ced4568andClaude Sonnet 5
e007bcf000
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]>
54 lines
1.4 KiB
Markdown
54 lines
1.4 KiB
Markdown
# Demonstration: Two Different Questions, Two Different Commands
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## OBSERVE
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```
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$ df -h /
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Filesystem Size Used Avail Use% Mounted on
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overlay 937G 199G 691G 23% /
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```
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The root filesystem overall: 23% used, plenty free.
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## HYPOTHESIS
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Predict: does this tell you anything about which specific directory is using the most space?
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## INSPECT
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```
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$ du -sh /var/log/* 2>/dev/null
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1.2M /var/log/nginx
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850K /var/log/k3s.log
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```
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No — `df` only ever answers "how full is this filesystem overall." Finding a SPECIFIC large
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consumer requires `du`, pointed at the directories you suspect.
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## CHANGE
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Narrow further into a single suspicious directory:
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```
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$ du -sh /var/log/nginx/*
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600K /var/log/nginx/access.log
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600K /var/log/nginx/error.log
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```
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## VERIFY
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You now know both the overall filesystem picture (`df`) AND exactly which files are contributing
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to it (`du`, narrowed progressively) — two genuinely different tools for two genuinely different
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questions, not interchangeable.
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## Instructor Notes
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**Demo goal:** Make the df/du distinction concrete by actually needing BOTH to answer a
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realistic "what's using my disk" question.
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**Approximate timing:** 8 minutes live.
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**Common mistake to watch for:** running `du -sh /` directly (extremely slow on a large
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filesystem, since it recurses everything) instead of narrowing progressively into suspected
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directories first.
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