Error contacting service. It is probably not running.

平台：centos-6.3-i386

　　　jdk-7u51

storm 0.9.1

　　　python 2.6.6

　　   hadoop 1.2.1

运行zookeeperd后显示启动成功：

JMX enabled by default
Using config: /data/programfiles/zookeeper-3.4.5/bin/../conf/zoo.cfg
Starting zookeeper ... STARTED

但用bin/zkServer.sh status查看，反馈如下：

JMX enabled by default
Using config: /data/programfiles/zookeeper-3.4.5/bin/../conf/zoo.cfg
Error contacting service. It is probably not running.

很奇怪，我用netstat -lntup查了一下端口，没发现2181端口被启用

查了zookeeper.out日志，发现如下的错误：

2014-04-16 11:59:54,425 [myid:] - ERROR [main:ZooKeeperServerMain@63] - Unexpected exception, exiting abnormally
java.net.BindException: Address already in use
    at sun.nio.ch.Net.bind0(Native Method)
    at sun.nio.ch.Net.bind(Net.java:344)
    at sun.nio.ch.Net.bind(Net.java:336)
    at sun.nio.ch.ServerSocketChannelImpl.bind(ServerSocketChannelImpl.java:199)
    at sun.nio.ch.ServerSocketAdaptor.bind(ServerSocketAdaptor.java:74)
    at sun.nio.ch.ServerSocketAdaptor.bind(ServerSocketAdaptor.java:67)
    at org.apache.zookeeper.server.NIOServerCnxnFactory.configure(NIOServerCnxnFactory.java:95)
    at org.apache.zookeeper.server.ZooKeeperServerMain.runFromConfig(ZooKeeperServerMain.java:110)
    at org.apache.zookeeper.server.ZooKeeperServerMain.initializeAndRun(ZooKeeperServerMain.java:86)
    at org.apache.zookeeper.server.ZooKeeperServerMain.main(ZooKeeperServerMain.java:52)
    at org.apache.zookeeper.server.quorum.QuorumPeerMain.initializeAndRun(QuorumPeerMain.java:116)
    at org.apache.zookeeper.server.quorum.QuorumPeerMain.main(QuorumPeerMain.java:78)

从错误信息来看，是端口被使用了，但我用netstat -lntup是没被使用的，再用 lsof -i:2181，发现了2181端口果然被占用了

[root@ programfiles]# lsof -i:2181
COMMAND     PID USER   FD   TYPE     DEVICE SIZE/OFF NODE NAME
memcached 15843 root   56u  IPv4 1650939492      0t0  TCP .:11213->.:eforward (ESTABLISHED)
php-cgi   28154  www    7u  IPv4 1650939491      0t0  TCP .:eforward->.:11213 (ESTABLISHED)

接下来就很好办了，启用另外一个端口就ok了