allowing a non-root user to restart a service on Ubuntu Linux server

As described by ChatGPT, the preferred method was to create sudoers rules for the relevant service(s).

sudo visudo -f /etc/sudoers.d/ourapi

and inside that file, write

deployuser ALL=NOPASSWD: usr/bin/systemctl restart ourapi.service, \

                         usr/bin/systemctl start ourapi.service, \

                         usr/bin/systemctl stop ourapi.service, \

                         usr/bin/systemctl status ourapi.service

where ourapi.service is the service and deployuser is the non-root user.

Here, we double-checked the location of systemctl using 

which systemctl

After doing this, on logging on as deployuser, we can do things like

sudo systemctl start ourapi.service

where it will prompt for deployuser's password and then carry out the command.

But a caveat - we need to type exactly the same command as mentioned in the custom sudoers file - even equivalent commands like

sudo systemctl start ourapi

will not work unless we add that to the sudoers file also.