Hadoop mapreduce has “Cannot resolve the host name” error

问题

Now I run Hadoop mapreduce job, the input data comes from HBase table, recently there is an error, the error is below:

ERROR mapreduce.TableInputFormatBase: Cannot resolve the host name for /172.16.4.195 because of javax.naming.NameNotFoundException: DNS name not found [response code 3]; remaining name '195.4.16.172.in-addr.arpa'

*172.16.4.195*is cluster node(slave)ip adress, I do not know what is "195.4.16.172".

There was no such error when I firstly run this job,I do not know why there is such an error. If you solved the problem,please tell me,thank you.

回答1:

reverse dns not found, you need add something like

172.16.4.195 master_host_name

to hosts file

if running on linux, the file located at /etc/hosts

if running on windows, the file located at %WINDIR%/System32/Drivers/etc/hosts

来源：https://stackoverflow.com/questions/12086954/hadoop-mapreduce-has-cannot-resolve-the-host-name-error