ced4568andClaude Sonnet 5
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Adds all 6 ROOT 02 modules (Linux system administration, storage & filesystems, the Networking Mental Model, Linux network inspection, DNS & HTTP, Linux troubleshooting) — 37 activities, each with a real lesson, demonstration/guided exercise, knowledge check, hands-on Lab, and reflection. The Networking Mental Model module (M3) gets deliberately extra depth per its "critical module" designation, with no lab by design — conceptual mastery via knowledge check and guided exercise, matching root-05-m00's own precedent. Adds 6 new hands-on Linux/networking scenarios plus 2 MCQs: linux-service-inspection (inspects the platform's own real nginx without touching it — a genuinely safe, real service-inspection target that avoids ever risking the Lab's own connectivity), linux-service-lifecycle (start/ verify/stop a fully controllable service), linux-storage-inspection, linux-network-inspection (ip/ss/getent/curl, each framed as answering one specific diagnostic question), linux-dns-http-diagnosis (a genuine DNS-resolves-but-wrong-port failure, diagnosed and fixed), and linux-troubleshooting-framework (a real missing-config-file failure, resolved via the RootNode Observe/Evidence/Hypothesis/Test/Repair/Validate/Prevent framework). All tested end-to-end via the real scenario-validation API, including negative tests confirming they fail when unsolved. Wires rootnode-linux-networking-assessment (2 required + 4 random-draw scenarios) using the existing Phase 3B assessment engine. Co-Authored-By: Claude Sonnet 5 <[email protected]>
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Reflection: You Fixed the Real Problem, Not the Suspected One
Reflection questions
- Before running any commands in this module's Lab, what would you have guessed was broken? Was your guess right?
- Why does correctly categorizing a failure (DNS vs. routing vs. TCP vs. application) matter more than just "trying things until something works"?
Real Ops takeaway
"DNS must be broken" is one of the most common wrong first guesses in real incident response — and disproving or confirming it takes seconds, not minutes. The habit this module builds — categorize the failure precisely before attempting a fix — is what separates a five-minute diagnosis from an hour of trying unrelated things. This exact reasoning, applied to Kubernetes Services/Ingress/DNS later, is one of the most valuable transferable skills in this entire program.
This module is complete. Continue to the final module of this course.
Instructor Notes
Discussion questions for a live classroom: question 1 works well as a live poll before revealing the Lab's actual root cause — the gap between instinct and evidence is the lesson.
Approximate timing: 5-8 minutes live discussion; 5 minutes self-paced writing.