單機僞分布式安裝ZK叢集
1. ZK叢集搭建注意點
- 配置資料檔案
myid 1/2/3
server.1/2/3
- 通過
./zjCli.sh -server [ip]:[port]
2. ZK叢集的安裝過程
- 首先要拷貝2份ZK，現在系統中有3份ZK
-
其次要修改 /conf/zoo.cfg 檔案，一共修改3個位置。
- 然後在 /bin/目錄下
./zkServer.sh start
./zkServer.sh status
三台實體機（虛拟機）安裝ZK叢集
這裡有一個無知坑。。。。
首先我在虛拟機上克隆了兩個centOS系統，現在一共有3個centOS系統。
這三個系統中分别裝了zookeeper，分别代表 server1、server2 和 server3。
配置檔案如下：
主要是框住的3個位置，第一個位置中需要建立一個myid檔案，該檔案中的值對應server.x的x。即如果myid中的值為1，那麼對應的是server.1這個節點。因為是真機叢集，是以這裡的ClientPort都設定為一樣的值，這裡隻有server.x中的ip不一樣即可，剩下的配置都一樣。
server.A=B：C：D
server.1=192.168.41.129:2888:3888
server.2=192.168.41.132:2888:3888
server.3=192.168.41.133:2888:3888
A 是一個數字,表示這個是第幾号伺服器；
B 是這個伺服器的 IP 位址（或者是與 IP 位址做了映射的主機名，如果寫的是主機名需要在hosts中配置一下） ；
C 第一個端口用來叢集成員的資訊交換,表示這個伺服器與叢集中的 Leader 伺服器交換資訊的端口；
D 是在 leader 挂掉時專門用來進行選舉 leader 所用的端口。
注意：如果是僞叢集的配置方式，不同的 Zookeeper 執行個體通信端口号不能一樣，是以要給它們配置設定不同的端口号。
這樣就配置完成了，接下來，我們說一下我遇到的坑~~~~
在配置好後，在zookeeper/bin檔案夾下，運作zkServer.sh start指令，會報錯。
2019-01-11 17:15:03,776 [myid:] - INFO [main-SendThread(localhost:2181):[email protected]] - Opening socket connection to server localhost/127.0.0.1:2181. Will not attempt to authenticate using SASL (unknown error)
2019-01-11 17:15:03,777 [myid:] - INFO [main-SendThread(localhost:2181):[email protected]] - Socket connection established to localhost/127.0.0.1:2181, initiating session
2019-01-11 17:15:03,778 [myid:] - INFO [main-SendThread(localhost:2181):[email protected]] - Unable to read additional data from server sessionid 0x300001555fd0000, likely server has closed socket, closing socket connection and attempting reconnect
2019-01-11 17:15:05,726 [myid:] - INFO [main-SendThread(localhost:2181):[email protected]] - Opening socket connection to server localhost/0:0:0:0:0:0:0:1:2181. Will not attempt to authenticate using SASL (unknown error)
2019-01-11 17:15:05,729 [myid:] - INFO [main-SendThread(localhost:2181):[email protected]] - Socket connection established to localhost/0:0:0:0:0:0:0:1:2181, initiating session
2019-01-11 17:15:05,734 [myid:] - INFO [main-SendThread(localhost:2181):[email protected]] - Unable to read additional data from server sessionid 0x300001555fd0000, likely server has closed socket, closing socket connection and attempting reconnect
2019-01-11 17:15:06,043 [myid:] - INFO [main-SendThread(localhost:2181):[email protected]] - Opening socket connection to server localhost/127.0.0.1:2181. Will not attempt to authenticate using SASL (unknown error)
2019-01-11 17:15:06,044 [myid:] - INFO [main-SendThread(localhost:2181):[email protected]] - Socket connection established to localhost/127.0.0.1:2181, initiating session
2019-01-11 17:15:06,045 [myid:] - INFO [main-SendThread(localhost:2181):[email protected]] - Unable to read additional data from server sessionid 0x300001555fd0000, likely server has closed socket, closing socket connection and attempting reconnect
2019-01-11 17:15:07,215 [myid:] - INFO [main-SendThread(localhost:2181):[email protected]] - Opening socket connection to server localhost/0:0:0:0:0:0:0:1:2181. Will not attempt to authenticate using SASL (unknown error)
2019-01-11 17:15:07,216 [myid:] - INFO [main-SendThread(localhost:2181):[email protected]] - Socket connection established to localhost/0:0:0:0:0:0:0:1:2181, initiating session
2019-01-11 17:15:07,217 [myid:] - INFO [main-SendThread(localhost:2181):[email protected]] - Unable to read additional data from server sessionid 0x300001555fd0000, likely server has closed socket, closing socket connection and attempting reconnect
2019-01-11 17:15:07,883 [myid:] - INFO [main-SendThread(localhost:2181):[email protected]] - Opening socket connection to server localhost/127.0.0.1:2181. Will not attempt to authenticate using SASL (unknown error)
2019-01-11 17:15:07,883 [myid:] - INFO [main-SendThread(localhost:2181):[email protected]] - Socket connection established to localhost/127.0.0.1:2181, initiating session
2019-01-11 17:15:07,887 [myid:] - INFO [main-SendThread(localhost:2181):[email protected]] - Unable to read additional data from server sessionid 0x300001555fd0000, likely server has closed socket, closing socket connection and attempting reconnect
2019-01-11 17:15:09,678 [myid:] - INFO [main-SendThread(localhost:2181):[email protected]] - Opening socket connection to server localhost/0:0:0:0:0:0:0:1:2181. Will not attempt to authenticate using SASL (unknown error)
2019-01-11 17:15:09,681 [myid:] - INFO [main-SendThread(localhost:2181):[email protected]] - Socket connection established to localhost/0:0:0:0:0:0:0:1:2181, initiating session
這個問題查了好久部落格都沒有搞定，把防火牆關了也不好使，自己以為是配置出現了問題，是以看了很多遍别人的配置部落格，都要看爛了，後來把配置檔案zoo.cfg的server節點注釋掉，發現可以正常啟動，是以就定位到了一定是叢集的問題，然後後來找到了另一篇博文，終于解決了這個問題。
因為在zoo.cfg中配置了三台機器，但是隻啟動了1台機器，ZK就會任務服務處于不可用的狀态。是以當你把所有機器都起來的時候，在運作用戶端就可以了。
ZK有一個選舉算法，當整個叢集超過半數機器當機，ZK就會認為叢集處于不可用的狀态。
參考并感謝
https://www.cnblogs.com/showxiaxian/p/4528590.html