I've just installed Xubuntu 18.04 (Bionic) and facing this issue, I wanted to report this as a bug on launchpad but thought of confirming it from here first. Thing is that when I add a group to the user like below, it should take effect on the next user login, right?
sudo usermod -aG docker prahlad
This behavior used to work until 16.04 from what I remember, but today I logged out and back in several times, yet when I see my groups by running the
groups command, I'm unable to see docker added to it. However, when I created a new shell, I was able to see the new group:
su prahlad -
And of course, when I rebooted my laptop completely, I was able to able to see the docker group. Can somebody confirm whether this is a new issue introduced in Bionic? Or maybe, it just happens with docker installed?