sudoers not honoring hostnames

[oshunluvr]

New Kubuntu 16.04 install, adding features from previous 15.04 install. Added exact copy of /etc/sudoers.d/apt from 15.04 to 16.04 but it does not work as expected. File contents:

myusername myhostname = NOPASSWD: /usr/bin/apt, /usr/bin/apt-get, /usr/bin/add-apt-repository

results in 15.04 in user "myusername" being able to run apt, apt-get, and add-apt-repository from the CLI using sudo without a password prompt. However, same exact syntax in 16.04 results in password prompt.

In the 16.04 install, changing "myhostname" to "ALL" resumes the no password behavior. Both installs have exact same /etc/hosts files, running on bare metal on the same system, and the "hostname" command results in the same reply with the correct hostname. I have compared the subject files several times and there are no differences. No errors editing any of the files using visudo. Permissions and syntax same on both systems.

This leads me to conclude sudoers is not honoring the hostname in the sudoers file(s).

[oshunluvr (stuartksmith)]

New info: Using the FQDN instead of the shortened hostname version works. As before, in 15.04 shortened hostname works in sudoers.d/ files but in 16.04 it does not.

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.

[oshunluvr (stuartksmith)]

Now using 18.04 KDEneon and last month sometime an update broke this functionality even further. The FQDN and indeed no other format works any longer.