Systemd Cheatsheet

Systemd is a system and service manager for Linux, with systemctl being its primary command-line utility.

Basic service management involves controlling the lifecycle of systemd units, particularly services. These commands allow administrators to start, stop, enable, and monitor services across the system.

Advanced systemctl operations allow administrators to customize service behavior, establish dependencies between services, and optimize resource allocation. These techniques are essential for fine-tuning system performance and ensuring services work together properly.

System state management with systemctl involves controlling the overall system state, including boot targets, power operations, and recovery modes. Systemd targets replace traditional runlevels, providing a more flexible way to define system states.

Systemd provides powerful tools for diagnosing service issues. Journalctl offers centralized logging, while systemctl status reveals detailed service state information. These tools help identify failures, resource issues, and dependency problems in systemd services.

Unit files define services, sockets, mounts, and other resources managed by systemd. Understanding how to create and modify these files gives administrators precise control over system behavior and service configuration.

Systemd offers powerful tools to optimize system performance through parallel service startup, socket activation, resource control, and strategic timeout configuration. These techniques can significantly reduce boot time and improve resource utilization.

Systemd provides powerful security features to harden services through isolation, capability restrictions, and sandboxing. These techniques help minimize the attack surface and contain potential security breaches.