在第一次格式化hadoop的时候，可能会出现以下错误信息：

1. 14/08/1007:07:57WARNutil.NativeCodeLoader:Unabletoloadnative-hadooplibraryforyourplatform...usingbuiltin-javaclasseswhereapplicable
2. Stoppingnamenodeson[JavaHotSpot(TM)64-BitServerVMwarning:Youhaveloadedlibrary/home/hadoop/hadoop-2.2.0/lib/native/libhadoop.so.1.0.0whichmighthavedisabledstackguard.TheVMwilltrytofixthestackguardnow.
3. It'shighlyrecommendedthatyoufixthelibrarywith'execstack-c<libfile>',orlinkitwith'-znoexecstack'.
4. cluster1]
5. sed:-eexpression#1,char6:unknownoptionto`s'
6. -c:Unknownciphertype'cd'
7. ^Ccluster1:stoppingnamenode
8. cluster1:stoppingdatanode
9. VM:ssh:CouldnotresolvehostnameVM:Nameorservicenotknown
10. stack:ssh:Couldnotresolvehostnamestack:Nameorservicenotknown
11. warning::ssh:Couldnotresolvehostnamewarning::Nameorservicenotknown
12. will:ssh:Couldnotresolvehostnamewill:Nameorservicenotknown
13. which:ssh:Couldnotresolvehostnamewhich:Nameorservicenotknown
14. fix:ssh:Couldnotresolvehostnamefix:Nameorservicenotknown
15. disabled:ssh:Couldnotresolvehostnamedisabled:Nameorservicenotknown
16. have:ssh:Couldnotresolvehostnamehave:Nameorservicenotknown
17. 64-Bit:ssh:Couldnotresolvehostname64-Bit:Nameorservicenotknown
18. guard:ssh:Couldnotresolvehostnameguard:Nameorservicenotknown
19. HotSpot(TM):ssh:CouldnotresolvehostnameHotSpot(TM):Nameorservicenotknown
20. Java:ssh:CouldnotresolvehostnameJava:Nameorservicenotknown
21. VM:ssh:CouldnotresolvehostnameVM:Nameorservicenotknown
22. stack:ssh:Couldnotresolvehostnamestack:Nameorservicenotknown
23. The:ssh:CouldnotresolvehostnameThe:Nameorservicenotknown
24. recommended:ssh:Couldnotresolvehostnamerecommended:Nameorservicenotknown
25. have:ssh:Couldnotresolvehostnamehave:Nameorservicenotknown
26. guard.:ssh:Couldnotresolvehostnameguard.:Nameorservicenotknown
27. Server:ssh:CouldnotresolvehostnameServer:Nameorservicenotknown
28. loaded:ssh:Couldnotresolvehostnameloaded:Nameorservicenotknown
29. It's:ssh:CouldnotresolvehostnameIt's:Nameorservicenotknown
30. try:ssh:Couldnotresolvehostnametry:Nameorservicenotknown
31. the:ssh:Couldnotresolvehostnamethe:Nameorservicenotknown
32. You:ssh:CouldnotresolvehostnameYou:Nameorservicenotknown
33. that:ssh:Couldnotresolvehostnamethat:Nameorservicenotknown
34. might:ssh:Couldnotresolvehostnamemight:Nameorservicenotknown
35. you:ssh:Couldnotresolvehostnameyou:Nameorservicenotknown
36. library:ssh:Couldnotresolvehostnamelibrary:Nameorservicenotknown
37. fix:ssh:Couldnotresolvehostnamefix:Nameorservicenotknown
38. to:ssh:Couldnotresolvehostnameto:Nameorservicenotknown
39. highly:ssh:Couldnotresolvehostnamehighly:Nameorservicenotknown
40. library:ssh:Couldnotresolvehostnamelibrary:Nameorservicenotknown
41. the:ssh:Couldnotresolvehostnamethe:Nameorservicenotknown
42. 'execstack:ssh:Couldnotresolvehostname'execstack:Nameorservicenotknown
43. '-z:ssh:Couldnotresolvehostname'-z:Nameorservicenotknown
44. now.:ssh:Couldnotresolvehostnamenow.:Nameorservicenotknown
    

以上错误可以在/etc/profile加入以下配置

export HADOOP_HOME=/usr/local/hadoop
export HADOOP_COMMON_LIB_NATIVE_DIR=$HADOOP_HOME/lib/native
export HADOOP_OPTS="-Djava.library.path=$HADOOP_HOME/lib"

然后重新格式化，这时将不会提示错误信息，但是还是有警告信息。

4/08/1007:07:57WARNutil.NativeCodeLoader:Unabletoloadnative-hadooplibraryforyourplatform...usingbuiltin-javaclasseswhereapplicable

为了能彻底解决这些问题，我们还需要在/etc/profile文件中添加以下环境变量

export JAVA_LIBRARY_PATH=$HADOOP_HOME/lib/native

加入了该环境变量，此时如果主机的位数和hadoop库文件的位数不一致也会出现以上的错误。

可以通过uname -a 查看当前系统的信息。

Linux yitian1 2.6.32-573.8.1.el6.x86_64 #1 SMP Tue Nov 10 18:01:38 UTC 2015 x86_64 x86_64 x86_64 GNU/Linux

从以上信息可知，当前系统的linux内核是2.6.32-573.8.1.el6.x86_64，位数是64位

还有通过以下命令查看当前hadoop的库文件是多少位的

file /usr/local/hadoop/lib/native/*

/usr/local/hadoop/lib/native/libhadoop.a: current ar archive
/usr/local/hadoop/lib/native/libhadooppipes.a: current ar archive
/usr/local/hadoop/lib/native/libhadoop.so: ELF 64-bit LSB shared object, x86-64, version 1 (SYSV), dynamically linked, not stripped
/usr/local/hadoop/lib/native/libhadoop.so.1.0.0: ELF 64-bit LSB shared object, x86-64, version 1 (SYSV), dynamically linked, not stripped
/usr/local/hadoop/lib/native/libhadooputils.a: current ar archive
/usr/local/hadoop/lib/native/libhdfs.a: current ar archive
/usr/local/hadoop/lib/native/libhdfs.so: ELF 64-bit LSB shared object, x86-64, version 1 (SYSV), dynamically linked, not stripped
/usr/local/hadoop/lib/native/libhdfs.so.0.0.0: ELF 64-bit LSB shared object, x86-64, version 1 (SYSV), dynamically linked, not stripped

从以上输出信息可以看出，hadoop的版本也是64位的，如果hadoop的版本和系统的版本不一致，则必须要保证他们一致，不一致的情况下，一般是更换hadoop的核心库

注意：记得修改了/etc/profile文件之后，为了让配置立即生效，执行source /etc/profile命令