Error when starting Hadoop: Localhost:ssh:Could not resolve hostname localhost:temporary failure in name resolution "

This error is because the configuration file is not configured properly. The solution is as follows:

1 Open Profile File

Vim/etc/profile

2 The content that is added at the end of the document should be as follows (two highlighted sentences are generally missing):

Export JAVA_HOME=/USR/JAVA/JDK

Export hadoop_home=/itcast/hadoop-2.6.4

Export hadoop_common_lib_native_dir= $HADOOP _home/lib/native
Export hadoop_opts= "-djava.library.path= $HADOOP _home/lib"

Export path= $PATH: $JAVA _home/bin: $HADOOP _home/bin

3 re-execute the file

Source/etc/profile

At this point, the problem is resolved.

Error when starting Hadoop: Localhost:ssh:Could not resolve hostname localhost:temporary failure in name resolution "