ZooKeeper是一个分布式开源框架,提供了协调分布式应用的基本服务,它向外部应用暴露一组通用服务——分布式同步(Distributed Synchronization)、命名服务(Naming Service)、集群维护(Group Maintenance)等,简化分布式应用协调及其管理的难度,提供高性能的分布式服务。ZooKeeper自己能够以Standalone模式安装运行,不过它的长处在于经过分布式ZooKeeper集群(一个Leader,多个Follower),基于必定的策略来保证ZooKeeper集群的稳定性和可用性,从而实现分布式应用的可靠性。html
有关ZooKeeper的介绍,网上不少,也能够参考文章后面,我整理的一些相关连接。java
下面,咱们简单说明一下ZooKeeper的配置。算法
从Apache网站上(zookeeper.apache.org)下载ZooKeeper软件包,我选择了3.3.4版本的(zookeeper-3.3.4.tar.gz),在一台Linux机器上安装很是容易,只须要解压缩后,简单配置一下便可以启动ZooKeeper服务器进程。apache
将zookeeper-3.3.4/conf目录下面的 zoo_sample.cfg修改成zoo.cfg,配置文件内容以下所示:服务器
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tickTime=2000 架构
dataDir=/home/hadoop/storage/zookeeper 框架
clientPort=2181 less
initLimit=5 socket
syncLimit=2
上面各个配置参数的含义也很是简单,引用以下所示:
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tickTime —— the basic time unit in milliseconds used by ZooKeeper. It is used to do heartbeats and the minimum session timeout will be twice the tickTime.
dataDir —— the location to store the in-memory database snapshots and, unless specified otherwise, the transaction log of updates to the database.
clientPort —— the port to listen for client connections
下面启动ZooKeeper服务器进程:
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cd zookeeper-3.3.4/
bin/zkServer.sh start
经过jps命令能够查看ZooKeeper服务器进程,名称为QuorumPeerMain。
在客户端链接ZooKeeper服务器,执行以下命令:
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bin/zkCli.sh -server dynamic:2181
上面dynamic是个人主机名,若是在本机执行,则执行以下命令便可:
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bin/zkCli.sh
客户端链接信息以下所示:
接着,可使用help查看Zookeeper客户端可使用的基本操做命令。
ZooKeeper分布式模式安装(ZooKeeper集群)也比较容易,这里说明一下基本要点。
首先要明确的是,ZooKeeper集群是一个独立的分布式协调服务集群,“独立”的含义就是说,若是想使用ZooKeeper实现分布式应用的协调与管理,简化协调与管理,任何分布式应用均可以使用,这就要归功于Zookeeper的数据模型(Data Model)和层次命名空间(Hierarchical Namespace)结构,详细能够参考http://zookeeper.apache.org/doc/trunk/zookeeperOver.html。在设计你的分布式应用协调服务时,首要的就是考虑如何组织层次命名空间。
下面说明分布式模式的安装配置,过程以下所示:
第一步:主机名称到IP地址映射配置
ZooKeeper集群中具备两个关键的角色:Leader和Follower。集群中全部的结点做为一个总体对分布式应用提供服务,集群中每一个结点之间都互相链接,因此,在配置的ZooKeeper集群的时候,每个结点的host到IP地址的映射都要配置上集群中其它结点的映射信息。
例如,个人ZooKeeper集群中每一个结点的配置,以slave-01为例,/etc/hosts内容以下所示:
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192.168.0.179 slave-01
192.168.0.178 slave-02
192.168.0.177 slave-03
ZooKeeper采用一种称为Leader election的选举算法。在整个集群运行过程当中,只有一个Leader,其余的都是Follower,若是ZooKeeper集群在运行过程当中Leader出了问题,系统会采用该算法从新选出一个Leader。所以,各个结点之间要可以保证互相链接,必须配置上述映射。
ZooKeeper集群启动的时候,会首先选出一个Leader,在Leader election过程当中,某一个知足选举算的结点就能成为Leader。整个集群的架构能够参考http://zookeeper.apache.org/doc/trunk/zookeeperOver.html#sc_designGoals。
第二步:修改ZooKeeper配置文件
在其中一台机器(slave-01)上,解压缩zookeeper-3.3.4.tar.gz,修改配置文件conf/zoo.cfg,内容以下所示:
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tickTime=2000
dataDir=/home/hadoop/storage/zookeeper
clientPort=2181
initLimit=5
syncLimit=2
server.1=slave-01:2888:3888
server.2=slave-02:2888:3888
server.3=slave-03:2888:3888
上述配置内容说明,能够参考http://zookeeper.apache.org/doc/trunk/zookeeperStarted.html#sc_RunningReplicatedZooKeeper。
server.A=B:C:D
server.1=edu-zk-01:2881:3881
server.2=edu-zk-02:2882:3882
server.3=edu-zk-03:2883:3883
A是一个数字,表示这个是第几号服务器;
B是这个服务器的IP地址(或者是与IP地址作了映射的主机名);
C第一个端口用来集群成员的信息交换,表示这个服务器与集群中的Leader服务器交换信息的端口;
D是在leader挂掉时专门用来进行选举leader所用的端口。
