ZooKeeper安装运行

ZooKeeper介绍

ZooKeeper是Hadoop的正式子项目，它是一个针对大型分布式系统的可靠协调系统，提供的功能包括：配置维护、名字服务、分布式同步、组服务等。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是Google的Chubby一个开源的实现.是高有效和可靠的协同工作系统.Zookeeper能够用来leader选举,配置信息维护等.在一个分布式的环境中,我们需要一个Master实例或存储一些配置信息,确保文件写入的一致性等.Zookeeper能够保证如下3点:

• Watches are ordered with respect to other events, other watches, and
  asynchronous replies. The ZooKeeper client libraries ensures that
  everything is dispatched in order.
• A client will see a watch event for a znode it is watching before seeing the new data that corresponds to that znode.
• The order of watch events from ZooKeeper corresponds to the order of the updates as seen by the ZooKeeper service.

在Zookeeper中,znode是一个跟Unix文件系统路径相似的节点,可以往这个节点存储或获取数据.如果在创建znode时Flag设置 为EPHEMERAL,那么当这个创建这个znode的节点和Zookeeper失去连接后,这个znode将不再存在在Zookeeper 里.Zookeeper使用Watcher察觉事件信息,当客户端接收到事件信息,比如连接超时,节点数据改变,子节点改变,可以调用相应的行为来处理数 据.Zookeeper的Wiki页面展示了如何使用Zookeeper来处理事件通知,队列,优先队列,锁,共享锁,可撤销的共享锁,两阶段提交.

ZooKeeper官网

Zookeeper官网

ZooKeeper安装

首先下载最新版zookeeper-3.4.5.tar.gz

然后解压

tar zxvf zookeeper-3.4.5.tar.gz

然后进入conf目录修改zoo_sample.cfg为zoo.cfg

然后vi zoo.cfg

更改为：

# 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=/tmp/zookeeper
# the port at which the clients will connect
clientPort=2181
#
# Be sure to read the maintenance section of the 
# administrator guide before turning on autopurge.
#
# http://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

编辑保存后进入bin目录执行

./zkServer.sh start

ZooKeeper测试

[root@localhost bin]# ./zkCli.sh
Connecting to localhost:2181
2013-01-16 14:36:22,484 [myid:] - INFO  [main:Environment@100] - Client environment:zookeeper.version=3.4.5-1392090, built on 09/30/2012 17:52 GMT
2013-01-16 14:36:22,488 [myid:] - INFO  [main:Environment@100] - Client environment:host.name=localhost.localdomain
2013-01-16 14:36:22,489 [myid:] - INFO  [main:Environment@100] - Client environment:java.version=1.6.0_29
2013-01-16 14:36:22,489 [myid:] - INFO  [main:Environment@100] - Client environment:java.vendor=Sun Microsystems Inc.
2013-01-16 14:36:22,490 [myid:] - INFO  [main:Environment@100] - Client environment:java.home=/usr/java/jdk1.6.0_29/jre
2013-01-16 14:36:22,490 [myid:] - INFO  [main:Environment@100] - Client environment:java.class.path=/usr/local/zookeeper-3.4.5/bin/../build/classes:/usr/local/zookeeper-3.4.5/bin/../build/lib/*.jar:/usr/local/zookeeper-3.4.5/bin/../lib/slf4j-log4j12-1.6.1.jar:/usr/local/zookeeper-3.4.5/bin/../lib/slf4j-api-1.6.1.jar:/usr/local/zookeeper-3.4.5/bin/../lib/netty-3.2.2.Final.jar:/usr/local/zookeeper-3.4.5/bin/../lib/log4j-1.2.15.jar:/usr/local/zookeeper-3.4.5/bin/../lib/jline-0.9.94.jar:/usr/local/zookeeper-3.4.5/bin/../zookeeper-3.4.5.jar:/usr/local/zookeeper-3.4.5/bin/../src/java/lib/*.jar:/usr/local/zookeeper-3.4.5/bin/../conf:./:/usr/java/jdk1.6.0_29/lib:/usr/java/jdk1.6.0_29/jre/lib
2013-01-16 14:36:22,491 [myid:] - INFO  [main:Environment@100] - Client environment:java.library.path=/usr/java/jdk1.6.0_29/jre/lib/i386/client:/usr/java/jdk1.6.0_29/jre/lib/i386:/usr/java/jdk1.6.0_29/jre/../lib/i386:/usr/java/packages/lib/i386:/lib:/usr/lib
2013-01-16 14:36:22,491 [myid:] - INFO  [main:Environment@100] - Client environment:java.io.tmpdir=/tmp
2013-01-16 14:36:22,491 [myid:] - INFO  [main:Environment@100] - Client environment:java.compiler=<NA>
2013-01-16 14:36:22,492 [myid:] - INFO  [main:Environment@100] - Client environment:os.name=Linux
2013-01-16 14:36:22,492 [myid:] - INFO  [main:Environment@100] - Client environment:os.arch=i386
2013-01-16 14:36:22,493 [myid:] - INFO  [main:Environment@100] - Client environment:os.version=2.6.18-308.24.1.el5
2013-01-16 14:36:22,493 [myid:] - INFO  [main:Environment@100] - Client environment:user.name=root
2013-01-16 14:36:22,493 [myid:] - INFO  [main:Environment@100] - Client environment:user.home=/root
2013-01-16 14:36:22,494 [myid:] - INFO  [main:Environment@100] - Client environment:user.dir=/usr/local/zookeeper-3.4.5/bin
2013-01-16 14:36:22,496 [myid:] - INFO  [main:ZooKeeper@438] - Initiating client connection, connectString=localhost:2181 sessionTimeout=30000 watcher=org.apache.zookeeper.ZooKeeperMain$MyWatcher@5ffb18
Welcome to ZooKeeper!
2013-01-16 14:36:22,592 [myid:] - INFO  [main-SendThread(localhost.localdomain:2181):ClientCnxn$SendThread@966] - Opening socket connection to server localhost.localdomain/127.0.0.1:2181. Will not attempt to authenticate using SASL (无法定位登录配置)
2013-01-16 14:36:22,601 [myid:] - INFO  [main-SendThread(localhost.localdomain:2181):ClientCnxn$SendThread@849] - Socket connection established to localhost.localdomain/127.0.0.1:2181, initiating session
JLine support is enabled
2013-01-16 14:36:22,693 [myid:] - INFO  [main-SendThread(localhost.localdomain:2181):ClientCnxn$SendThread@1207] - Session establishment complete on server localhost.localdomain/127.0.0.1:2181, sessionid = 0x13c3c5224cc0000, negotiated timeout = 30000

