【zookeeper】zookeeper单机和集群环境的搭建
首先去官网下载zookeeper安装包，本文采用3.4.6stable版本
http://zookeeper.apache.org/doc/r3.4.6/
tar命令解压后的目录结构如下：
[root@com23 zookeeper-3.4.6]# ll total 1612 drwxr-xr-x 2 1000 1000 4096 Feb 20 2014 bin -rw-rw-r-- 1 1000 1000 82446 Feb 20 2014 build.xml -rw-rw-r-- 1 1000 1000 80776 Feb 20 2014 CHANGES.txt drwxr-xr-x 2 1000 1000 4096 Jan 22 11:39 conf drwxr-xr-x 10 1000 1000 4096 Feb 20 2014 contrib drwxr-xr-x 2 1000 1000 4096 Feb 20 2014 dist-maven drwxr-xr-x 6 1000 1000 4096 Feb 20 2014 docs -rw-rw-r-- 1 1000 1000 1953 Feb 20 2014 ivysettings.xml -rw-rw-r-- 1 1000 1000 3375 Feb 20 2014 ivy.xml drwxr-xr-x 4 1000 1000 4096 Feb 20 2014 lib -rw-rw-r-- 1 1000 1000 11358 Feb 20 2014 LICENSE.txt -rw-rw-r-- 1 1000 1000 170 Feb 20 2014 NOTICE.txt -rw-rw-r-- 1 1000 1000 1770 Feb 20 2014 README_packaging.txt -rw-rw-r-- 1 1000 1000 1585 Feb 20 2014 README.txt drwxr-xr-x 5 1000 1000 4096 Feb 20 2014 recipes drwxr-xr-x 8 1000 1000 4096 Feb 20 2014 src -rw-rw-r-- 1 1000 1000 1340305 Feb 20 2014 zookeeper-3.4.6.jar -rw-rw-r-- 1 1000 1000 836 Feb 20 2014 zookeeper-3.4.6.jar.asc -rw-rw-r-- 1 1000 1000 33 Feb 20 2014 zookeeper-3.4.6.jar.md5 -rw-rw-r-- 1 1000 1000 41 Feb 20 2014 zookeeper-3.4.6.jar.sha1 -rw-r--r-- 1 root root 46852 Jan 22 11:42 zookeeper.out我们进入conf目录下新建zoo.cfg配置文件，文件名随便都行，但是默认是这个文件名，为什么呢？
看zkEnv.sh就知道了
if [ "x$ZOOCFG" = "x" ]
then
ZOOCFG="zoo.cfg"
fi
1、单机模式
文件内容如下：#the basic time unit in milliseconds used by zookeeper,it is used to do heartbeats and the min session timeout will be twice the tickTime tickTime=2000 #the location to store the in-memory database snapshots and ,unless specified otherwise,the transaction log of updates to database dataDir=/home/zookeeper/zkData #the port to listen for client connections clientPort=2181至此，单机配置就结束了，下面可以启动了
bin/zkServer.sh start启动完成后，通过如下命令连接上去：
bin/zkCli.sh -server serverIp:2181当然你的客户端肯定要装个zk啦
[zk: localhost:2181(CONNECTED) 27] ll
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至此，单机模式就结束了！
2、集群模式
修改配置文件如下：
#the basic time unit in milliseconds used by zookeeper,it is used to do heartbeats and the min session timeout will be twice the tickTime tickTime=2000 #the location to store the in-memory database snapshots and ,unless specified otherwise,the transaction log of updates to database dataDir=/home/zookeeper/zkData #the port to listen for client connections clientPort=2181 #timeouts zookeeper uses to limit the length of time the zookeeper servers in quorum have to connect to a leader initLimit=5 #limits how far out of date a server can be from a leader syncLimit=2 #With both of above timeouts, you specify the unit of time using tickTime. In this example, the timeout for initLimit is 5 ticks at 2000 milleseconds a tick, or 10 seconds. server.1=192.168.11.176:2888:3888 server.2=192.168.11.177:2888:3888 server.3=192.168.11.178:2888:3888The entries of the form server.X list the servers that make up the ZooKeeper service. When the server starts up, it knows which server it is by looking for the file myid in the data directory. That file has the contains the server number, in ASCII.
