sudo inside docker (on fedora) ask for password, on host it doesn't ask password

Question

I am testing something in docker, it requires sudo without entering password, I added required entries in /etc/sudoers. After that in host it doesn't ask for password. But in case of docker it still ask for password. BTW, I am running fedora 24 in VirtualBox VM on a Fedora 24 host.

Here is the details...

abc@webster $ sudo bash

root@webster $ cat /etc/sudoers
## Sudoers allows particular users to run various commands as
...
...
## Allow root to run any commands anywhere 
root    ALL=(ALL)       ALL

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

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

%users ALL=(ALL) ALL
%admin ALL=(ALL) NOPASSWD: ALL

%sudo   ALL=(ALL:ALL)   ALL
abc      ALL=(ALL) NOPASSWD: ALL
#abc      ALL=(ALL)       ALL


abc@webster $ id
uid=1000(abc) gid=1000(abc) groups=1000(abc),10(wheel),100(users),977(docker),1001(admin) context=unconfined_u:unconfined_r:unconfined_t:s0-s0:c0.c1023


abc@fc-docker $ sudo bash
[sudo] password for abc: 

Answer 1

Adding this as an answer for more clarity. Docker instance had its own /etc/sudoers. Which need to be updated to allow sudo without password. Login to docker instance as " docker exec -it fc-docker bash ", you will be logged in as root. Then add "abc ALL=(ALL) NOPASSWD: ALL" to /etc/sudoers/. Logout & login back, we can do sudo without password.

Answer 2

Here's how I setup a non-root user with passworsdless access to the sudo group using the base image of ubuntu:18.04:

RUN \
    groupadd -g 999 foo && useradd -u 999 -g foo -G sudo -m -s /bin/bash foo && \
    sed -i /etc/sudoers -re 's/^%sudo.*/%sudo ALL=(ALL:ALL) NOPASSWD: ALL/g' && \
    sed -i /etc/sudoers -re 's/^root.*/root ALL=(ALL:ALL) NOPASSWD: ALL/g' && \
    sed -i /etc/sudoers -re 's/^#includedir.*/## **Removed the include directive** ##"/g' && \
    echo "foo ALL=(ALL) NOPASSWD: ALL" >> /etc/sudoers && \
    echo "Customized the sudoers file for passwordless access to the foo user!" && \
    echo "foo user:";  su - foo -c id

What happens with the above code:

• The user and group foo is created.
• The user foo is added to the both the foo and sudo group.
• The uid and gid is set to the value of 999.
• The home directory is set to /home/foo.
• The shell is set to /bin/bash.
• The sed command does inline updates to the /etc/sudoers file to allow foo and root users passwordless access to the sudo group.
• The sed command disables the #includedir directive that would allow any files in subdirectories to override these inline updates.