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Level 3 · Delivery & Release Engineering

Level 2 made the pipeline good at building and testing. Level 3 is about the last mile: getting a change into production safely, being able to undo it, and knowing whether your delivery process is healthy.

What was run, and what wasn't

No deployment, Kubernetes cluster, cloud account, Terraform, Argo CD or signing tool was used. What was run, on macOS: a canary-release simulator with statistics (11 tests), a feature-flag evaluator with deterministic rollout (8 tests), real SQLite schema-migration experiments (expand/contract, including an unexpected failure), a GitOps reconcile loop (8 tests), a plan guard on hand-written plan fixtures (9 tests), a Conventional-Commits version tool (12 tests), a DORA-metrics calculator on a hand-made fixture (6 tests), and a checksum tamper demo. Everything about real platforms comes from documentation or general knowledge, and is labelled as such.

Prerequisites: Levels 1 and 2.

Modules

  1. Deployment Strategies: recreate, rolling, blue-green, canary, and a measured canary analysis.
  2. Feature Flags: deploy versus release, deterministic percentage rollout, flag debt.
  3. Database Migrations: expand and contract, run on SQLite, including the failures.
  4. Rollbacks: what can be undone and what cannot; roll-forward.
  5. Infrastructure Pipelines: plan, review, apply, state, drift, a destructive-change guard.
  6. GitOps: pull-based reconciliation shown with a tested simulator.
  7. Release Management: semantic versions, Conventional Commits, hotfixes, trains.
  8. Supply-Chain Security: pins, checksums, SBOM, signing, provenance.
  9. DORA Metrics: four delivery measures, computed and how they are gamed.
  10. Project: A Canary Simulator: false-alarm and detection rates across scenarios.

After Level 3

Level 4 is about running delivery at scale: threat-modelling the pipeline, speed and cost, Jenkins and Actions fleets, audit and compliance, testing the pipelines themselves, incident response, migrating CI systems, golden paths and a capstone delivery platform.