注意:若是是伪集群的配置方式,不一样的 Zookeeper 实例通讯端口号不能同样,因此要给它们分配不一样的端口号。
第三步:远程复制分发安装文件
上面已经在一台机器slave-01上配置完成ZooKeeper,如今能够将该配置好的安装文件远程拷贝到集群中的各个结点对应的目录下:
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cd /home/hadoop/installation/
scp -r zookeeper-3.3.4/ hadoop@slave-02:/home/hadoop/installation/
scp -r zookeeper-3.3.4/ hadoop@slave-03:/home/hadoop/installation/
第四步:设置myid
在咱们配置的dataDir指定的目录下面,建立一个myid文件,里面内容为一个数字,用来标识当前主机,conf/zoo.cfg文件中配置的server.X中X为何数字,则myid文件中就输入这个数字,例如:
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hadoop@slave-01:~/installation/zookeeper-3.3.4$ echo "1" > /home/hadoop/storage/zookeeper/myid
hadoop@slave-02:~/installation/zookeeper-3.3.4$ echo "2" > /home/hadoop/storage/zookeeper/myid
hadoop@slave-03:~/installation/zookeeper-3.3.4$ echo "3" > /home/hadoop/storage/zookeeper/myid
按照上述进行配置便可。
第五步:启动ZooKeeper集群
在ZooKeeper集群的每一个结点上,执行启动ZooKeeper服务的脚本,以下所示:
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hadoop@slave-01:~/installation/zookeeper-3.3.4$ bin/zkServer.sh start
hadoop@slave-02:~/installation/zookeeper-3.3.4$ bin/zkServer.sh start
hadoop@slave-03:~/installation/zookeeper-3.3.4$ bin/zkServer.sh start
以结点slave-01为例,日志以下所示:
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hadoop@slave-01:~/installation/zookeeper-3.3.4$ tail -500f zookeeper.out
2012-01-08 06:51:19,117 - INFO [main:QuorumPeerConfig@90] - Reading configuration from: /home/hadoop/installation/zookeeper-3.3.4/bin/../conf/zoo.cfg
2012-01-08 06:51:19,133 - INFO [main:QuorumPeerConfig@310] - Defaulting to majority quorums
2012-01-08 06:51:19,167 - INFO [main:QuorumPeerMain@119] - Starting quorum peer
2012-01-08 06:51:19,227 - INFO [main:NIOServerCnxn$Factory@143] - binding to port 0.0.0.0/0.0.0.0:2181
2012-01-08 06:51:19,277 - INFO [main:QuorumPeer@819] - tickTime set to 2000
2012-01-08 06:51:19,278 - INFO [main:QuorumPeer@830] - minSessionTimeout set to -1
2012-01-08 06:51:19,279 - INFO [main:QuorumPeer@841] - maxSessionTimeout set to -1
2012-01-08 06:51:19,281 - INFO [main:QuorumPeer@856] - initLimit set to 5
2012-01-08 06:51:19,347 - INFO [Thread-1:QuorumCnxManager$Listener@473] - My election bind port: 3888
2012-01-08 06:51:19,393 - INFO [QuorumPeer:/0:0:0:0:0:0:0:0:2181:QuorumPeer@621] - LOOKING
2012-01-08 06:51:19,396 - INFO [QuorumPeer:/0:0:0:0:0:0:0:0:2181:FastLeaderElection@663] - New election. My id = 1, Proposed zxid = 0
2012-01-08 06:51:19,400 - INFO [WorkerReceiver Thread:FastLeaderElection@496] - Notification: 1 (n.leader), 0 (n.zxid), 1 (n.round), LOOKING (n.state), 1 (n.sid), LOOKING (my state)
2012-01-08 06:51:19,416 - WARN [WorkerSender Thread:QuorumCnxManager@384] - Cannot open channel to 2 at election address slave-02/192.168.0.178:3888
java.net.ConnectException: Connection refused
at sun.nio.ch.SocketChannelImpl.checkConnect(Native Method)
at sun.nio.ch.SocketChannelImpl.finishConnect(SocketChannelImpl.java:567)
at sun.nio.ch.SocketAdaptor.connect(SocketAdaptor.java:100)
at org.apache.zookeeper.server.quorum.QuorumCnxManager.connectOne(QuorumCnxManager.java:371)
at org.apache.zookeeper.server.quorum.QuorumCnxManager.toSend(QuorumCnxManager.java:340)
at org.apache.zookeeper.server.quorum.FastLeaderElection$Messenger$WorkerSender.process(FastLeaderElection.java:360)
