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FQDN is not set for hosts.. Any issues in prod environment



I have few servers in prod environment and I came to know that the hosts are not having FQDN during verification of the setup.

Is FQDN mandatory? If FQDN is not set then what kind of issues do we see in future?

Please let me know.

Note: hostname -f gives me only the hostname but not FQDN.

Thanks for your time.




FQDN is required if you are not using DNS/reverse DNS.


You can manage this by maintaining /etc/hosts but whenever IP changes in the environment then you have to update the entries in the host file.

FQDN is recommended for reasons like users does not need to have local /etc/hosts in their env to reach the cluster.

Hope that helps


Dear @Geoffrey Shelton Okot

Many thanks for your kind response.

We are using DNS here and I would like to know if any Hadoop service is impacted if FQDN is not used.

Also, will it be a problem in any job execution or any where while using Hadoop?

Note: Everything is good with respect to DNS look up and I am worried whether hadoop usage will be impacted or not.



If you are using DNS then that should be fine as the hostname resolution will be automatically done.

Have you encountered any issues ? Here is the check DNS document


@Geoffrey Shelton Okot

No issues as of now.. but this is going to live and I am worried if there would be any issue in future?

To ask in one line:

What happens if the host does not have FQDN? Any technical issues in Hadoop environment other than DNS issues?


Can anyone please respond.



Extract for the Hortonworks documentation

"All hosts in your system must be configured for DNS and Reverse DNS."

If you are unable to configure DNS and Reverse DNS, you must edit the hosts' file on every host in your cluster to contain the address of each of your hosts and to set the Fully Qualified Domain Name hostname of each of those hosts.

So that clearly answers your worries 🙂




Thanks for your time and I believe there would be no issues other than DNS issues.

Thanks again.



You won't have DNS issues and please don't hesitate if you encounter ay problem. We have a great forum and very savvy members.

If you found this answer addressed your question, please take a moment to log in and click the "Accept" link on the answer.



Has your problem been resolved please revert

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