Centos 7 - adding a user to sudoers group - still is not in the sudoers file - why?

Question

[user@localhost ~]$ su -
Password: 
Last login: ...
[root@localhost ~]# usermod -aG wheel user
[root@localhost ~]# exit
logout
[user@localhost ~]$ sudo echo 123
[sudo] password for user: 
user is not in the sudoers file.  This incident will be reported.

What do I do wrong?

Solution 1

My experience is that 'user' needs to log out and in again. Try the 'id' command to see if the system thinks that 'user' is in the wheel group or not.

Solution 2

In stock CentOS 7, wheel is not enabled in the default /etc/sudoers file.

## Allows people in group wheel to run all commands
# %wheel        ALL=(ALL)       ALL

## Same thing without a password
# %wheel        ALL=(ALL)       NOPASSWD: ALL

Did you uncomment those lines?

Comments

[Jenny D]

Possible duplicate of Adding secondary groups and running processes

[Syeda]

Linux (and most posix systems) only load your group memberships during login. You'll have to log out and log back in for the system to pick up the change and your user account to be able to run sudo.

[reinierpost]

Or you can start a new shell with newgrp wheel.

[Why]

%wheel ALL=(ALL) ALL is apparently uncommented by default

[Andrew Schulman]

Please don't post screenshots of text. Inlcude the text in your answer instead, so it's readable by screen readers and search engines.