World K3: Counters & Doors

HTTPRoute: signboards to stalls

You will learn: to send each path to the right Service with HTTPRoute rules.

Checked with Kubernetes 1.37 on 31 Oct 2026

The problem

You are here: cluster kind-dev namespace default

~/shop $ curl -s http://172.18.0.200/api/menu<html><head><title>404 Not Found</title></head><body><center><h1>404 Not Found</h1></center><hr><center>nginx/1.29.8</center></body></html>

The menu API lives at /api. But every order lands at the shop counter. The shop has no /api/menu, so it says 404.

Watch

Tap each point on the timeline.

An holds the signboards. Each rule is a path, then a Service. The most specific sign wins.

Try it

routes.yaml adds this sign. Apply it, then ask for /api/menu again.

    - matches:
        - path:
            type: PathPrefix
            value: /api
      backendRefs:
        - name: api
          port: 80

You are here: cluster kind-dev namespace default

Entrance entrance 172.18.0.200/ → shop

api2/2 ready
shop3/3 ready

dev-control-planeOpenManager

No trays here.

dev-workerOpen

api·w7hql
shop·hl847
shop·qcgst

dev-worker2Open

api·lrtxv
shop·pm62t

Time: +0s (sped up)

Check

Mei wrote her own /api sign. It won’t apply. Fix it.

Fix the manifest, then press Apply.

route.yaml16 lines

Plain words: a path must start with /.

Predict

Which mistake makes the entrance answer 500? Try the breaks, one at a time.

Break one hop so the user gets: 500 Internal Server Error.

BrowserGET /api/menu on port 80
Gateway (entrance)entrance listens on :80
HTTPRoute (signboard)/api → api:80
Service (order number)api: port 80 → 8080
EndpointSlice (ready trays)2 ready of 2
Pod (tray)api-6d8f7b9c5d-k2x8p listens on :8080

Break something

Check

Two signs: PathPrefix /api and PathPrefix /. Where does each order go?

Drag a card into a box. Or tap the card, then tap the box.

You did it!

You can now send each path to the right Service.

Go deeper (optional)

Rules can also match hostnames and headers. Two backendRefs with weights, like 90 and 10, make a canary. Filters can redirect HTTP to HTTPS. kubectl describe httproute shows ResolvedRefs: a missing Service shows BackendNotFound.

Real rep (optional), on your kind cluster with a Gateway controller:

Real mission

Run two small apps, each with a Service.
Write one HTTPRoute with a / rule and an /api rule.
curl / and /api/menu. Each should reach its own app.
Read the route’s conditions.
kubectl describe httproute

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