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.
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October 16, 2025 · 17 min · DevOps Engineer
11 min
Linux Observability: Metrics, Logs, eBPF Tools, and 5-Minute Triage
Executive Summary Observability = see inside your systems: metrics (CPU, memory, I/O), logs (audit trail), traces (syscalls, latency).
This guide covers:
Metrics: node_exporter → Prometheus (system-level health) Logs: journald → rsyslog/Vector/Fluent Bit (aggregation) eBPF tools: 5 quick wins (trace syscalls, network, I/O) Triage: 5-minute flowchart to diagnose CPU, memory, I/O, network issues 1. Metrics: node_exporter & Prometheus What It Is node_exporter: Exposes OS metrics (CPU, memory, disk, network) as Prometheus scrape target Prometheus: Time-series database; collects metrics, queries, alerts Dashboard: Grafana visualizes Prometheus data Install node_exporter Ubuntu/Debian:
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October 16, 2025 · 11 min · DevOps Engineer
🛠️ Guide
12 min
Kubernetes Troubleshooting: Pod Crashes, Networking, and Resources
Introduction Kubernetes troubleshooting can be challenging due to its distributed nature and multiple abstraction layers. This guide covers the most common issues and systematic approaches to diagnosing and fixing them.
Pod Crash Loops Understanding CrashLoopBackOff What it means: The pod starts, crashes, restarts, and repeats in an exponential backoff pattern.
Diagnostic Process Step 1: Check pod status
kubectl get pods -n production # Output: # NAME READY STATUS RESTARTS AGE # myapp-7d8f9c6b5-xyz12 0/1 CrashLoopBackOff 5 10m Step 2: Describe the pod
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October 15, 2025 · 12 min · DevOps Engineer