at org.apache.zookeeper.server.quorum.FastLeaderElection$Messenger$WorkerSender.run(FastLeaderElection.java:333)
at java.lang.Thread.run(Thread.java:662)
2012-01-08 06:51:19,420 - WARN [WorkerSender Thread:QuorumCnxManager@384] - Cannot open channel to 3 at election address slave-03/192.168.0.177:3888
java.net.ConnectException: Connection refused
at sun.nio.ch.SocketChannelImpl.checkConnect(Native Method)
at sun.nio.ch.SocketChannelImpl.finishConnect(SocketChannelImpl.java:567)
at sun.nio.ch.SocketAdaptor.connect(SocketAdaptor.java:100)
at org.apache.zookeeper.server.quorum.QuorumCnxManager.connectOne(QuorumCnxManager.java:371)
at org.apache.zookeeper.server.quorum.QuorumCnxManager.toSend(QuorumCnxManager.java:340)
at org.apache.zookeeper.server.quorum.FastLeaderElection$Messenger$WorkerSender.process(FastLeaderElection.java:360)
at org.apache.zookeeper.server.quorum.FastLeaderElection$Messenger$WorkerSender.run(FastLeaderElection.java:333)
at java.lang.Thread.run(Thread.java:662)
2012-01-08 06:51:19,612 - WARN [QuorumPeer:/0:0:0:0:0:0:0:0:2181:QuorumCnxManager@384] - Cannot open channel to 2 at election address slave-02/192.168.0.178:3888
java.net.ConnectException: Connection refused
at sun.nio.ch.SocketChannelImpl.checkConnect(Native Method)
at sun.nio.ch.SocketChannelImpl.finishConnect(SocketChannelImpl.java:567)
at sun.nio.ch.SocketAdaptor.connect(SocketAdaptor.java:100)
at org.apache.zookeeper.server.quorum.QuorumCnxManager.connectOne(QuorumCnxManager.java:371)
at org.apache.zookeeper.server.quorum.QuorumCnxManager.connectAll(QuorumCnxManager.java:404)
at org.apache.zookeeper.server.quorum.FastLeaderElection.lookForLeader(FastLeaderElection.java:688)
at org.apache.zookeeper.server.quorum.QuorumPeer.run(QuorumPeer.java:622)
2012-01-08 06:51:19,615 - WARN [QuorumPeer:/0:0:0:0:0:0:0:0:2181:QuorumCnxManager@384] - Cannot open channel to 3 at election address slave-03/192.168.0.177:3888
java.net.ConnectException: Connection refused
at sun.nio.ch.SocketChannelImpl.checkConnect(Native Method)
at sun.nio.ch.SocketChannelImpl.finishConnect(SocketChannelImpl.java:567)
at sun.nio.ch.SocketAdaptor.connect(SocketAdaptor.java:100)
at org.apache.zookeeper.server.quorum.QuorumCnxManager.connectOne(QuorumCnxManager.java:371)
at org.apache.zookeeper.server.quorum.QuorumCnxManager.connectAll(QuorumCnxManager.java:404)
at org.apache.zookeeper.server.quorum.FastLeaderElection.lookForLeader(FastLeaderElection.java:688)
at org.apache.zookeeper.server.quorum.QuorumPeer.run(QuorumPeer.java:622)
2012-01-08 06:51:19,616 - INFO [QuorumPeer:/0:0:0:0:0:0:0:0:2181:FastLeaderElection@697] - Notification time out: 400
2012-01-08 06:51:20,019 - WARN [QuorumPeer:/0:0:0:0:0:0:0:0:2181:QuorumCnxManager@384] - Cannot open channel to 2 at election address slave-02/192.168.0.178:3888
java.net.ConnectException: Connection refused
at sun.nio.ch.SocketChannelImpl.checkConnect(Native Method)
at sun.nio.ch.SocketChannelImpl.finishConnect(SocketChannelImpl.java:567)
at sun.nio.ch.SocketAdaptor.connect(SocketAdaptor.java:100)
at org.apache.zookeeper.server.quorum.QuorumCnxManager.connectOne(QuorumCnxManager.java:371)
at org.apache.zookeeper.server.quorum.QuorumCnxManager.connectAll(QuorumCnxManager.java:404)
