Introduction
In modern Linux distributions, Systemd is the default init system responsible for booting the system, managing services, and handling logging. As a DevOps engineer, mastering Systemd is crucial for managing background services efficiently. In this guide, we’ll cover essential Systemd commands and best practices for service management.
What is Systemd?
Systemd is a system and service manager for Linux. It initializes the system at boot and manages processes. Unlike older init systems like SysVinit, Systemd is faster, parallelized, and more feature-rich.
Key Features of Systemd:
- Faster boot times with parallel service execution
- Better service dependency management
- Centralized logging with
journalctl - Built-in tools for monitoring & managing services
Essential Systemd Commands for Service Management
Systemd services are controlled using the
Systemd services are controlled using the
systemctl command. Here are the most used commands:# Start a service
sudo systemctl start nginx
# Stop a service
sudo systemctl stop nginx
# Restart a service
sudo systemctl restart nginx
# Check service status
sudo systemctl status nginx
Tip: The
status command helps debug why a service isn’t running correctly.Enable and Disable Services at Boot
To make a service start automatically at boot, use: sudo systemctl enable nginx
To prevent a service from starting at boot: use sudo systemctl disable nginx
To check if a service is enabled: systemctl is-enabled nginx
To make a service start automatically at boot, use: sudo systemctl enable nginx
To prevent a service from starting at boot: use sudo systemctl disable nginx
To check if a service is enabled: systemctl is-enabled nginx
Checking Systemd Logs (journalctl)
Systemd logs all service activity using journalctl. This is useful for debugging failures.
View logs for a specific service: journalctl -u nginx --no-pager
View logs from the last boot: journalctl -b -u nginx
View logs from the last boot: journalctl -b -u nginx
Follow live logs : journalctl -u nginx -f
Creating a Custom Systemd Service
You can create custom services using Systemd. Let’s create a simple service that runs a Python script on boot.
You can create custom services using Systemd. Let’s create a simple service that runs a Python script on boot.
Step 1: Create a Service File
Create a file in
/etc/systemd/system/: sudo nano /etc/systemd/system/myscript.serviceAdd the following content:
Conclusion
[Unit]
Description=My Custom Script
After=network.target
[Service]
ExecStart=/usr/bin/python3 /home/user/myscript.py
Restart=always
User=user
[Install]
WantedBy=multi-user.target
Step 2: Enable and Start the Service
sudo systemctl daemon-reload
sudo systemctl enable myscript
sudo systemctl start myscript
Conclusion
Mastering Systemd is essential for managing Linux services efficiently. Whether you're deploying web servers, automating tasks, or debugging failures, Systemd simplifies service management.
Next Steps:
✅ Practice Systemd commands on a test server
✅ Create a custom service to automate a task
✅ Learn more about Systemd timers (alternative to cron jobs)
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