32 min
Linux Core Subsystems: One-Page Reference Map
Overview This is a one-page cheat sheet for Linux kernel subsystems. Each subsystem controls a critical resource; understanding them is essential for troubleshooting, optimization, and security.
Why understanding subsystems matters:
Imagine your server is slow. Without subsystem knowledge, you’re guessing:
“Maybe add more RAM?” (might be CPU scheduler issue) “Maybe faster disk?” (might be memory cache problem) “Maybe more CPU?” (might be I/O scheduler misconfiguration) With subsystem knowledge, you diagnose systematically:
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October 16, 2025 · 32 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