at org.apache.zookeeper.server.quorum.FastLeaderElection.lookForLeader(FastLeaderElection.java:688)
at org.apache.zookeeper.server.quorum.QuorumPeer.run(QuorumPeer.java:622)
2012-01-08 06:51:20,021 - WARN [QuorumPeer:/0:0:0:0:0:0:0:0:2181:QuorumCnxManager@384] - Cannot open channel to 3 at election address slave-03/192.168.0.177:3888
java.net.ConnectException: Connection refused
at sun.nio.ch.SocketChannelImpl.checkConnect(Native Method)
at sun.nio.ch.SocketChannelImpl.finishConnect(SocketChannelImpl.java:567)
at sun.nio.ch.SocketAdaptor.connect(SocketAdaptor.java:100)
at org.apache.zookeeper.server.quorum.QuorumCnxManager.connectOne(QuorumCnxManager.java:371)
at org.apache.zookeeper.server.quorum.QuorumCnxManager.connectAll(QuorumCnxManager.java:404)
at org.apache.zookeeper.server.quorum.FastLeaderElection.lookForLeader(FastLeaderElection.java:688)
at org.apache.zookeeper.server.quorum.QuorumPeer.run(QuorumPeer.java:622)
2012-01-08 06:51:20,022 - INFO [QuorumPeer:/0:0:0:0:0:0:0:0:2181:FastLeaderElection@697] - Notification time out: 800
2012-01-08 06:51:20,825 - WARN [QuorumPeer:/0:0:0:0:0:0:0:0:2181:QuorumCnxManager@384] - Cannot open channel to 2 at election address slave-02/192.168.0.178:3888
java.net.ConnectException: Connection refused
at sun.nio.ch.SocketChannelImpl.checkConnect(Native Method)
at sun.nio.ch.SocketChannelImpl.finishConnect(SocketChannelImpl.java:567)
at sun.nio.ch.SocketAdaptor.connect(SocketAdaptor.java:100)
at org.apache.zookeeper.server.quorum.QuorumCnxManager.connectOne(QuorumCnxManager.java:371)
at org.apache.zookeeper.server.quorum.QuorumCnxManager.connectAll(QuorumCnxManager.java:404)
at org.apache.zookeeper.server.quorum.FastLeaderElection.lookForLeader(FastLeaderElection.java:688)
at org.apache.zookeeper.server.quorum.QuorumPeer.run(QuorumPeer.java:622)
2012-01-08 06:51:20,827 - WARN [QuorumPeer:/0:0:0:0:0:0:0:0:2181:QuorumCnxManager@384] - Cannot open channel to 3 at election address slave-03/192.168.0.177:3888
java.net.ConnectException: Connection refused
at sun.nio.ch.SocketChannelImpl.checkConnect(Native Method)
at sun.nio.ch.SocketChannelImpl.finishConnect(SocketChannelImpl.java:567)
at sun.nio.ch.SocketAdaptor.connect(SocketAdaptor.java:100)
at org.apache.zookeeper.server.quorum.QuorumCnxManager.connectOne(QuorumCnxManager.java:371)
at org.apache.zookeeper.server.quorum.QuorumCnxManager.connectAll(QuorumCnxManager.java:404)
at org.apache.zookeeper.server.quorum.FastLeaderElection.lookForLeader(FastLeaderElection.java:688)
at org.apache.zookeeper.server.quorum.QuorumPeer.run(QuorumPeer.java:622)
2012-01-08 06:51:20,828 - INFO [QuorumPeer:/0:0:0:0:0:0:0:0:2181:FastLeaderElection@697] - Notification time out: 1600
2012-01-08 06:51:22,435 - WARN [QuorumPeer:/0:0:0:0:0:0:0:0:2181:QuorumCnxManager@384] - Cannot open channel to 2 at election address slave-02/192.168.0.178:3888
java.net.ConnectException: Connection refused
at sun.nio.ch.SocketChannelImpl.checkConnect(Native Method)
at sun.nio.ch.SocketChannelImpl.finishConnect(SocketChannelImpl.java:567)
at sun.nio.ch.SocketAdaptor.connect(SocketAdaptor.java:100)
at org.apache.zookeeper.server.quorum.QuorumCnxManager.connectOne(QuorumCnxManager.java:371)
