Linux group membership problem for VNC session

Question

In an almalinux9.5 machine, I am sudo user. I am using a vnc session to access the machine. I've added myself from this vnc machine to linux groups using :

sudo usermod -aG <group-name> <user-name>

However when checking my groups, I am not able to see the new groups added except in two cases:

Logging again from my existing terminal : su -l $USER . Opening a new ssh session. Note that: In the vnc session, when opening another terminal, and checking the groups, I can't see the new groups added, expect "as mentioned above" by re-logging. So as workaround I need to re-login everytime I open a new terminal or work from ssh which is not practical in my case.

Do I miss something?

Answer 1

The process group membership is assigned at login time and a few other times (like su, sudo) and existing processes (like your vnc session) do not get the new groups.

If you close your vnc session and start a new one, the issue will go away, the new session will have the group memberships that existed at its start.

There are exactly two solutions to this:

• Do what you are doing, elevate to the new groups each time you need them.
• Restart your session so the the new permissions can propagate to the new processes.

Answer 2

Solved by killing all the user processes:

sudo pkill -9 -u $USER

In my case, vnc will be restarted automatically as I am having in the service file:

[Service]
Restart=on-success
RestartSec=10

However, restarting vnc only did not solve the issue.