参考错误列表
http://www.geedoo.info/category/hadoop%E8%BF%90%E7%BB%B4
1.在手动执行bin/hdfs secondarynamenode -checkpoint force手动执行checkpoint检查时出现错误
14/12/20 15:17:43 INFO common.Storage: Cannot lock storage /usr/local/hadoop/dfs/checkpoint. The directory is already locked
14/12/20 15:17:43 FATAL namenode.SecondaryNameNode: Failed to start secondary namenode
java.io.IOException: Cannot lock storage /usr/local/hadoop/dfs/checkpoint. The directory is already locked
这是因为Secondarynamenode进程正在使用，不能在运行子进程了，需kill -9 pid，在执行
2.配置zookeeper时，
java.net.NoRouteToHostException: 没有到主机的路由 --不仅这个有错误，其他主机间的操作，都提示这个
十有八九是某台主机的防火墙限制，最好的办法就是关闭防火墙，实际中不能这么直接，需添加端口信任
注意：需要在 root 用户下检查 防火墙状态，我在普通用户下检查，什么都没显示，还以为是已经关闭了
（1） 重启后永久性生效：
开启：chkconfig iptables on
关闭：chkconfig iptables off
（2） 即时生效，重启后失效：
开启：service iptables start
关闭：service iptables stop
3.启动HDFS时报如下错误
have: ssh: Could not resolve hostname have: Name or service not known
loaded: ssh: Could not resolve hostname loaded: Name or service not known
VM: ssh: Could not resolve hostname VM: Name or service not known
library: ssh: Could not resolve hostname library: Name or service not known
which: ssh: Could not resolve hostname which: Name or service not known
You: ssh: Could not resolve hostname You: Name or service not known
stack: ssh: Could not resolve hostname stack: Name or service not known
might: ssh: Could not resolve hostname might: Name or service not known
have: ssh: Could not resolve hostname have: Name or service not known
guard.: ssh: Could not resolve hostname guard.: Name or service not known
Java: ssh: Could not resolve hostname Java: Name or service not known
disabled: ssh: Could not resolve hostname disabled: Name or service not known
The: ssh: Could not resolve hostname The: Name or service not known
will: ssh: Could not resolve hostname will: Name or service not known
VM: ssh: Could not resolve hostname VM: Name or service not known
try: ssh: Could not resolve hostname try: Name or service not known
the: ssh: Could not resolve hostname the: Name or service not known
fix: ssh: Could not resolve hostname fix: Name or service not known
stack: ssh: Could not resolve hostname stack: Name or service not known
Server: ssh: Could not resolve hostname Server: Name or service not known
guard: ssh: Could not resolve hostname guard: Name or service not known
to: ssh: Could not resolve hostname to: Name or service not known
64-Bit: ssh: Could not resolve hostname 64-Bit: Name or service not known
you: ssh: Could not resolve hostname you: Name or service not known
highly: ssh: Could not resolve hostname highly: Name or service not known
输出native环境变量
export HADOOP_COMMON_LIB_NATIVE_DIR=/app/cloud/hadoop/hadoop-2.4.0/lib/native
