How to untangle the systemd-resolved DNS mess
The change from the venerable nsswitch and NetworkManager to systemd-resolved has damaged and slowed name services. The result of this resolver change was apparent in a number of symptoms. Inability to find the addresses of most remote servers resulting in timeouts was the most noticeable. When the connections were made, They were very slow to respond. I didn’t really understand how much slower until after I fixed the problem.
systemd — #12: Fixing systemd-resolved name service failures using Ansible
Name resolution and the ever-changing networking landscape.