HOWTO Create a Service

Why do it this way?

• Your service will be watchdogged by systemd
• Your service will recover from network and power outages.
• It allows other members to help maintain your service, or disable it cleanly if it need attention.
• It's great for IRC bots

Working on Sally

All members have shell and admin access on sally.

   ssh [email protected]

You also have sudo (root user) access.

   sudo uname -a

Create Your Service Environment

Create a System Account for your Service

   sudo useradd strup -b /srv/ -m -r

The creates a user named strup. The -b indicates the base home directory is /srv/, and therefore the system accounts home directory is /srv/strup/

Working with SystemD

Create a unit file: /etc/systemd/system/strup.service

[Unit]
Description=Strup IRC bot

[Service]
Type=simple
User=strup
Group=strup
ExecStart=/usr/local/bin/ircbot
WorkingDirectory=/srv/strup/

[Install]
WantedBy=multi-user.target

Start Your Service and Check for Log Output

   sudo systemctl start strup.service
   sudo systemctl status strup.service

To follow log output:

   sudo journalctl -u strup.service -f

Initially, in my example, I see ircbot: /home/PS1/hef/projects/strup/irc/main.cpp:45: int main(int, char**): Assertion `file.is_open()' failed. because I havn't created a file yet.

Working with Service Files

If you tried to see your service user's home directory earlier, you may have noticed it didn't work. switch to your service accounts users.

   sudo su strup
   cd

My example requires a file from project gutenberg.

   wget http://www.gutenberg.org/cache/epub/11/pg11.txt

Don't forget to switch back to your normal user when done

   exit

Enabling Your Service

After verifying that the service is starting and running correctly:

   sudo systemctl status strup.service

Enable the service

   sudo systemctl enable strup.service

The service is now configured to start when the machine reboots.