DNS Issue on vcsa upgrade from 5.5 to 6

[RYVN]

We are in the process of upgrading our vCenter (vcsa) from 5.5 to 6.0 U2. During the upgrade I get a warning that the "Host name xxxx is not DNS resolvable, but matches the VC and SSO certificates. If you do not configure valid DNS resolvable hostname mapping, then you might not be able to connect to vCSA 6.0 afterwards. Please either update appliance /etc/hosts file to properly access DNS servers or update appliance DNS servers with the proper host name mapping. To check if DNS has record about local host name, please execute `dig xxxx +short` locally on the appliance, or `nslookup xxxx` on a windows machine". However, I have verified through nslookup on the appliance that the hostname does resolve. I have also checked that DNS is correct on the appliance and our DNS entries are correct. Since the hostname does resolve, I would imagine I could get the vcsa after the upgrade just fine. Any thoughts are much appreciated. Thanks!

[Camero]

Kindly make sure the reverse nslookup of the IP resolves the FQDN of the vCenter server Hoostname.

[RYVN · Accepted solution]

Thanks Camero. We double-checked and ensured everything resolved correctly. The error still persisted, but we felt confident we could move forward. The vcsa upgraded fine and we could access/resolve afterward.

[Camero]

Just make sure after upgrade all the users are able to access various features and all of the management clients are working.

Regarding the warning message, the message was put in place to notify the Admins about the underlying Network inconsistency. You may very well ignore this issue if your current environment is simple but again this may become important if your environment has a scaled out architecture.