at org.apache.zookeeper.server.quorum.QuorumCnxManager.connectAll(QuorumCnxManager.java:404)
at org.apache.zookeeper.server.quorum.FastLeaderElection.lookForLeader(FastLeaderElection.java:688)
at org.apache.zookeeper.server.quorum.QuorumPeer.run(QuorumPeer.java:622)
2012-01-08 06:51:22,439 - WARN [QuorumPeer:/0:0:0:0:0:0:0:0:2181:QuorumCnxManager@384] - Cannot open channel to 3 at election address slave-03/192.168.0.177:3888
java.net.ConnectException: Connection refused
at sun.nio.ch.SocketChannelImpl.checkConnect(Native Method)
at sun.nio.ch.SocketChannelImpl.finishConnect(SocketChannelImpl.java:567)
at sun.nio.ch.SocketAdaptor.connect(SocketAdaptor.java:100)
at org.apache.zookeeper.server.quorum.QuorumCnxManager.connectOne(QuorumCnxManager.java:371)
at org.apache.zookeeper.server.quorum.QuorumCnxManager.connectAll(QuorumCnxManager.java:404)
at org.apache.zookeeper.server.quorum.FastLeaderElection.lookForLeader(FastLeaderElection.java:688)
at org.apache.zookeeper.server.quorum.QuorumPeer.run(QuorumPeer.java:622)
2012-01-08 06:51:22,441 - INFO [QuorumPeer:/0:0:0:0:0:0:0:0:2181:FastLeaderElection@697] - Notification time out: 3200
2012-01-08 06:51:22,945 - INFO [WorkerReceiver Thread:FastLeaderElection@496] - Notification: 2 (n.leader), 0 (n.zxid), 1 (n.round), LOOKING (n.state), 2 (n.sid), LOOKING (my state)
2012-01-08 06:51:22,946 - INFO [QuorumPeer:/0:0:0:0:0:0:0:0:2181:FastLeaderElection@721] - Updating proposal
2012-01-08 06:51:22,949 - WARN [WorkerSender Thread:QuorumCnxManager@384] - Cannot open channel to 3 at election address slave-03/192.168.0.177:3888
java.net.ConnectException: Connection refused
at sun.nio.ch.SocketChannelImpl.checkConnect(Native Method)
at sun.nio.ch.SocketChannelImpl.finishConnect(SocketChannelImpl.java:567)
at sun.nio.ch.SocketAdaptor.connect(SocketAdaptor.java:100)
at org.apache.zookeeper.server.quorum.QuorumCnxManager.connectOne(QuorumCnxManager.java:371)
at org.apache.zookeeper.server.quorum.QuorumCnxManager.toSend(QuorumCnxManager.java:340)
at org.apache.zookeeper.server.quorum.FastLeaderElection$Messenger$WorkerSender.process(FastLeaderElection.java:360)
at org.apache.zookeeper.server.quorum.FastLeaderElection$Messenger$WorkerSender.run(FastLeaderElection.java:333)
at java.lang.Thread.run(Thread.java:662)
2012-01-08 06:51:22,951 - INFO [WorkerReceiver Thread:FastLeaderElection@496] - Notification: 2 (n.leader), 0 (n.zxid), 1 (n.round), LOOKING (n.state), 1 (n.sid), LOOKING (my state)
2012-01-08 06:51:23,156 - INFO [QuorumPeer:/0:0:0:0:0:0:0:0:2181:QuorumPeer@643] - FOLLOWING
2012-01-08 06:51:23,170 - INFO [QuorumPeer:/0:0:0:0:0:0:0:0:2181:Learner@80] - TCP NoDelay set to: true
2012-01-08 06:51:23,206 - INFO [QuorumPeer:/0:0:0:0:0:0:0:0:2181:Environment@97] - Server environment:zookeeper.version=3.3.3-1203054, built on 11/17/2011 05:47 GMT
2012-01-08 06:51:23,207 - INFO [QuorumPeer:/0:0:0:0:0:0:0:0:2181:Environment@97] - Server environment:host.name=slave-01
2012-01-08 06:51:23,207 - INFO [QuorumPeer:/0:0:0:0:0:0:0:0:2181:Environment@97] - Server environment:java.version=1.6.0_30
2012-01-08 06:51:23,208 - INFO [QuorumPeer:/0:0:0:0:0:0:0:0:2181:Environment@97] - Server environment:java.vendor=Sun Microsystems Inc.
