Seonglae Chosystemd Diagnostic Tools
systemd provides several powerful utilities to analyze system boot performance, diagnose issues, and manage services. Here are the key diagnostic tools:
systemd-analyze
A comprehensive tool for analyzing system boot-up performance.
- Basic Performance Analysis
- Simple time summary:
systemd-analyze time - Service startup time breakdown:
systemd-analyze blame - User service analysis:
systemd-analyze --user blame - Critical path visualization:
systemd-analyze critical-chain
- Visual Representations
- Generate SVG timeline:
systemd-analyze plot > plot.svg - Create HTML visualization:
systemd-analyze plot > plot.html
Service Management
Disable unnecessary services to improve boot time:
Advanced Analysis with systemd-bootchart
For detailed boot process visualization:
Evolution from SysV Init
Until CentOS 6, SysV init was responsible for system initialization. After the kernel loaded into memory, the init process would execute first, running init scripts based on RunLevels and service configurations.
Key Improvements with systemd
- Modernized boot process management
- Comprehensive service management
- Process resource control using cgroups
- Sophisticated service process supervision
Essential systemd Commands
Successful
systemd integrated and improved the previously complex and inconsistent init scripts, introducing dependency management, service status signals (Type=notify), and providing migration tools for complete compatibility with existing init methods.
It consolidates logs into a single binary journal (journald) with automated compression and rotation management, and enables flexible service orchestration through timers (OnCalendar), socket activation, and various unit types.
Additionally, it supports service hardening through extensive security options (namespace isolation, system call filtering, etc.), and as a result, despite initial resistance, has become a core component of the Linux ecosystem.
