I am running Ubuntu 18.04 in a VM. When I check the hostname using hostname or the fully qualified domain name using hostname -f, hostname --fqdn or hostnamectl I get the default ubuntu for each. I want to permanently update the hostname to host and the fully qualified domain name to host.okd.dns.
I have changed the file /etc/hostname to include only the name host. I have also changed the file /etc/hosts to appear as follows (excluding IPv6 hosts):
127.0.0.1 localhost
127.0.1.1 host.okd.dns
After saving and rebooting the VM, when I check hostname it returns host as expected, but when I check the FQDN using hostname -f, hostname --fqdn or hostnamectl it also returns host only without the .okd.dns appended to it as I would expect.
There seem to be several methods of updating the FQDN for Ubuntu 18.04 and I have tried most of them, including this method, which seems to be the most common. What do I need to do to get the changes to the FQDN to update and stick?
Apparently, I needed to add host after host.okd.dns in the /etc/hosts file. I was sure I had tried this in the past, but perhaps there was some other error I had made somewhere and this wasn't reflected. Once doing this and after a reboot, hostname -f and hostname --fqdn both return host.okd.dns as expected.