1、安装成功zookeeper后，在zookeeper 的bin目录下有启动相应的启动脚本
启动server
                      ./zkserver.sh start
启动client：(*注：cli需要安装java）
                     zkcli.sh
2、php实例：
get(  '/test' ,  array  ($this,  'watcher'  ) );
  }
}
$zoo =  new  zookeeperdemo(   '127.0.0.1:2181'  );
$zoo->get(  '/test' ,  array  ($zoo,  'watcher'  ) );
while  (  true  ) {
   echo  '.'   ;
  sleep(2);
}
leader与worker任务的分配：
class  worker  extends  zookeeper {
const  container =  '/cluster'  ;
protected  $acl   =  array (
                     array  (
                       'perms'  => zookeeper::  perm_all ,
                       'scheme'  =>  'world'   ,
                       'id'  =>  'anyone'  ) );
private  $isleader   =  false ;
private  $znode   ;
public function  __construct( $host =  '' , $watcher_cb =  null  , $recv_timeout = 10000 ) {
     parent :: __construct( $host, $watcher_cb, $recv_timeout );
  }
public function  register() {
     if ( ! $this->exists(  self  :: container   ) ) {
      $this->create(  self  :: container   ,  null , $this->  acl  );
    }
$this->znode = $this->create(  self  ::container .  '/w-'   ,
                                   null  ,
                                  $this->acl,
                                  zookeeper:: ephemeral | zookeeper::sequence );
$this->  znode  = str_replace(  self  :: container   . '/'   ,  ''   , $this->  znode  );
printf(  i'm registred as: %s\n , $this->   znode  );
$watching = $this->watchprevious();
if ( $watching == $this->   znode  ) {
      printf(  nobody here, i'm the leader\n  );
      $this->setleader(  true  );
    }
     else  {
      printf(  i'm watching %s\n  , $watching );
    }
  }
public function  watchprevious() {
    $workers = $this->getchildren(  self  :: container   );
    sort( $workers );
    $size = sizeof( $workers );
     for ( $i = 0 ; $i
       if ( $this->   znode  == $workers[ $i ] ) {
         if  ( $i > 0 ) {
          $this->get(  self  :: container   .  '/'  . $workers[ $i - 1 ],  array  ( $this,  'watchnode'  ) );
           return  $workers[ $i - 1 ];
        }
return  $workers[ $i ];
      }
    }
throw new  exception(  sprintf(  something went very wrong! i can't find myself: %s/%s ,
                           self  :: container   ,
                          $this->   znode  ) );
  }
public function  watchnode( $i, $type, $name ) {
    $watching = $this->watchprevious();
     if ( $watching == $this->   znode  ) {
      printf(  i'm the new leader!\n  );
      $this->setleader(  true  );
    }
     else  {
      printf(  now i'm watching %s\n  , $watching );
    }
  }
public function  isleader() {
     return  $this->   isleader  ;
  }
public function  setleader($flag) {
    $this->  isleader  = $flag;
  }
public function  run() {
    $this->register();
while (  true  ) {
       if ( $this->isleader() ) {
        $this->doleaderjob();
    }
     else  {
      $this->doworkerjob();
    }
sleep( 2 );
    }
  }
public function  doleaderjob() {
     echo  leading\n   ;
  }
public function  doworkerjob() {
     echo  working\n   ;
  }
}
$worker =  new  worker(  '127.0.0.1:2181'  );
$worker->run();
可以启动3个php进程，查看脚本的运行。
进程1：
[root@localhost zookeeper]# php -f worker.php
i'm registred as: w-0000000010
nobody here, i'm the leader
leading
进程2：
[daniel.luo@localhost zookeeper]$ php -f worker.php
i'm registred as: w-0000000011
i'm watching w-0000000010
working
进程3：
[daniel.luo@localhost zookeeper]$ php -f worker.php
i'm registred as: w-0000000012
i'm watching w-0000000011
working
ctrl + c 关闭leader进程后，会发现进程2与3会选举出新的leader