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Creating systemd Services: Write Your Own

You can create your own systemd services. For custom applications. For scripts that need to run automatically.

Here's the thing: Creating services is useful. Learn it. You'll use it.

Service File Location​

/etc/systemd/system/              # System services (preferred)
/usr/lib/systemd/system/         # Package services
~/.config/systemd/user/          # User services

My take: Use /etc/systemd/system/ for custom services. It's the right place.

Basic Service File​

Simple Service​

# /etc/systemd/system/myservice.service
[Unit]
Description=My Custom Service
After=network.target

[Service]
Type=simple
ExecStart=/usr/local/bin/myservice
Restart=always
User=myuser

[Install]
WantedBy=multi-user.target

My take: This is a basic service file. Learn it. Use it.

Service Sections​

Unit: Service metadata

  • Description = What the service does
  • After = Start after these services

Service: How to run

  • Type = Service type (simple, forking, oneshot)
  • ExecStart = Command to run
  • Restart = Restart policy
  • User = Run as this user

Install: When to start

  • WantedBy = Start with this target

My take: Three sections. Unit. Service. Install. Learn them.

Common Service Types​

Type: simple​

[Service]
Type=simple
ExecStart=/usr/bin/myapp

My take: Simple service runs in foreground. Most common.

Type: forking​

[Service]
Type=forking
ExecStart=/usr/bin/myapp
PIDFile=/var/run/myapp.pid

My take: Forking service daemonizes. Use when app forks.

Type: oneshot​

[Service]
Type=oneshot
ExecStart=/usr/bin/myscript
RemainAfterExit=yes

My take: Oneshot runs once. Use for scripts.

Real-World Examples​

Python Application Service​

[Unit]
Description=Python Web Application
After=network.target

[Service]
Type=simple
User=www-data
WorkingDirectory=/var/www/app
ExecStart=/usr/bin/python3 /var/www/app/app.py
Restart=always
Environment="PORT=8080"

[Install]
WantedBy=multi-user.target

Script Service​

[Unit]
Description=Backup Script Service
After=network.target

[Service]
Type=oneshot
ExecStart=/usr/local/bin/backup.sh
User=backup

[Install]
WantedBy=multi-user.target

Enabling Services​

# Reload systemd
sudo systemctl daemon-reload

# Enable service
sudo systemctl enable myservice.service

# Start service
sudo systemctl start myservice.service

My take: Reload. Enable. Start. That's the process.

Common Mistakes (I've Made These)​

  1. Not reloading systemd: After creating service, reload systemd. daemon-reload

  2. Wrong ExecStart path: Use absolute paths. Relative paths don't work.

  3. Wrong user: Services run as root by default. Set user if needed.

  4. Not enabling: Services don't start on boot unless enabled. Enable them.

  5. Wrong Type: Choose the right type. Simple for most cases.

What's Next?​

Now that you can create services, let's talk about Timers And Cron for scheduled tasks.

Personal note: When I started, I'd run scripts manually. Then I learned systemd services. Now I create services for everything. They're reliable. They're automatic. Learn them.