2012-01-08 06:51:23,208 - INFO [QuorumPeer:/0:0:0:0:0:0:0:0:2181:Environment@97] - Server environment:java.home=/home/hadoop/installation/jdk1.6.0_30/jre
2012-01-08 06:51:23,209 - INFO [QuorumPeer:/0:0:0:0:0:0:0:0:2181:Environment@97] - Server environment:java.class.path=/home/hadoop/installation/zookeeper-3.3.4/bin/../build/classes:/home/hadoop/installation/zookeeper-3.3.4/bin/../build/lib/*.jar:/home/hadoop/installation/zookeeper-3.3.4/bin/../zookeeper-3.3.4.jar:/home/hadoop/installation/zookeeper-3.3.4/bin/../lib/log4j-1.2.15.jar:/home/hadoop/installation/zookeeper-3.3.4/bin/../lib/jline-0.9.94.jar:/home/hadoop/installation/zookeeper-3.3.4/bin/../lib/commons-lang-2.4.jar:/home/hadoop/installation/zookeeper-3.3.4/bin/../lib/commons-collections-3.2.jar:/home/hadoop/installation/zookeeper-3.3.4/bin/../lib/commons-cli-1.1.jar:/home/hadoop/installation/zookeeper-3.3.4/bin/../lib/apache-rat-tasks-0.6.jar:/home/hadoop/installation/zookeeper-3.3.4/bin/../lib/apache-rat-core-0.6.jar:/home/hadoop/installation/zookeeper-3.3.4/bin/../src/java/lib/*.jar:/home/hadoop/installation/zookeeper-3.3.4/bin/../conf:/home/hadoop/installation/jdk1.6.0_30/lib/*.jar:/home/hadoop/installation/jdk1.6.0_30/jre/lib/*.jar
2012-01-08 06:51:23,210 - INFO [QuorumPeer:/0:0:0:0:0:0:0:0:2181:Environment@97] - Server environment:java.library.path=/home/hadoop/installation/jdk1.6.0_30/jre/lib/i386/client:/home/hadoop/installation/jdk1.6.0_30/jre/lib/i386:/home/hadoop/installation/jdk1.6.0_30/jre/../lib/i386:/usr/java/packages/lib/i386:/lib:/usr/lib
2012-01-08 06:51:23,210 - INFO [QuorumPeer:/0:0:0:0:0:0:0:0:2181:Environment@97] - Server environment:java.io.tmpdir=/tmp
2012-01-08 06:51:23,212 - INFO [QuorumPeer:/0:0:0:0:0:0:0:0:2181:Environment@97] - Server environment:java.compiler=<NA>
2012-01-08 06:51:23,212 - INFO [QuorumPeer:/0:0:0:0:0:0:0:0:2181:Environment@97] - Server environment:os.name=Linux
2012-01-08 06:51:23,212 - INFO [QuorumPeer:/0:0:0:0:0:0:0:0:2181:Environment@97] - Server environment:os.arch=i386
2012-01-08 06:51:23,213 - INFO [QuorumPeer:/0:0:0:0:0:0:0:0:2181:Environment@97] - Server environment:os.version=3.0.0-14-generic
2012-01-08 06:51:23,213 - INFO [QuorumPeer:/0:0:0:0:0:0:0:0:2181:Environment@97] - Server environment:user.name=hadoop
2012-01-08 06:51:23,214 - INFO [QuorumPeer:/0:0:0:0:0:0:0:0:2181:Environment@97] - Server environment:user.home=/home/hadoop
2012-01-08 06:51:23,214 - INFO [QuorumPeer:/0:0:0:0:0:0:0:0:2181:Environment@97] - Server environment:user.dir=/home/hadoop/installation/zookeeper-3.3.4
2012-01-08 06:51:23,223 - INFO [QuorumPeer:/0:0:0:0:0:0:0:0:2181:ZooKeeperServer@151] - Created server with tickTime 2000 minSessionTimeout 4000 maxSessionTimeout 40000 datadir /home/hadoop/storage/zookeeper/version-2 snapdir /home/hadoop/storage/zookeeper/version-2
2012-01-08 06:51:23,339 - INFO [QuorumPeer:/0:0:0:0:0:0:0:0:2181:Learner@294] - Getting a snapshot from leader
2012-01-08 06:51:23,358 - INFO [QuorumPeer:/0:0:0:0:0:0:0:0:2181:Learner@325] - Setting leader epoch 1
2012-01-08 06:51:23,358 - INFO [QuorumPeer:/0:0:0:0:0:0:0:0:2181:FileTxnSnapLog@254] - Snapshotting: 0
2012-01-08 06:51:25,511 - INFO [WorkerReceiver Thread:FastLeaderElection@496] - Notification: 3 (n.leader), 0 (n.zxid), 1 (n.round), LOOKING (n.state), 3 (n.sid), FOLLOWING (my state)
2012-01-08 06:51:42,584 - INFO [WorkerReceiver Thread:FastLeaderElection@496] - Notification: 3 (n.leader), 0 (n.zxid), 2 (n.round), LOOKING (n.state), 3 (n.sid), FOLLOWING (my state)
我启动的顺序是slave-01>slave-02>slave-03,因为ZooKeeper集群启动的时候,每一个结点都试图去链接集群中的其它结点,先启动的确定连不上后面还没启动的,因此上面日志前面部分的异常是能够忽略的。经过后面部分能够看到,集群在选出一个Leader后,最后稳定了。
其余结点可能也出现相似问题,属于正常。
第六步:安装验证
能够经过ZooKeeper的脚原本查看启动状态,包括集群中各个结点的角色(或是Leader,或是Follower),以下所示,是在ZooKeeper集群中的每一个结点上查询的结果:
[plain] view plaincopy
hadoop@slave-01:~/installation/zookeeper-3.3.4$ bin/zkServer.sh status
