Create admin user
1. Create user:
VAR_USERNAME=<username>
useradd -m -s /bin/bash -G sudo ${VAR_USERNAME} && pveum user add ${VAR_USERNAME}@pam
2. Create the group:
pveum group add admin -comment "System Administrators"
pveum acl modify / -group admin -role Administrator
3. Assign group to user:
pveum user modify <user>@pam -group admin
3+1. Disable root on gui (optional):
pveum user modify root@pam --enable 0
There are usecases when you need it, to enable
pveum user modify root@pam --enable 1