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6.5 · Lessons from the field

Level 6 · In practice

6.5Lessons from the field

Goal: benefit from practitioners' aggregated experience, with no folklore.
Estimated time: 9 min · If you only have 5 min: read “The essentials in 30s” + the diagram.

The essentials in 30 seconds

  • Prevent: .dockerignore from the very first Dockerfile, healthcheck + retry, immutable tags — cheapest is to avoid.
  • Prove: replayed backup, down/up with no loss, early proxy — what is not proven does not exist.
  • Doubt: latest in prod, never-replayed dumps and messy ports always bite — no myths.

Idir's thread — what the quarter taught him

After one quarter, Idir sums up his practice in Algiers in five sentences: write the .dockerignore first, require the healthcheck, ban latest in prod, believe only replayed backups, set up the proxy early. And the golden rule on the wall: what is not versioned, proven and tested does not exist.

Keep one principle and dismiss one myth: that is how experience settles in.

What practitioners recommend

Anonymous synthesis of widely shared best practices from the official documentation, community feedback and operations guides (no fabricated quotes: what follows aggregates public, verifiable recommendations).

✓ To do

  • "The .dockerignore first": what never enters the context breaks neither the cache nor security.
  • "The healthcheck changes everything": switching to a healthy condition + retry makes startup crashes disappear.
  • "Immutable tags in prod": the cheapest insurance against the rebuild that breaks everything on a Friday evening.
  • "The tested backup, not the backup": test volume + verification, otherwise it is an illusion.
  • "A proxy early": from the second app on, to avoid port debt and prepare TLS and logs.

✗ To avoid

  • "latest in prod, we'll see" — no: a harmless rebuild pulls a major version and breaks everything.
  • "My dump runs, so I'm safe" — no: with no replayed restore, it is an illusion.
  • "depends_on is enough, no need for a healthcheck" — no: with no healthy condition or retry, crashes come back.
  • "One port per app, we'll handle it later" — no: with no early proxy, port debt explodes.
Common misinterpretation: "this feedback is quotes". No. This is an anonymous synthesis of widespread best practices, not attributed statements: for named opinions, rely on real, sourced references.
Text version of the diagram (SEO / screen readers / translation): Experience cap: 1) Prevent — .dockerignore from the first Dockerfile, healthcheck + retry, immutable tags. 2) Prove — replayed backup, down/up with no loss, versioned and tested. 3) Prepare — proxy from the second app, TLS, logs, routing without rewriting. 4) Dismiss — latest in prod, never-replayed dump, lone depends_on, messy ports. Lesson: what is not versioned, proven and tested does not exist.

Ready-to-say script — speaking as a practitioner (30 s)

"My context: [.dockerignore from the start]. My reliability: [healthcheck + retry, 1.0 tags]. My proof: [replayed backup, down/up with no loss]. My exposure: [early proxy, TLS, logs]."

Copy-paste template — practitioner ritual (5 lines)

docker compose config
docker compose up -d --build
docker compose ps
docker compose logs -f api
docker system df

Small business / tight budget

One principle per quarter is enough: .dockerignore + healthcheck first, the rest after.

SME in Algiers

Adapt to local releases: replayed backup and down/up proof at each milestone.

Remote / hybrid

Prioritise written traces remotely (validated config, replayed proof, dated tags).

Intercultural

Prioritise local transposition as soon as codes differ: ask peers, compare practices.

Caution: Generic reminder: this feedback is an anonymous synthesis of best practices — not attributed quotes; for named opinions, rely on real, sourced references.

48h challenge — apply tomorrow

Apply 1 practitioner principle (.dockerignore, healthcheck, 1.0 tags, replayed backup, early proxy) to your current stack and dismiss 1 myth.

Section exit checklist
  • I know the practitioners' 5 principles and the 4 myths to dismiss.
  • My practitioner ritual (prevent, prove, prepare) is started.
  • I did the 48h challenge or scheduled its date.
Self-rating 1-5: clarity of my principles?myths dismissed?
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Check your understanding

Idir wants to grow like the practitioners. What does the field say?

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Experience cannot be bought: it is built by versioning, proving and testing, stack after stack.