zookeeper

1. 检查是否安装JDK

   rpm -qa|grep -E '^open[jre|jdk]|j[re|dk]'

2. 卸载已安装JDK

   rpm -qa|grep Java|xargs rpm -e --nodeps

3. yum安装jdk

   yum search java|grep jdk
   yum install java-1.8.0-openjdk

4. 检查安装是否成功

   java -version
   
   java version "1.8.0_101"
   Java(TM) SE Runtime Environment (build 1.8.0_101-b13)
   Java HotSpot(TM) 64-Bit Server VM (build 25.101-b13, mixed mode)

5. 下载并安装

   cd /root
   wget https://mirrors.tuna.tsinghua.edu.cn/apache/zookeeper/zookeeper-3.4.11/zookeeper-3.4.11.tar.gz
   tar -xvf zookeeper-3.4.11.tar.gz
   mv ./zookeeper-3.4.11 /usr/local/zookeeper
   mkdir /usr/local/zookeeper/var
   mkdir /usr/local/zookeeper/var/log
   echo 1 > /usr/local/zookeeper/var/log/myid
   cp /usr/local/zookeeper/conf/zoo_sample.cfg /usr/local/zookeeper/conf/zoo.cfg

6. 修改配置

   vim /usr/local/zookeeper/conf/zoo.cfg
   
   tickTime=2000
   initLimit=5
   syncLimit=2
   dataDir=/usr/local/zookeeper/var/log
   dataLogDir=/usr/local/zookeeper/var/log
   clientPort=2181
   # 多台server在下面配置即可,如果单台服务器构建多个server,则每个server用过的端口不能重复使用
   # 格式: server.[n]=[server_ip]:[server与leader交互端口]:[server选举leader端口]
   # server.1=172.31.9.59:2182:2183
   # server.2=172.31.9.60:2182:2183
   # server.3=172.31.9.61:2182:2183
   maxClientCnxns=60
   minSessionTimeout=60
   maxSessionTimeout=120
   # purgeInterval含义: 0-禁用自动清除 1-使用自动清除
   autopurge.purgeInterval=1
   
   ESC
   :wq

7. 安装zookeeper-c

   cd /usr/local/zookeeper/src/c
   
   ./configure
   
   make
   make install

8. 防火墙开启

   systemctl enable firewalld
   systemctl start firewalld
   firewall-cmd --zone=public --permanent --add-port=2181/tcp
   firewall-cmd --zone=public --permanent --add-port=2182/tcp
   firewall-cmd --zone=public --permanent --add-port=2183/tcp
   firewall-cmd --reload

9. 单元文件

   # 进入单元文件目录
   cd /etc/systemd/system
   
   # 创建redis单元文件,格式为: [单元文件名].[单元文件类型]
   vim zookeeper.service
   
   [Unit]
   Description=开机启动zookeeper.
   After=default.target network.target
   
   [Service]
   User=root
   Group=root
   Type=forking
   PIDFile=/usr/local/zookeeper/var/log/zookeeper_server.pid
   ExecStart=/usr/local/zookeeper/bin/zkServer.sh start
   ExecReload=/usr/local/zookeeper/bin/zkServer.sh restart
   ExecStop=/usr/local/zookeeper/bin/zkServer.sh stop
   PrivateTmp=false
   Restart=always
   
   [Install]
   WantedBy=multi-user.target
   
   ESC
   :wq

10. 安装php扩展:zookeeper参考链接

    cd /root
    wget https://pecl.php.net/get/zookeeper-0.4.0.tgz
    tar -zxvf zookeeper-0.4.0.tgz
    cd zookeeper-0.4.0/
    
    phpize
    ./configure
    make
    make install

11. 安装php扩展libzookeeper参考链接

    cd /root
    wget https://github.com/Timandes/libzookeeper/archive/v0.7.2.tar.gz
    tar -xvf v0.7.2.tar.gz
    cd libzookeeper-0.7.2
    
    phpize
    ./configure
    make
    make install
    
    # 用来调起zookeeper-admin,仓库地址:
    https://github.com/Timandes/zookeeper-admin.git

12. 修改php.ini

    vim /usr/local/php/lib/php.ini
    
    extension=libzookeeper.so
    extension=zookeeper.so
    
    ESC
    :wq

13. PHP使用进程公共锁

    # 出了$zc的作用域之后,锁将不存在
    $zc = new \Zookeeper('127.0.0.1:2181');
    //或者
    //$zc = new \Zookeeper();
    //$zc->connect('127.0.0.1:2181');
    $zookeeper_key = '/xxx';
    if ($zc->exists($zookeeper_key)) {
        //如果锁存在,则程序正在运行,不运行新的程序
        return false;
    }else{
        //如果锁文件不存在,则创建进程锁文件,运行程序
        $acl = [
            [
                'perms' => \Zookeeper::PERM_ALL,//共享锁(用来跨进程执行某个程序)
                'scheme' => 'world',
                'id' => 'anyone',
            ]
        ];
        //尝试创建锁
        $zookeeper_key_res = $zc->create($zookeeper_key, null, $acl, \Zookeeper::EPHEMERAL);//临时锁(可共享的)
        if ($zookeeper_key_res == $zookeeper_key) {
            //创建锁成功运行程序
            //做些什么,比如等待10秒
            sleep(10);
            $zc->delete($zookeeper_key);//其实不执行也会删除,因为这是一个临时锁,且return之后不再能取到$zc
            return true;
        } else {
            //创建锁失败不运行程序
            return false;
        }
    }