（2）. Module2 僞分佈式模式
上面演示瞭如何啓動單機模式，現在我們來演示設置僞分佈式模式。
我們可以在一臺機器上創建模擬的ZooKeeper集羣服務，假如我們需要3個節點，需要創建3個cfg文件，分別命名爲zoo1.cfg，zoo2.cfg，zoo3.cfg，此外我們還需要創建3個不同的數據文件夾，分別是zoo1，zoo2和zoo3，目錄位於/var/lib/zookeeper，如1-16、1-17和1-18三個配置清單所示。
清單1-16 配置文件zoo1內容
[root@localhost conf]# cat zoo1.cfg
# 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=/var/lib/zookeeper/zoo1
# the port at which the clients will connect
clientPort=2181
# the maximum number of client connections.
# increase this if you need to handle more clients
#maxClientCnxns=60
#
# 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
server.1=localhost:2666:3666
server.2=localhost:2667:3667
server.3=localhost:2668:3668
清單1-17 配置文件zoo2內容
[root@localhost conf]# cat zoo2.cfg
# 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=dataDir=/var/lib/zookeeper/zoo2
# the port at which the clients will connect
clientPort=2182
# the maximum number of client connections.
# increase this if you need to handle more clients
#maxClientCnxns=60
#
# 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
server.1=localhost:2666:3666
server.2=localhost:2667:3667
server.3=localhost:2668:3668
清單1-18 配置文件zoo3內容
[root@localhost conf]# cat zoo3.cfg
# 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=/var/lib/zookeeper/zoo3
# the port at which the clients will connect
clientPort=2183
# the maximum number of client connections.
# increase this if you need to handle more clients
#maxClientCnxns=60
#
# 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
server.1=localhost:2666:3666
server.2=localhost:2667:3667
server.3=localhost:2668:3668
注意，每一個虛擬機器都對應一個自己的zoo{$}.cfg，其中的{$}需要通過清單1-19所示命令來進行設置。
Tips 由於採用的是“>”，所以命令會創建文件，如果採用“>>”，則Linux會在原有文件基礎上新增內容。 |
清單1-19 設置myid
[root@localhost conf]# echo 1 > /var/lib/zookeeper/zoo1/myid
[root@localhost conf]# echo 2 > /var/lib/zookeeper/zoo2/myid
[root@localhost conf]# echo 3 > /var/lib/zookeeper/zoo3/myid
接下來我們開始啓動ZooKeeper的3個實例（虛擬的3臺機器），需要調用三次zkServer.sh的Start命令，採用不同的配置文件，如清單1-20所示命令及輸出。
清單1-20 啓動僞分佈式集羣服務
[root@localhost bin]# ./zkServer.sh start/home/zhoumingyao/zookeeper/zookeeper-3.4.7/conf/zoo1.cfg
ZooKeeper JMX enabled by default
Using config: /home/zhoumingyao/zookeeper/zookeeper-3.4.7/conf/zoo1.cfg
Starting zookeeper ... STARTED
[root@localhost bin]# ./zkServer.sh start/home/zhoumingyao/zookeeper/zookeeper-3.4.7/conf/zoo2.cfg
ZooKeeper JMX enabled by default
Using config: /home/zhoumingyao/zookeeper/zookeeper-3.4.7/conf/zoo2.cfg
Starting zookeeper ... STARTED
[root@localhost bin]# ./zkServer.sh start/home/zhoumingyao/zookeeper/zookeeper-3.4.7/conf/zoo3.cfg
ZooKeeper JMX enabled by default
Using config: /home/zhoumingyao/zookeeper/zookeeper-3.4.7/conf/zoo3.cfg
Starting zookeeper ... STARTED
清單1-21 查看服務
[root@localhost bin]# jps
5537 QuorumPeerMain
5617 Jps
5585 QuorumPeerMain
確認服務都正常啓動，我們就可以通過zkCli.sh腳本方式連接到ZooKeeper集羣，命令爲./zkCli.sh -server localhost:2181,localhost:2182,localhost:2183，效果和單機模式一樣。
