第一天的时候，Zookeeper的安装是成功的，也启动成功，但是第二天不知道就怎么了，突然就一直启动不起来。在‘#’后面的是注释：
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# 目前所在的位置：
[scidb@localhost bin]$ pwd
/home/scidb/zookeeper/zookeeper-3.4.8/bin
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# 在bin的文件下有这些文件：
[scidb@localhost bin]$ ls?
README.txt ? ?zkCli.cmd ?zkEnv.cmd ?zkServer.cmd ?zookeeper.out
zkCleanup.sh ?zkCli.sh ? zkEnv.sh ? zkServer.sh
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# 接下来启动 zkServer.sh
[scidb@localhost bin]$ sudo sh zkServer.sh start
ZooKeeper JMX enabled by default
Using config: /home/scidb/zookeeper/zookeeper-3.4.8/bin/../conf/zoo.cfg
Starting zookeeper ... STARTED
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# 看起来是启动成功了哦，然后我们再来看看是否真的启动成功了。
[scidb@localhost bin]$ sh zkServer.sh status
ZooKeeper JMX enabled by default
Using config: /home/scidb/zookeeper/zookeeper-3.4.8/bin/../conf/zoo.cfg
Error contacting service. It is probably not running.
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# 呵呵，居然没有启动起来。然后我用zkCli.sh 尝试启动客户端，结果。。
[scidb@localhost bin]$ sh zkCli.sh?
Connecting to localhost:2181
2016-02-29 15:50:04,735 [myid:] - INFO ?[main:Environment@100] - Client environment:zookeeper.version=3.4.8--1, built on 02/06/2016 03:18 GMT
2016-02-29 15:50:04,739 [myid:] - INFO ?[main:Environment@100] - Client environment:host.name=localhost
2016-02-29 15:50:04,739 [myid:] - INFO ?[main:Environment@100] - Client environment:java.version=1.8.0_25
2016-02-29 15:50:04,740 [myid:] - INFO ?[main:Environment@100] - Client environment:java.vendor=Oracle Corporation
2016-02-29 15:50:04,741 [myid:] - INFO ?[main:Environment@100] - Client environment:java.home=/usr/java/jdk1.8.0_25/jre
2016-02-29 15:50:04,741 [myid:] - INFO ?[main:Environment@100] - Client environment:java.class.path=/home/scidb/zookeeper/zookeeper-3.4.8/bin/../build/classes:/home/scidb/zookeeper/zookeeper-3.4.8/bin/../build/lib/*.jar:/home/scidb/zookeeper/zookeeper-3.4.8/bin/../lib/slf4j-log4j12-1.6.1.jar:/home/scidb/zookeeper/zookeeper-3.4.8/bin/../lib/slf4j-api-1.6.1.jar:/home/scidb/zookeeper/zookeeper-3.4.8/bin/../lib/netty-3.7.0.Final.jar:/home/scidb/zookeeper/zookeeper-3.4.8/bin/../lib/log4j-1.2.16.jar:/home/scidb/zookeeper/zookeeper-3.4.8/bin/../lib/jline-0.9.94.jar:/home/scidb/zookeeper/zookeeper-3.4.8/bin/../zookeeper-3.4.8.jar:/home/scidb/zookeeper/zookeeper-3.4.8/bin/../src/java/lib/*.jar:/home/scidb/zookeeper/zookeeper-3.4.8/bin/../conf:.:/usr/java/jdk1.8.0_25/lib/jt.jar:/usr/java/jdk1.8.0_25/lib/tools.jar:%JRE_HOME/lib:/home/123/Desktop/123/scidb4j.jar:/home/123/Desktop/123/protobuf-java.jar
2016-02-29 15:50:04,741 [myid:] - INFO ?[main:Environment@100] - Client environment:java.library.path=:/opt/scidb/14.12/lib:/opt/scidb/14.12/lib:/opt/scidb/14.12/lib:/usr/java/packages/lib/amd64:/usr/lib64:/lib64:/lib:/usr/lib
2016-02-29 15:50:04,741 [myid:] - INFO ?[main:Environment@100] - Client environment:java.io.tmpdir=/tmp
2016-02-29 15:50:04,741 [myid:] - INFO ?[main:Environment@100] - Client environment:java.compiler=<NA>
2016-02-29 15:50:04,741 [myid:] - INFO ?[main:Environment@100] - Client environment:os.name=Linux
2016-02-29 15:50:04,741 [myid:] - INFO ?[main:Environment@100] - Client environment:os.arch=amd64
2016-02-29 15:50:04,741 [myid:] - INFO ?[main:Environment@100] - Client environment:os.version=2.6.32-431.29.2.el6.x86_64
2016-02-29 15:50:04,741 [myid:] - INFO ?[main:Environment@100] - Client environment:user.name=scidb
2016-02-29 15:50:04,741 [myid:] - INFO ?[main:Environment@100] - Client environment:user.home=/home/scidb
2016-02-29 15:50:04,742 [myid:] - INFO ?[main:Environment@100] - Client environment:user.dir=/home/scidb/zookeeper/zookeeper-3.4.8/bin
2016-02-29 15:50:04,743 [myid:] - INFO ?[main:ZooKeeper@438] - Initiating client connection, connectString=localhost:2181 sessionTimeout=30000 watcher=org.apache.zookeeper.ZooKeeperMain$MyWatcher@277050dc
Welcome to ZooKeeper!
