PlatformEngr® Fleet GitOps course

Cheat notes · Module 00 · Orientation

Orientation: the platform you will run

A five-minute review for when you have done this module and want it back in your head. Open the full module for the steps and the lab, or the full text to print.

The idea

A platform team and a product team share a fleet of clusters, and every change either makes travels the same journey: issue, pull request, checks, approval, merge, then Argo CD reconciles it until it is healthy.

Remember

  • Two roles: the platform team owns clusters, Argo CD, policies and the namespace baseline. Product teams (team-checkout) own their deployment config. CODEOWNERS turns that split into review rules.
  • The change journey: requested, proposed, validated, previewed, approved, merged, reconciled, healthy. Each module practises some of these steps.
  • Reference repo vs your repo: the reference is the finished fleet. Your repo starts empty and takes one folder at a time from it, by pull request. Argo CD watches your repo, never the reference.
  • Required vs flexible: GitHub (issues, pull requests, Actions) and Git as the source of truth are required. Where Kubernetes runs is flexible: kind by default, AKS, EKS, GKE or any cluster.
  • End result vs full course: the quick start builds the finished fleet in 30 minutes as a preview; the course builds it piece by piece and explains each piece.

Pitfalls

  • Changing things with kubectl because it is quicker. The fleet only changes reliably through the repo Argo CD watches; the habit is the lesson.
  • Pointing Argo CD at the reference repo: you cannot merge there, so your pushes do nothing.

Test yourself

Answer in your head first, then open the answer.

Why does Argo CD watch your repo and not the reference repo?

GitOps is pull-based. You change the fleet by merging into the repo it watches, so it must be one you can merge into.

Who owns a product's namespace baseline (quota, network policy, RBAC)?

The platform team. Product teams consume it; that is what makes it consistent.

How does the quick start differ from the full course?

Same fleet. The quick start creates it from the template; the course builds and explains each piece.

Where module 00 leaves you: Nothing is built yet. Your details are saved in the course, every tool is checked, and you know what you are about to build and in which order.