linux – How does google cloud setup sudoers for googlecloudshell user without adding it to the /etc/group file

I am not a new user on unix and linux. Before today I know everything works needs a logical configuration to make it work.

But today, when I create ubuntu instances on google cloud, I found something unusual.

I create an additional user besides the default cloud shell user which I use browser to login.

the additional user has the correct entry in /etc/group, but the cloud shell user doesn’t. They both are added to sudoers through google-sudoers group.

sudoers configuration:

/etc/sudoers:

”’
root ALL=(ALL:ALL) ALL

%admin ALL=(ALL) ALL

%sudo ALL=(ALL:ALL) ALL

#includedir /etc/sudoers.d
”’

files in /etc/sudoers.d:

”’
root@master:/etc/sudoers.d# ls

90-cloud-init-users README google_sudoers

root@master:/etc/sudoers.d# cat 90-cloud-init-users

ubuntu ALL=(ALL) NOPASSWD:ALL

root@master:/etc/sudoers.d# cat google_sudoers

%google-sudoers ALL=(ALL:ALL) NOPASSWD:ALLroot@master:/etc/sudoers.d#
”’

/etc/group:

”’

sudo:x:27:ubuntu

admin:x:113:

netdev:x:114:ubuntu,scott.lai,scott2020test

_chrony:x:115:

ubuntu:x:1000:scott.lai,scott2020test

google-sudoers:x:1001:scott.lai

scott.lai:x:1002:

scott2020test:x:1003:

”’

NO where to find scott2020test in google-sudoers, so how does scott2020test been included in google-sudoers?

Please notice that ubuntu is in sudoer file as a user, not a group.

Can someone explain?