2016-02-29 15:50:04,768 [myid:] - INFO ?[main-SendThread(localhost:2181):ClientCnxn$SendThread@1032] - Opening socket connection to server localhost/127.0.0.1:2181. Will not attempt to authenticate using SASL (unknown error)
JLine support is enabled
[zk: localhost:2181(CONNECTING) 0] 2016-02-29 15:50:04,828 [myid:] - WARN ?[main-SendThread(localhost:2181):ClientCnxn$SendThread@1162] - Session 0x0 for server null, unexpected error, closing socket connection and attempting reconnect
java.net.ConnectException: Connection refused
at sun.nio.ch.SocketChannelImpl.checkConnect(Native Method)
at sun.nio.ch.SocketChannelImpl.finishConnect(SocketChannelImpl.java:716)
at org.apache.zookeeper.ClientCnxnSocketNIO.doTransport(ClientCnxnSocketNIO.java:361)
at org.apache.zookeeper.ClientCnxn$SendThread.run(ClientCnxn.java:1141)
2016-02-29 15:50:04,935 [myid:] - INFO ?[main-SendThread(localhost:2181):ClientCnxn$SendThread@1032] - Opening socket connection to server localhost/0:0:0:0:0:0:0:1:2181. Will not attempt to authenticate using SASL (unknown error)
2016-02-29 15:50:04,937 [myid:] - WARN ?[main-SendThread(localhost:2181):ClientCnxn$SendThread@1162] - Session 0x0 for server null, unexpected error, closing socket connection and attempting reconnect
java.net.ConnectException: Connection refused
at sun.nio.ch.SocketChannelImpl.checkConnect(Native Method)
at sun.nio.ch.SocketChannelImpl.finishConnect(SocketChannelImpl.java:716)
at org.apache.zookeeper.ClientCnxnSocketNIO.doTransport(ClientCnxnSocketNIO.java:361)
at org.apache.zookeeper.ClientCnxn$SendThread.run(ClientCnxn.java:1141)
2016-02-29 15:50:05,039 [myid:] - INFO ?[main-SendThread(localhost:2181):ClientCnxn$SendThread@1032] - Opening socket connection to server localhost/192.168.133.130:2181. Will not attempt to authenticate using SASL (unknown error)
2016-02-29 15:50:05,040 [myid:] - WARN ?[main-SendThread(localhost:2181):ClientCnxn$SendThread@1162] - Session 0x0 for server null, unexpected error, closing socket connection and attempting reconnect
java.net.ConnectException: Connection refused
at sun.nio.ch.SocketChannelImpl.checkConnect(Native Method)
at sun.nio.ch.SocketChannelImpl.finishConnect(SocketChannelImpl.java:716)
at org.apache.zookeeper.ClientCnxnSocketNIO.doTransport(ClientCnxnSocketNIO.java:361)
at org.apache.zookeeper.ClientCnxn$SendThread.run(ClientCnxn.java:1141)
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# 坑爹啊， 第一天的时候明明好好的，怎么现在就成这样的了。。。
# 我检查了配置文件，conf/zoo.cfg
[scidb@localhost bin]$ cat ../conf/zoo.cfg?
tickTime=2000
initLimit=5
syncLimit=2
dataDir=/var/lib/zookeeper/
clientPort=2181
server.1=localhost:2888:3888
# 好好的，没什么问题啊。于是我又检查了 /var/lib/zookeeper/myid
[scidb@localhost bin]$ cat /var/lib/zookeeper/myid?
1
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# 乍一看配置没错啊，我想看看到底2181端口是否被占用。
[scidb@localhost bin]$ sudo netstat -anp | grep 2181
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# 呵呵居然什么都没有，我启动了tomcat，然后用命令在看看
[scidb@localhost bin]$ sudo netstat -anp | grep 8080
tcp ? ? ? ?0 ? ? ?0 :::8080 ? ? ? ? ? ? ? ? ? ? :::* ? ? ? ? ? ? ? ? ? ? ? ?LISTEN ? ? ?5027/java?
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# 命令没有问题，程序是真的没有启动起来。
# 接下来我在google和百度里看了搜索了许多有关于这个错误的信息。
分别搜索了‘at org.apache.zookeeper.ClientCnxn$SendThread.run(ClientCnxn.java:1141)’、
‘at org.apache.zookeeper.ClientCnxnSocketNIO.doTransport(ClientCnxnSocketNIO.java:361)
’、‘INFO ?[main-SendThread(localhost:2181):ClientCnxn$SendThread@1032] - Opening socket connection to server localhost/0:0:0:0:0:0:0:1:2181. Will not attempt to authenticate using SASL (unknown error)’……
看了很多在http://stackoverflow.com/ 上的回答。。。
我靠，居然都没有用啊，多数都在强调你的配置文件的问题。但是配置都已经看烂了，没有什么问题啊！！！
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# 好吧，最后我快绝望的我切换成root用户，然后象征性的启动，然后查看状态。
[root@localhost bin]# sh zkServer.sh start
ZooKeeper JMX enabled by default
Using config: /home/scidb/zookeeper/zookeeper-3.4.8/bin/../conf/zoo.cfg
Starting zookeeper ... STARTED
[root@localhost bin]# sh zkServer.sh status
ZooKeeper JMX enabled by default
Using config: /home/scidb/zookeeper/zookeeper-3.4.8/bin/../conf/zoo.cfg
Mode: standalone
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# 妈的，你敢信。。。居然好了。。。
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# 然后查看端口占用
[scidb@localhost bin]$ sudo netstat -anp | grep 2181
tcp ? ? ? ?0 ? ? ?0 :::2181 ? ? ? ? ? ? ? ? ? ? :::* ? ? ? ? ? ? ? ? ? ? ? ?LISTEN ? ? ?5635/java?
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原文：http://rayfuxk.iteye.com/blog/2279596