JMX enabled by default
Using config: /home/hadoop/installation/zookeeper-3.3.4/bin/../conf/zoo.cfg
Mode: follower
hadoop@slave-02:~/installation/zookeeper-3.3.4$ bin/zkServer.sh status
JMX enabled by default
Using config: /home/hadoop/installation/zookeeper-3.3.4/bin/../conf/zoo.cfg
Mode: leader
hadoop@slave-03:~/installation/zookeeper-3.3.4$ bin/zkServer.sh status
JMX enabled by default
Using config: /home/hadoop/installation/zookeeper-3.3.4/bin/../conf/zoo.cfg
Mode: follower
经过上面状态查询结果可见,slave-02是集群的Leader,其他的两个结点是Follower。
另外,能够经过客户端脚本,链接到ZooKeeper集群上。对于客户端来讲,ZooKeeper是一个总体(ensemble),链接到ZooKeeper集群实际上感受在独享整个集群的服务,因此,你能够在任何一个结点上创建到服务集群的链接,例如:
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hadoop@slave-03:~/installation/zookeeper-3.3.4$ bin/zkCli.sh -server slave-01:2181
Connecting to slave-01:2181
2012-01-08 07:14:21,068 - INFO [main:Environment@97] - Client environment:zookeeper.version=3.3.3-1203054, built on 11/17/2011 05:47 GMT
2012-01-08 07:14:21,080 - INFO [main:Environment@97] - Client environment:host.name=slave-03
2012-01-08 07:14:21,085 - INFO [main:Environment@97] - Client environment:java.version=1.6.0_30
2012-01-08 07:14:21,089 - INFO [main:Environment@97] - Client environment:java.vendor=Sun Microsystems Inc.
2012-01-08 07:14:21,095 - INFO [main:Environment@97] - Client environment:java.home=/home/hadoop/installation/jdk1.6.0_30/jre
2012-01-08 07:14:21,104 - INFO [main:Environment@97] - Client environment:java.class.path=/home/hadoop/installation/zookeeper-3.3.4/bin/../build/classes:/home/hadoop/installation/zookeeper-3.3.4/bin/../build/lib/*.jar:/home/hadoop/installation/zookeeper-3.3.4/bin/../zookeeper-3.3.4.jar:/home/hadoop/installation/zookeeper-3.3.4/bin/../lib/log4j-1.2.15.jar:/home/hadoop/installation/zookeeper-3.3.4/bin/../lib/jline-0.9.94.jar:/home/hadoop/installation/zookeeper-3.3.4/bin/../lib/commons-lang-2.4.jar:/home/hadoop/installation/zookeeper-3.3.4/bin/../lib/commons-collections-3.2.jar:/home/hadoop/installation/zookeeper-3.3.4/bin/../lib/commons-cli-1.1.jar:/home/hadoop/installation/zookeeper-3.3.4/bin/../lib/apache-rat-tasks-0.6.jar:/home/hadoop/installation/zookeeper-3.3.4/bin/../lib/apache-rat-core-0.6.jar:/home/hadoop/installation/zookeeper-3.3.4/bin/../src/java/lib/*.jar:/home/hadoop/installation/zookeeper-3.3.4/bin/../conf:/home/hadoop/installation/jdk1.6.0_30/lib/*.jar:/home/hadoop/installation/jdk1.6.0_30/jre/lib/*.jar
2012-01-08 07:14:21,111 - INFO [main:Environment@97] - Client environment:java.library.path=/home/hadoop/installation/jdk1.6.0_30/jre/lib/i386/client:/home/hadoop/installation/jdk1.6.0_30/jre/lib/i386:/home/hadoop/installation/jdk1.6.0_30/jre/../lib/i386:/usr/java/packages/lib/i386:/lib:/usr/lib
2012-01-08 07:14:21,116 - INFO [main:Environment@97] - Client environment:java.io.tmpdir=/tmp
2012-01-08 07:14:21,124 - INFO [main:Environment@97] - Client environment:java.compiler=<NA>
2012-01-08 07:14:21,169 - INFO [main:Environment@97] - Client environment:os.name=Linux
2012-01-08 07:14:21,175 - INFO [main:Environment@97] - Client environment:os.arch=i386
2012-01-08 07:14:21,177 - INFO [main:Environment@97] - Client environment:os.version=3.0.0-14-generic
2012-01-08 07:14:21,185 - INFO [main:Environment@97] - Client environment:user.name=hadoop
2012-01-08 07:14:21,188 - INFO [main:Environment@97] - Client environment:user.home=/home/hadoop
2012-01-08 07:14:21,190 - INFO [main:Environment@97] - Client environment:user.dir=/home/hadoop/installation/zookeeper-3.3.4
2012-01-08 07:14:21,197 - INFO [main:ZooKeeper@379] - Initiating client connection, connectString=slave-01:2181 sessionTimeout=30000 watcher=org.apache.zookeeper.ZooKeeperMain$MyWatcher@bf32c
2012-01-08 07:14:21,305 - INFO [main-SendThread():ClientCnxn$SendThread@1061] - Opening socket connection to server slave-01/192.168.0.179:2181
Welcome to ZooKeeper!
