Mapreduce job stuck at map 0% reduce 0%. : Could not resolve hostname
Mapreduce jobs are not running. And the below error message is coming when starting HDFS daemons.
These above error messages are received when there is some issue with ssh communication. So, in these situations, we need to remove openssh-client and openssh-server and re-install them again.
Once the ssh is re-installed, we will not get Could not resolve hostname error message while starting hadoop daemons. And ssh communication will not be any more problem, so mapreduce job will start running smoothly.