一、下載
https://mirrors.tuna.tsinghua.edu.cn/apache/zookeeper/
二、安裝
前提：安裝jdk
解壓縮 zookeeper 安裝包
mkdir zookeeper
cd zookeeper/
tar -zxvf apache-zookeeper-3.6.1-bin.tar.gz
進入conf目錄，cp生成一個zk能識別的配置文件名：zoo.cfg
cd apache-zookeeper-3.6.1-bin/conf/
cp zoo_sample.cfg zoo.cfg
修改配置文件zoo.cfg
vi zoo.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=/data/zookeeper
# 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
## Metrics Providers
#
# https://prometheus.io Metrics Exporter
#metricsProvider.className=org.apache.zookeeper.metrics.prometheus.PrometheusMetricsProvider
#metricsProvider.httpPort=7000
#metricsProvider.exportJvmInfo=true
三、啓動Zookeeper
3.1、啓動節點
默認會到同級目錄conf中尋找zoo.cfg文件，所以默認不用加配置文件
./zkServer.sh start
如果啓動報錯，提示
: 找不到或無法加載主類 org.apache.zookeeper.server.quorum.QuorumPeerMain
zookeeper在3.5.5之後在下載的時候應該下載帶bin的文件，而之前的普通的tar.gz的包裏面是隻是源碼的包無法直接使用。
3.2、查看節點狀態
./zkServer.sh status
3.2、關閉節點
./zkServer.sh stop
四、集羣安裝Zookeeper
Zookeeper節點部署越多，服務的可靠性越高，建議部署奇數個節點，因爲zookeeper集羣是以
宕機個數過半纔會讓整個集羣宕機的。
| ip | myid | 節點 |
|---|---|---|
| 192.168.1.200 | 1 | 節點1 |
| 192.168.1.201 | 2 | 節點2 |
| 192.168.1.202 | 3 | 節點3 |
分別在三臺服務器上安裝Zookeeper服務，步驟按照上述即可
4.1、修改配置文件zoo.cfg
三臺zoo.cfg文件內容一致
server.1=192.168.1.200:2888:3888
server.2=192.168.1.201:2889:3889
server.3=192.168.1.202:2890:3890
4.2、添加myid文件
集羣模式下需要添加myid文件，保存路徑爲zoo.cfg文件下dataDir=/data/zookeeper路徑下
myid文件內容爲zoo.cfg文件中server.x，即對應（1，2，3），zookeeper會根據myid文件內容，判斷那個是server（節點）
cd /data/zookeeper/
分別爲1，2，3
vi myid
1
vi myid
2
vi myid
3
4.3、啓動集羣
三臺zk服務器分別執行啓動命令
cd /usr/local/zookeeper/apache-zookeeper-3.6.1-bin/bin/
./zkServer.sh start
查看日誌，發現啓動失敗
cd ..
tail -f logs/zookeeper-root-server-192.168.1.200.out
2020-06-14 21:54:44,540 [myid:2] - WARN [QuorumConnectionThread-[myid=2]-2:QuorumCnxManager@400] - Cannot open channel to 3 at election address /192.168.1.202:3890
java.net.NoRouteToHostException: 沒有到主機的路由 (Host unreachable)
at java.net.PlainSocketImpl.socketConnect(Native Method)
at java.net.AbstractPlainSocketImpl.doConnect(AbstractPlainSocketImpl.java:350)
at java.net.AbstractPlainSocketImpl.connectToAddress(AbstractPlainSocketImpl.java:206)
at java.net.AbstractPlainSocketImpl.connect(AbstractPlainSocketImpl.java:188)
at java.net.SocksSocketImpl.connect(SocksSocketImpl.java:392)
at java.net.Socket.connect(Socket.java:589)
at org.apache.zookeeper.server.quorum.QuorumCnxManager.initiateConnection(QuorumCnxManager.java:383)
at org.apache.zookeeper.server.quorum.QuorumCnxManager$QuorumConnectionReqThread.run(QuorumCnxManager.java:457)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
at java.lang.Thread.run(Thread.java:748)
原因，防火牆未關閉導致
systemctl stop firewalld.service #停止firewall
systemctl disable firewalld.service #禁止firewall開機啓動
firewall-cmd --state #查看默認防火牆狀態（關閉後顯示notrunning，開啓後顯示running）
查看節點狀態
./zkServer.sh status
200服務器
#從節點
Mode: follower
201服務器
#從節點
Mode: follower
202服務器
#主節點
Mode: leader
五、zookeeper角色、狀態介紹
在zookeeper的集羣中，節點具有3種角色、4種狀態
角色：leader,follower,observer
狀態：leading,following,observing,looking
leading：當前Server即爲選舉出來的leader。
following：已經選舉出來，當前Server與之同步。
observing：的行爲在大多數情況下與follower完全一致，但是他們不參加選舉和投票，而僅僅接受(observing)選舉和投票的結果。
looking：當前Server不知道leader是誰，正在搜尋。
六、設置開機自啓
cd /etc/rc.d/init.d/
#創建zookeeper文件
vi zookeeper
編寫腳本
#!/bin/bash
#chkconfig: 2345 80 90
#description:zookeeper
#processname:zookeeper
export JAVA_HOME=/usr/java/jdk1.8.0_191
case $1 in
start) su root /usr/local/zookeeper/apache-zookeeper-3.6.1-bin/bin/zkServer.sh start;;
stop) su root /usr/local/zookeeper/apache-zookeeper-3.6.1-bin/bin/zkServer.sh stop;;
status) su root /usr/local/zookeeper/apache-zookeeper-3.6.1-bin/bin/zkServer.sh status;;
restart) su root /usr/local/zookeeper/apache-zookeeper-3.6.1-bin/bin/zkServer.sh restart;;
*) echo "require start|stop|status|restart" ;;
esac
#給文件添加權限
chmod +x zookeeper
#配置開機啓動項
chkconfig --add zookeeper
#查看zk配置是否成功
chkconfig --list
#重啓服務器測試是否成功
reboot