務當前狀態
systemctl enable zookeeper #設置開機自啟動
systemctl disable zookeeper #停止開機自啟動
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