Changing hostname of vCenter server fails with error "Unable to set hostname"

Products

• VMware vCenter Server

Issue/Introduction

• Changing the hostname of the vCenter server using /opt/vmware/share/vami/vami_config_net fails with the error "Unable to set hostname to <new_hostname> reverting to previous hostname:"
• The hostname is being changed from one case to another, or the short name to full FQDN

Environment

• VMware vCenter Server 6.5.x
• VMware vCenter Server 6.7.x
• vCenter 7.x
• vCenter 8.x

Cause

This issue occurs when the existing hostname of the vCenter is hard coded in the /etc/hosts file.

Example:

$ cat /etc/hosts

# Begin /etc/hosts
192.168.1.15 vc.example.com
# End /etc/hosts

Resolution

1. Edit /etc/hosts and remove the vCenter entry
2. Clear DNS cache on the vCenter Appliance:
   $ systemctl restart dnsmasq
$ systemctl restart systemd-resolved
   
   
3. Validate if your DNS servers are able to resolve the vCenter's fully qualified domain name:
   $ nslookup <vCenter_FQDN>
$ nslookup <vCenter_IP>

Note: Do not update or remove anything between the #VAMI_EDIT_BEGIN and #VAMI_EDIT_END sections.

Additional Information

Having an entry for the vCenter FQDN in /etc/hosts is not a requirement if external DNS is able to resolve the vCenter FQDN.