17 min
Linux Boot Flow & Debugging: From Firmware to systemd
Executive Summary Linux boot is a multi-stage handoff: UEFI → Bootloader → Kernel → systemd → Targets → Units. Each stage has failure points. This guide shows the sequence, where failures occur, and how to capture logs.
Why understanding boot flow matters:
When a Linux server won’t boot, you need to know WHICH stage failed to fix it effectively. A black screen could mean anything from bad hardware to a typo in /etc/fstab.
…
October 16, 2025 · 17 min · DevOps Engineer
9 min
Linux Production Guide: Kernel Subsystems, Systemd, and Best Practices
Executive Summary Linux is a layered system: from firmware through kernel subsystems to containerized applications. Understanding these layers—and their interdependencies—is critical for reliable, secure, performant infrastructure.
This guide covers:
Layered architecture (firmware → kernel → userspace → containers) Core subsystems: process scheduling, memory, filesystems, networking systemd: unit management and service lifecycle Production best practices: security, reliability, performance, observability Note: For detailed boot flow and debugging, see the Linux Boot Flow & Debugging guide.
…
October 16, 2025 · 9 min · DevOps Engineer
12 min
Linux Security Baseline for Production Servers
Executive Summary A security baseline is the foundation: OS-hardened, patched, with restricted access and audit trails. This guide covers minimal-install servers with hardened SSH, firewall (default-deny), LSM enforcement, least-privilege sudo, audit logging, and systemd hardening.
Goal: Reduce attack surface, detect breaches, and enforce privilege boundaries.
1. Minimal Install & Patching Minimal Install What it is:
Install only required packages (base + SSH + monitoring agent) No GUI, X11, unnecessary daemons Reduces vulnerabilities (fewer packages = fewer CVEs) Install steps (Ubuntu/Debian):
…
October 16, 2025 · 12 min · DevOps Engineer