这句话的意思，server.X中的x是从dataDir路径下的myid文件来读取的，所以我们要创建相应的myid文件，内容分别是1，2，3
至此，集群的配置已经完成了！
下面到各个节点机器上去启动zookeeper
sh bin/zkServer.sh start可以去看zookeeper.out的启动日志输出
查看节点状态
[root@com23 zookeeper-3.4.6]# sh bin/zkServer.sh status JMX enabled by default Using config: /home/zookeeper/zookeeper-3.4.6/bin/../conf/zoo.cfg Mode: leader
[root@com22 zookeeper-3.4.6]# sh bin/zkServer.sh status JMX enabled by default Using config: /home/zookeeper/zookeeper-3.4.6/bin/../conf/zoo.cfg Mode: follower
[root@com21 zookeeper-3.4.6]# sh bin/zkServer.sh status JMX enabled by default Using config: /home/zookeeper/zookeeper-3.4.6/bin/../conf/zoo.cfg Mode: follower三个节点，一个leader，两个follower
这里补充一点：zookeeper的集群必须得奇数个节点，因为zookeeper有个机制，当集群中大于半数的节点挂了，整个zookeeper将停止服务，如果说是偶数台的话，一半对一半，zookeeper很难判断，所以zookeeper的集群建议偶数台搭建。
下面另起一个客户端去连接zk集群：
[root@com20 zookeeper-3.4.6]# sh bin/zkCli.sh -server 192.168.11.178:2181 Connecting to 192.168.11.178:2181 2015-01-22 14:41:08,947 [myid:] - INFO [main:Environment@100] - Client environment:zookeeper.version=3.4.6-1569965, built on 02/20/2014 09:09 GMT 2015-01-22 14:41:08,975 [myid:] - INFO [main:Environment@100] - Client environment:host.name=com20.authentication 2015-01-22 14:41:08,975 [myid:] - INFO [main:Environment@100] - Client environment:java.version=1.7.0_60 2015-01-22 14:41:08,989 [myid:] - INFO [main:Environment@100] - Client environment:java.vendor=Oracle Corporation 2015-01-22 14:41:08,990 [myid:] - INFO [main:Environment@100] - Client environment:java.home=/usr/java/jdk1.7.0_67/jre 2015-01-22 14:41:08,991 [myid:] - INFO [main:Environment@100] - Client environment:java.class.path=/home/zookeeper/zookeeper-3.4.6/bin/../build/classes:/home/zookeeper/zookeeper-3.4.6/bin/../build/lib/*.jar:/home/zookeeper/zookeeper-3.4.6/bin/../lib/slf4j-log4j12-1.6.1.jar:/home/zookeeper/zookeeper-3.4.6/bin/../lib/slf4j-api-1.6.1.jar:/home/zookeeper/zookeeper-3.4.6/bin/../lib/netty-3.7.0.Final.jar:/home/zookeeper/zookeeper-3.4.6/bin/../lib/log4j-1.2.16.jar:/home/zookeeper/zookeeper-3.4.6/bin/../lib/jline-0.9.94.jar:/home/zookeeper/zookeeper-3.4.6/bin/../zookeeper-3.4.6.jar:/home/zookeeper/zookeeper-3.4.6/bin/../src/java/lib/*.jar:/home/zookeeper/zookeeper-3.4.6/bin/../conf:.:/usr/java/jdk1.7.0_67/lib:/usr/java/jdk1.7.0_67/lib/tools.jar:/usr/java/jdk1.7.0_67/lib/dt.jar:/usr/java/jdk1.7.0_67/jre/lib:/usr/java/jdk1.7.0_67/jre/lib/charsets.jar:/usr/java/jdk1.7.0_67/jre/lib/rt.jar 2015-01-22 14:41:08,991 [myid:] - INFO [main:Environment@100] - Client environment:java.library.path=/usr/java/packages/lib/amd64:/usr/lib64:/lib64:/lib:/usr/lib 2015-01-22 14:41:08,992 [myid:] - INFO [main:Environment@100] - Client environment:java.io.tmpdir=/tmp 2015-01-22 14:41:08,993 [myid:] - INFO [main:Environment@100] - Client environment:java.compiler=<NA> 2015-01-22 14:41:08,993 [myid:] - INFO [main:Environment@100] - Client environment:os.name=Linux 2015-01-22 14:41:08,994 [myid:] - INFO [main:Environment@100] - Client environment:os.arch=amd64 2015-01-22 14:41:08,995 [myid:] - INFO [main:Environment@100] - Client environment:os.version=2.6.18-308.el5 2015-01-22 14:41:08,995 [myid:] - INFO [main:Environment@100] - Client environment:user.name=root 2015-01-22 14:41:08,996 [myid:] - INFO [main:Environment@100] - Client environment:user.home=/root 2015-01-22 14:41:08,996 [myid:] - INFO [main:Environment@100] - Client environment:user.dir=/home/zookeeper/zookeeper-3.4.6 2015-01-22 14:41:09,000 [myid:] - INFO [main:ZooKeeper@438] - Initiating client connection, connectString=192.168.11.178:2181 sessionTimeout=30000 watcher=org.apache.zookeeper.ZooKeeperMain$MyWatcher@8afbefd Welcome to ZooKeeper! 2015-01-22 14:41:09,187 [myid:] - INFO [main-SendThread(192.168.11.178:2181):ClientCnxn$SendThread@975] - Opening socket connection to server 192.168.11.178/192.168.11.178:2181. Will not attempt to authenticate using SASL (unknown error) JLine support is enabled 2015-01-22 14:41:09,243 [myid:] - INFO [main-SendThread(192.168.11.178:2181):ClientCnxn$SendThread@852] - Socket connection established to 192.168.11.178/192.168.11.178:2181, initiating session [zk: 192.168.11.178:2181(CONNECTING) 0] 2015-01-22 14:41:09,481 [myid:] - INFO [main-SendThread(192.168.11.178:2181):ClientCnxn$SendThread@1235] - Session establishment complete on server 192.168.11.178/192.168.11.178:2181, sessionid = 0x34b1057cbfa0000, negotiated timeout = 30000 WATCHER:: WatchedEvent state:SyncConnected type:None path:null [zk: 192.168.11.178:2181(CONNECTED) 0] [zk: 192.168.11.178:2181(CONNECTED) 1] ls / [zookeeper, zk_test] [zk: 192.168.11.178:2181(CONNECTED) 2] get /zk_test my_data cZxid = 0x5 ctime = Thu Jan 22 13:52:58 CST 2015 mZxid = 0x5 mtime = Thu Jan 22 13:52:58 CST 2015 pZxid = 0x5 cversion = 0 dataVersion = 0 aclVersion = 0 ephemeralOwner = 0x0 dataLength = 7 numChildren = 0 [zk: 192.168.11.178:2181(CONNECTED) 3]如果你的客户端只是去连zk集群，只需要解压zk安装包即可，使用命令直接可以连接，无需任何配置！
如遇任何问题，建议大家去官网参考，官网的永远是权威！
http://zookeeper.apache.org/doc/r3.4.6/zookeeperStarted.html
共勉！