zookeeper僞分佈式配置與遇到的問題

　　zookeeper提供了單機、分佈式和僞分佈式三種模式。

#zookeeper的默認配置文件zoo.cfg：
tickTime=2000
initLimit=10
syncLimit=5
dataDir=/tmp/zookeeper
clientPort=2181

　　條件有限，以僞分佈式爲例，將zookeeper文件夾複製三份，基本配置以下：

#第一個
tickTime=2000
initLimit=5
syncLimit=2
#我本機的目錄
dataDir=D:/zookeeper/zookeeper-3.4.9-1/data
dataLogDir=D:/zookeeper/zookeeper-3.4.9-1/logs
clientPort=2181
server.1=localhost:7888:8888 
server.2=localhost:7889:8889 
server.3=localhost:7889:8890

#第二個
tickTime=2000
initLimit=5
syncLimit=2
#我本機的目錄
dataDir=D:/zookeeper/zookeeper-3.4.9-2/data
dataLogDir=D:/zookeeper/zookeeper-3.4.9-2/logs
clientPort=2182
server.1=localhost:7888:8888 
server.2=localhost:7889:8889 
server.3=localhost:7889:8890

#第三個
tickTime=2000
initLimit=5
syncLimit=2
#我本機的目錄
dataDir=D:/zookeeper/zookeeper-3.4.9-3/data
dataLogDir=D:/zookeeper/zookeeper-3.4.9-3/logs
clientPort=2183
server.1=localhost:7888:8888 
server.2=localhost:7889:8889 
server.3=localhost:7889:8890

　　僞分佈式和分佈式配置的區別在於，僞分佈式配置IP地址相同，端口號不一樣。

　　windows系統使用%zk_home%/bin目錄下的zkServer.cmd啓動zookeeper。因爲在僞分佈式下部署了三個節點，因此依次進入每一個文件夾中，啓動zookeeper。啓動的時候可能會報錯。

 1 2017-02-09 14:21:38,871 [myid:] - ERROR [main:QuorumPeerMain@85] - Invalid confi
 2 g, exiting abnormally
 3 org.apache.zookeeper.server.quorum.QuorumPeerConfig$ConfigException: Error proce
 4 ssing D:\zookeeper\zookeeper-3.4.9-1\bin\..\conf\zoo.cfg
 5         at org.apache.zookeeper.server.quorum.QuorumPeerConfig.parse(QuorumPeerC
 6 onfig.java:144)
 7         at org.apache.zookeeper.server.quorum.QuorumPeerMain.initializeAndRun(Qu
 8 orumPeerMain.java:101)
 9         at org.apache.zookeeper.server.quorum.QuorumPeerMain.main(QuorumPeerMain
10 .java:78)
11 Caused by: java.lang.IllegalArgumentException: D:\zookeeper\zookeeper-3.4.9-1\da
12 ta\myid file is missing
13         at org.apache.zookeeper.server.quorum.QuorumPeerConfig.parseProperties(Q
14 uorumPeerConfig.java:362)
15         at org.apache.zookeeper.server.quorum.QuorumPeerConfig.parse(QuorumPeerC
16 onfig.java:140)
17         ... 2 more
18 Invalid config, exiting abnormally

　　錯誤緣由是沒有找到myid這個文件（如十一、12行），須要在配置文件dataDir指定的目錄下面（個人是：D:\zookeeper\zookeeper-3.4.9-1\data）創建一個myid文件，內容爲1。依次在剩下的兩個文件夾中也創建一個myid的文件，內容分別爲2和3。

　　保存後，再次啓動，發現又出現異常了，異常比較多，僅截取部分：

 1 2017-02-09 14:32:32,467 [myid:1] - WARN  [QuorumPeer[myid=1]/0:0:0:0:0:0:0:0:218
 2 1:QuorumCnxManager@400] - Cannot open channel to 3 at election address localhost
 3 /127.0.0.1:8890
 4 java.net.ConnectException: Connection refused: connect
 5         at java.net.DualStackPlainSocketImpl.waitForConnect(Native Method)
 6         at java.net.DualStackPlainSocketImpl.socketConnect(DualStackPlainSocketI
 7 mpl.java:85)
 8         at java.net.AbstractPlainSocketImpl.doConnect(AbstractPlainSocketImpl.ja
 9 va:350)
10         at java.net.AbstractPlainSocketImpl.connectToAddress(AbstractPlainSocket
11 Impl.java:206)
12         at java.net.AbstractPlainSocketImpl.connect(AbstractPlainSocketImpl.java
13 :188)
14         at java.net.PlainSocketImpl.connect(PlainSocketImpl.java:172)
15         at java.net.SocksSocketImpl.connect(SocksSocketImpl.java:392)
16         at java.net.Socket.connect(Socket.java:589)
17         at org.apache.zookeeper.server.quorum.QuorumCnxManager.connectOne(Quorum
18 CnxManager.java:381)
19         at org.apache.zookeeper.server.quorum.QuorumCnxManager.connectAll(Quorum
20 CnxManager.java:426)
21         at org.apache.zookeeper.server.quorum.FastLeaderElection.lookForLeader(F
22 astLeaderElection.java:843)
23         at org.apache.zookeeper.server.quorum.QuorumPeer.run(QuorumPeer.java:822
24 )
25 2017-02-09 14:32:32,623 [myid:1] - INFO  [QuorumPeer[myid=1]/0:0:0:0:0:0:0:0:218
26 1:QuorumPeer$QuorumServer@149] - Resolved hostname: localhost to address: localh
27 ost/127.0.0.1
28 2017-02-09 14:32:32,623 [myid:1] - INFO  [QuorumPeer[myid=1]/0:0:0:0:0:0:0:0:218
29 1:FastLeaderElection@852] - Notification time out: 12800
30 2017-02-09 14:32:46,468 [myid:1] - WARN  [QuorumPeer[myid=1]/0:0:0:0:0:0:0:0:218
31 1:QuorumCnxManager@400] - Cannot open channel to 2 at election address localhost
32 /127.0.0.1:8889

　　這個異常其實能夠忽略，仔細看二、三、3一、32行打印出的信息就明白了。出現這個異常的緣由是由於，如今只啓動了一個zk節點，而在配置文件中卻寫了三個zk的地址，第一個zk節點還沒法與剩下的兩個節點進行通訊，因此只要把三個zk節點都啓動就沒問題了。