Hi,
Please first check all the configuration files in pseudo-distributed and namenode in case of hadoop cluster.
Then check whether any ip is updated or not due to the reboot or shutdown.
Then check whether password free ssh connection is successfully working or not by using following command - ssh
It is didn't ask for password that mean password free ssh connection is working fine.

If you find any error in above process. Please update the setting, stop all the services and start again.
Hope this helps.
Thanks.

hi Anusha,

Are you executing hadoop in Pseudo mode --> Cloudera VM or did you install hadoop manually . If it is pseudo mode, all daemons will be executed on one host by default.