Start Service with Sudo

Question

I am trying to run an Express API server with sudo permissions and have it automatically start on boot.

The API needs access to bcm2835 library, and I get the following when trying to run node server.js

bcm2835_init: Unable to open /dev/mem: Permission denied /home/pi/Documents/node_modules/rpio/lib/rpio.js:104
return bindfunc(optarg);

Error: Could not initialize bcm2835 library
at bindcall (/home/pi/...) etc.

However it boots up fine running sudo node server.js.

I have created a service file at /etc/systemd/system as follows:

[Unit]
Description=Node API
After=network.target

[Service]
ExecStart=/usr/bin/node /home/pi/Documents/server.js
Restart=always
SyslogIdentifier=controller
User=root
Group=root
Environment=

TimeoutStopSec=30

[Install]
WantedBy=multi-user.target

I found some guidance here and here, but they seem slightly off, since a sub-command needs sudo/root privileges.

When running service controller start from the command line it prompts for a username and password.

How can I run this service with proper permissions so it boots up with the Pi?

Solution

you need to allow the following commands in the sudoers file:

systemctl start <your-systemd-service>

systemctl stop <your-systemd-service>

systemctl restart <your-systemd-service>

systemctl enable <your-systemd-service>

dont use the service command.

Remember to replace the service name with your systemd service. For example if your service file is with name:

/etc/systemd/system/controller.service

then it should be:

systemctl start controller.service

systemctl stop controller.service

systemctl restart controller.service

systemctl enable controller.service

also , you will need to do:

systemctl daemon-reload

after you place you service file in systemd

Adding commonads in sudoers:

https://www.atrixnet.com/allow-an-unprivileged-user-to-run-a-certain-command-with-sudo/

example command:

<your-user> ALL=(ALL) NOPASSWD: /usr/bin/systemctl start controller.service

Comments

[George Udosen]

Your script is the issue!

[Matthew]

I see... How do I give the proper permissions to the script?

[George Udosen]

No, the "asking for password" is the issue and I assume controller is your script!

[Matthew]

server.js is my script that calls /home/pi/Documents/node_modules/rpio/lib/rpio.js

[Matthew]

I'm not sure what you mean by "no"...

[Matthew]

Where is the sudoers file?

[Ijaz Ahmad]

just type visudo as root , it will open the config file and u need to allow your user thoese commands

[Ijaz Ahmad]

remember to replace the service name with the name of your systemd service

[Matthew]

I get an error after I save the file, >>> /etc/sudoers: syntax error near line 15 and so on for each line I try to add.

[Matthew]

How do I edit as root when I'm logged in as another user?

[Ijaz Ahmad]

you need to check the syntax of how to add entries in sudoers file

[Ijaz Ahmad]

you need to be root to edit the sudoers file , or ask your system admin

[Ijaz Ahmad]

allowing commands in sudeors file doesnt mean that you just copy paste them , they have specifc syntax , i have just pointed out the commands u need to allow , how to allow them is a different question

[Matthew]

I can run sudo visudo... Is that good enough?

[Ijaz Ahmad]

atrixnet.com/…

[Matthew]

Even when running as root with su root then visudo I get a syntax error.

[Matthew]

Hm. Maybe it's slightly different on Raspbian?