2012-01-08 07:14:21,376 - INFO [main-SendThread(slave-01:2181):ClientCnxn$SendThread@950] - Socket connection established to slave-01/192.168.0.179:2181, initiating session
JLine support is enabled
[zk: slave-01:2181(CONNECTING) 0] 2012-01-08 07:14:21,872 - INFO [main-SendThread(slave-01:2181):ClientCnxn$SendThread@739] - Session establishment complete on server slave-01/192.168.0.179:2181, sessionid = 0x134bdcd6b730000, negotiated timeout = 30000
WATCHER::
WatchedEvent state:SyncConnected type:None path:null
[zk: slave-01:2181(CONNECTED) 0] ls /
[zookeeper]
当前根路径为/zookeeper。
主机名与IP地址映射配置问题
启动ZooKeeper集群时,若是ZooKeeper集群中slave-01结点的日志出现以下错误:
[plain] view plaincopy
java.net.SocketTimeoutException
at sun.nio.ch.SocketAdaptor.connect(SocketAdaptor.java:109)
at org.apache.zookeeper.server.quorum.QuorumCnxManager.connectOne(QuorumCnxManager.java:371)
at org.apache.zookeeper.server.quorum.QuorumCnxManager.connectAll(QuorumCnxManager.java:404)
at org.apache.zookeeper.server.quorum.FastLeaderElection.lookForLeader(FastLeaderElection.java:688)
at org.apache.zookeeper.server.quorum.QuorumPeer.run(QuorumPeer.java:622)
2012-01-08 06:37:46,026 - INFO [QuorumPeer:/0:0:0:0:0:0:0:0:2181:FastLeaderElection@697] - Notification time out: 6400
2012-01-08 06:37:57,431 - WARN [QuorumPeer:/0:0:0:0:0:0:0:0:2181:QuorumCnxManager@384] - Cannot open channel to 2 at election address slave-02/202.106.199.35:3888
java.net.SocketTimeoutException
at sun.nio.ch.SocketAdaptor.connect(SocketAdaptor.java:109)
at org.apache.zookeeper.server.quorum.QuorumCnxManager.connectOne(QuorumCnxManager.java:371)
at org.apache.zookeeper.server.quorum.QuorumCnxManager.connectAll(QuorumCnxManager.java:404)
at org.apache.zookeeper.server.quorum.FastLeaderElection.lookForLeader(FastLeaderElection.java:688)
at org.apache.zookeeper.server.quorum.QuorumPeer.run(QuorumPeer.java:622)
2012-01-08 06:38:02,442 - WARN [QuorumPeer:/0:0:0:0:0:0:0:0:2181:QuorumCnxManager@384] - Cannot open channel to 3 at election address slave-03/202.106.199.35:3888
很显然,slave-01在启动时链接集群中其余结点(slave-0二、slave-03)时,主机名映射的IP与咱们实际配置的不一致,因此集群中各个结点之间没法创建链路,整个ZooKeeper集群启动是失败的。
上面错误日志中slave-02/202.106.199.35:3888实际应该是slave-02/202.192.168.0.178:3888就对了,可是在进行域名解析的时候映射有问题,修改每一个结点的/etc/hosts文件,将ZooKeeper集群中全部结点主机名到IP地址的映射配置上。
本文出自http://www.blogjava.net/hello-yun/archive/2012/05/03/377250.html