Maxwell MorrisandClaude Sonnet 5
92c3ad3191
A teaching-first, single-cluster GitOps setup: Talos Linux + Argo CD with an app-of-apps layout, MetalLB pre-installed for real LoadBalancer IPs on bare metal, a demo app, and a progressive docs/ walkthrough with a CLAUDE.md tutor persona and guided bootstrap checklist. Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
92 lines
4.3 KiB
Markdown
92 lines
4.3 KiB
Markdown
# 08 — Growing up: what to add next
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Everything up to here is deliberately minimal — enough to understand the
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whole loop, nothing more. This doc is a map of the natural next steps, each
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with why you'd want it and roughly what it involves. None of it is built
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for you; each is its own project once you're ready.
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## More nodes
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Right now, one machine is both control plane and worker
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(`allowSchedulingOnControlPlanes: true` in
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[`talos/patch-controlplane.yaml`](../talos/patch-controlplane.yaml)). That's
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a single point of failure: if that machine dies, the cluster is gone.
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To grow beyond it:
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1. Boot a second machine from the Talos ISO, same as the first.
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2. Generate a **worker** config instead of a control-plane one — you
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already have `_out/worker.yaml` from
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[`docs/02-talos-bootstrap.md`](02-talos-bootstrap.md), unused until now.
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3. `talosctl apply-config --insecure --nodes <NEW_NODE_IP> --file _out/worker.yaml`
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4. `kubectl get nodes` should show two nodes shortly after.
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For real resilience against a control-plane node failing (not just adding
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worker capacity), you'd want an odd number of control-plane nodes — 3 is
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the normal minimum — because etcd (the cluster's data store) uses majority
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voting to agree on state, and majority voting needs an odd number to avoid
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ties. That's a bigger step than this doc covers in detail; ask Claude when
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you're actually ready to take it.
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## Ingress
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Right now, thanks to MetalLB ([`docs/05-metallb.md`](05-metallb.md)), the
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demo app gets its own dedicated IP address
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(see [`apps/demo/service.yaml`](../apps/demo/service.yaml)). That's a real
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improvement over NodePort, but it doesn't scale past a handful of apps
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either: every app still needs its own IP address out of a pool that's only
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so big, and there's no way to route by hostname (`app1.example.com` vs
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`app2.example.com` sharing one IP on port 443).
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An **Ingress controller** is itself just another app you'd deploy the same
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way as anything else in this repo (see
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[`docs/07-adding-new-apps.md`](07-adding-new-apps.md)) — commonly as a
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Helm-based app, since most ingress controllers are distributed that way,
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same as MetalLB. It typically sits behind one single MetalLB
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`LoadBalancer` Service (one IP, total, for every app), and you add an
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`Ingress` resource per app instead of giving each one its own
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`LoadBalancer` Service — trading "one IP per app" for "one IP, many
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hostnames."
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## cert-manager
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Once you have Ingress and real hostnames, you'll want HTTPS. `cert-manager`
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is the standard tool for this — it watches for certificate requests and
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automatically obtains and renews them (commonly via Let's Encrypt). Also
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just another app in this repo's structure once you get there.
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## Secrets management
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**This repo is public. Never commit a plaintext secret, credential, token,
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or private key to it — anyone can read your Git history, forever, even if
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you delete the file in a later commit.**
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Kubernetes' own `Secret` resource does not encrypt anything — it just
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base64-encodes data, which is not encryption, only encoding (trivially
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reversible by anyone). None of the manifests in this repo need secrets yet,
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which is exactly why this hasn't come up so far. When you add something
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that does (a database password, an API key), you need one of:
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- **[Sealed Secrets](https://github.com/bitnami-labs/sealed-secrets)** —
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encrypts a secret using a key that only your cluster holds, producing a
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`SealedSecret` file that's safe to commit; the cluster decrypts it into a
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normal Secret on the fly.
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- **[SOPS](https://github.com/getsops/sops)** (often paired with Argo CD via
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a plugin) — encrypts values inside a normal-looking YAML file using a key
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from a system like age or a cloud KMS, decrypted at sync time.
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Either is a reasonable choice; don't improvise your own approach. Ask
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Claude to walk you through setting one up when you have a real secret to
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manage — it's a short, well-trodden path once you're at that point.
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> **Ask Claude:** if you're about to commit anything you're even slightly
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> unsure about, paste it (or describe it) and ask first. Cheaper than a
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> `git filter-branch` later.
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## Where to go from here
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You've now seen the whole shape: Talos underneath, Argo CD watching Git,
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app-of-apps organizing what it manages. Everything in this doc is more of
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the same pattern — a new app, a new file, a push. Pick whichever expansion
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is actually useful to you and start there.
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