Build Hadoop pseudo-distributed environment based on CentOS6.5

Recently, has been learning about Hadoop, if you want to learn a language, then the language of the environment is very important to build, just started to try, not successful, and then do not want to try, the back or try to succeed, can be seen in fact some things are not so difficult, just see you have no heart to learn such things.

I have been learning about the environment of Hadoop is based on the article to force star Bo, very good, article link: http://www.powerxing.com/, which we can comb a few of my problems in the building

Problem one: When I hit the wrong environment, or the name and data generated in the ID is not the same, at this time I can directly in the execution./bin/hdfs Namenode-format.

Answer: No, because at this time you have generated a TMP folder under the environment of Hadoop, if you want to reformat, you can first stop-all.sh the command, in the re./bin/hdfs Namenode-format

Question two: When I'm done./sbin/start-dfs.sh and./sbin/start-yarn.sh These two commands, if we can be in the Linux command underground can be used for hdfs additions and deletions, then why we enter in the browser: IP ( or hostname): 50070, the browser cannot find the interface version of the Hadoop file system, you should turn off the firewall at this time:

1.service iptables Stop Stop Firewall

2.chkconfig iptables off

3.chkconfig iptables--list View status

Upload and download features for Hadoop:

./bin/hdfs-ls the directory on the HDFs , such as can be written./bin/hdfs-ls/(View the file under the directory in HDFs) or./bin/hdfs-ls/user (view a list of files in the/user directory)

. /bin/hdfs Dfs-get/output (/output at this time is the file under the HDFs/directory)/tmp/name1234 (native directory)

Explanation: The file of/output above HDFs is copied to the/tmp/name1234 of this machine, at this time the directory is called/tmp/name1234 this file

./bin/hdfs dfs-put./etc/hadoop/*.xml (local directory, current directory./etc/hadoop/directory below all files ending in. xml)/input (HDFs file)

Explanation: Directories under directory./etc/hadoop directory under the directory of all files uploaded with the. xml file ending in HDFs/input