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Creating a systemd Service in Debian

2024.01.28 ｜ Yuki Rea

A systemd service is a great way do manage processes or scripts that you wish to run automatically when a system starts. Creating a service is as easy as creating a .service file and enabling it.


Create a .service file

Create a .serivce file in your text editor of choice within /etc/systemd/system/
In this case, I created example.service 

/etc/systemd/system/example.service
 1 [Unit]
 2 Description=This is just an example service
 3 Wants=network-online.target
 4 After=network-online.target
 5 
 6 [Service]
 7 User=username
 8 Group=groupname
 9 WorkingDirectory=/home/user/
10 ExecStartPre=/usr/bin/pre-command
11 ExecStart=/usr/bin/command args
12 ExecStop=/usr/bin/command args
13 ExecReload=/usr/bin/command args /usr/bin/command
14 Restart=always
15 TimeoutSec=1800
16 
17 [Install]
18 WantedBy=multi-user.target

Service File Parameters

  • Description

      • A short description of what the service does.

  • Wants

      • The service will be started once it reaches this target. If the target fails, the service will be started anyway.

  • After

      • Wait until after this target to start the service.

  • User

      • Specify which user the service should run as.

  • Group

      • Specify which group the service should run as.

  • WorkingDirectory

      • Specify the working directory of the service if any.

  • ExecStartPre

      • Commands or scripts to run to prepare for starting the service.

  • ExecStart

      • Commands or script to start the service.

  • ExecStop

      • Commands or script to run when the service is stopped.

  • ExecReload

      • Commands or script to run when the service is restarted.

  • Restart

      • Should the service restart if it fails?

  • TimeoutSec

      • How long in seconds should we wait for the service to start before aborting.

For additional parameters, please see the following article from RedHat.
Managing Services with systemd


Start a Service

Once you have created your .service file, you should start it in order to test the service before enabling it. You can start your servic with the systemctl start example.service

Check the Status of a Service

You can check the status of a service using the following command. systemctl status example.service

systemctl status ssh.service
● ssh.service - OpenBSD Secure Shell server
     Loaded: loaded (/lib/systemd/system/ssh.service; enabled; preset: enabled)
     Active: active (running) since Sat 2024-01-27 19:35:03 CST; 17h ago
       Docs: man:sshd(8)
             man:sshd_config(5)
    Process: 682 ExecStartPre=/usr/sbin/sshd -t (code=exited, status=0/SUCCESS)
   Main PID: 701 (sshd)
      Tasks: 1 (limit: 9290)
     Memory: 1000.0K
        CPU: 44ms
     CGroup: /system.slice/ssh.service
             └─701 "sshd: /usr/sbin/sshd -D [listener] 0 of 10-100 startups"

Jan 27 19:35:02 T420s systemd[1]: Starting ssh.service - OpenBSD Secure Shell server...
Jan 27 19:35:03 T420s sshd[701]: Server listening on 0.0.0.0 port 22.
Jan 27 19:35:03 T420s sshd[701]: Server listening on :: port 22.
Jan 27 19:35:03 T420s systemd[1]: Started ssh.service - OpenBSD Secure Shell server.


Enable a Service

Once you have verified that your service is working as intended, you can enable it. Enabling a service allows it to start automaticlaly when the contitions in the .service file are met.

Enable a service using the systemctl enable example.serivce



Stop a Service

Stop a service using the systemctl stop example.serivce