WATCHER::

WatchedEvent state:SyncConnected type:None path:null
[zk: localhost:2181(CONNECTED) 0] help
ZooKeeper -server host:port cmd args
        connect host:port
        get path [watch]
        ls path [watch]
        set path data [version]
        rmr path
        delquota [-n|-b] path
        quit 
        printwatches on|off
        create [-s] [-e] path data acl
        stat path [watch]
        close 
        ls2 path [watch]
        history 
        listquota path
        setAcl path acl
        getAcl path
        sync path
        redo cmdno
        addauth scheme auth
        delete path [version]
        setquota -n|-b val path
[zk: localhost:2181(CONNECTED) 1] create /my_data "data.ch.com"
Created /my_data
[zk: localhost:2181(CONNECTED) 2] get /my_data
"data.ch.com"
cZxid = 0x2
ctime = Wed Jan 16 14:38:20 CST 2013
mZxid = 0x2
mtime = Wed Jan 16 14:38:20 CST 2013
pZxid = 0x2
cversion = 0
dataVersion = 0
aclVersion = 0
ephemeralOwner = 0x0
dataLength = 13
numChildren = 0
[zk: localhost:2181(CONNECTED) 3] set /my_date "123456.com"
Node does not exist: /my_date
[zk: localhost:2181(CONNECTED) 4] set /my_data "123456.com"
cZxid = 0x2
ctime = Wed Jan 16 14:38:20 CST 2013
mZxid = 0x4
mtime = Wed Jan 16 14:38:58 CST 2013
pZxid = 0x2
cversion = 0
dataVersion = 1
aclVersion = 0
ephemeralOwner = 0x0
dataLength = 12
numChildren = 0
[zk: localhost:2181(CONNECTED) 5] get /my_data
"123456.com"
cZxid = 0x2
ctime = Wed Jan 16 14:38:20 CST 2013
mZxid = 0x4
mtime = Wed Jan 16 14:38:58 CST 2013
pZxid = 0x2
cversion = 0
dataVersion = 1
aclVersion = 0
ephemeralOwner = 0x0
dataLength = 12
numChildren = 0
[zk: localhost:2181(CONNECTED) 6] create /mytemp "你好吗"
Created /mytemp
[zk: localhost:2181(CONNECTED) 7] get /myt
Node does not exist: /myt
[zk: localhost:2181(CONNECTED) 8] get /mytemp
"你好吗"
cZxid = 0x5
ctime = Wed Jan 16 14:40:44 CST 2013
mZxid = 0x5
mtime = Wed Jan 16 14:40:44 CST 2013
pZxid = 0x5
cversion = 0
dataVersion = 0
aclVersion = 0
ephemeralOwner = 0x0
dataLength = 11
numChildren = 0
[zk: localhost:2181(CONNECTED) 9] get /mytemp
"你好吗"
cZxid = 0x5
ctime = Wed Jan 16 14:40:44 CST 2013
mZxid = 0x5
mtime = Wed Jan 16 14:40:44 CST 2013
pZxid = 0x5
cversion = 0
dataVersion = 0
aclVersion = 0
ephemeralOwner = 0x0
dataLength = 11
numChildren = 0
[zk: localhost:2181(CONNECTED) 10] get /my_data
"123456.com"
cZxid = 0x2
ctime = Wed Jan 16 14:38:20 CST 2013
mZxid = 0x4
mtime = Wed Jan 16 14:38:58 CST 2013
pZxid = 0x2
cversion = 0
dataVersion = 1
aclVersion = 0
ephemeralOwner = 0x0
dataLength = 12
numChildren = 0
[zk: localhost:2181(CONNECTED) 11] ls
ZooKeeper -server host:port cmd args
        connect host:port
        get path [watch]
        ls path [watch]
        set path data [version]
        rmr path
        delquota [-n|-b] path
        quit 
        printwatches on|off
        create [-s] [-e] path data acl
        stat path [watch]
        close 
        ls2 path [watch]
        history 
        listquota path
        setAcl path acl
        getAcl path
        sync path
        redo cmdno
        addauth scheme auth
        delete path [version]
        setquota -n|-b val path
[zk: localhost:2181(CONNECTED) 12]