EO Engineering Learning OS
PROJECT LADDER · P03
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CORE PROJECT · TARGET L3 · 4–5 days
P03

EC2 + systemd

Move the same application onto a Linux server and operate it as a supervised service.

01 / CONCEPT MAP

Know what the parts mean.

Learn each concept deeply enough to recognize it, place it in the system and reason about normal and failed behavior.

01

EC2 and SSH

Define it · locate it · observe it · explain its failure mode.

02

Ubuntu packages

Define it · locate it · observe it · explain its failure mode.

03

Uvicorn process

Define it · locate it · observe it · explain its failure mode.

04

systemd

Define it · locate it · observe it · explain its failure mode.

05

service logs

Define it · locate it · observe it · explain its failure mode.

02 / SYSTEM FLOW

Trace it end to end.

Engineer→SSH→EC2→systemd→Uvicorn→FastAPI

For every transition: identify input, output, identity, protocol, state, trust boundary, evidence and owner.

03 / GUIDED BUILD

Build, observe and explain.

Documentation and AI are allowed. The engineer must review every output and demonstrate the result from direct evidence.

  1. 01Launch and harden EC2 access
  2. 02Install dependencies
  3. 03Run Uvicorn manually
  4. 04Create application user
  5. 05Create systemd unit
  6. 06Verify restart and logs
04 / INCIDENT

The app works in the shell but fails under systemd due to user, path or environment differences.

Required investigation

State impact → collect evidence → form competing hypotheses → test the cheapest discriminator → isolate root cause → contain → correct → verify.

Evidence pack

Timeline, relevant logs/metrics, failed assumptions, root cause, correction, verification and one prevention action.

AI ownership

AI may suggest causes and commands. The engineer must explain why each check is safe, what result is expected and how the result changes the hypothesis.

05 / DESIGN CHALLENGE

Defend the decision.

Define host layout, runtime identity, service lifecycle and log ownership.

06 / VERIFY, SUBMIT & REVIEW

Submission evidence

Architecture review

  • Explain ec2 + systemd without relying on memorized commands.
  • Draw the flow and name what crosses every arrow.
  • Identify the most likely, highest-impact and hardest-to-detect failure.
  • Show the evidence that proves the solution works.
  • Defend one security, reliability and cost trade-off.

Definition of Done

  • Acceptance criteria pass
  • Flow is drawn and explained
  • Security implications considered
  • Logs/metrics checked
  • Failure is tested
  • AI output is understood
  • Runbook is reusable
  • Mentor review passes
07 / MENTOR GUIDE

Do not score memory. Score the engineer’s ability to form a model, collect evidence, make a safe change and defend the trade-off.

1 Cannot explain2 Understands with gaps3 Implements and troubleshoots4 Designs and reviews