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）
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zkCli.sh
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2、PHP实例：
class ZookeeperDemo extends Zookeeper {
public function watcher( $i, $type, $key ) {
echo "Insider Watcher\n" ;
// Watcher gets consumed so we need to set a new one
$this->get( '/test' , array ($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
