OK, I've found the problem. Strange side observation: My power cable was loose, and when pulling the network cable to ensure there's no DHCP response, I accidently pulled the power cable as well, thus forcing the machine into a hard immediate shutdown.
After booting from that hard shutdown, the machine had the new hostname, but after booting again, the machine came up with it's old hostname. reason: The ubuntu server installation image (which I used to install that machine) contains cloud-init. There's several configuration files in /var/lib/cloud/instance, e.g. user-data.txt cloud-config.txt obj.pkl. Some of them fresh, obviously modified or recreated today. Removing them solves the problem. So the reason of the problem is: Although it's not a cloud machine, but a physical machine, ubuntu installs that cloud stuff. That cloud stuff should configure the machine exactly once, but keeps reconfiguring the machine at every boot time, resetting the machine to those settings entered at installation time. which probably means, and that's a security problem, that it resets the admins user account and password to the settings at installation time. If the admin changes the password (e.g. because compromised), it would probably happen that the machine resets to the old password in the same way it sets the old hostname. -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1780867 Title: hostname unchangeable / some daemon changes and resets /etc/hostname To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+bug/1780867/+subscriptions -- ubuntu-bugs mailing list [email protected] https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
