World K3: Counters & Doors

Every pod gets an IP

You will learn: how pods reach each other, and why their addresses change.

Checked with Kubernetes 1.37 on 31 Oct 2026

The problem

You are here: cluster kind-dev namespace default

~/shop $ kubectl get pods -o wideNAME                   READY   STATUS    RESTARTS   AGE   IP           NODE          NOMINATED NODE   READINESS GATESclient                 1/1     Running   0          22s   10.244.2.3   dev-worker2   <none>           <none>shop-94c9756fd-8tghh   1/1     Running   0          22s   10.244.1.3   dev-worker    <none>           <none>shop-94c9756fd-hjttw   1/1     Running   0          22s   10.244.2.4   dev-worker2   <none>           <none>shop-94c9756fd-pklq2   1/1     Running   0          22s   10.244.1.4   dev-worker    <none>           <none>

The client tray is hungry. Three shop trays can cook. How does the client reach one of them?

Watch

Tap each point on the timeline.

Every pod gets its own . Think of a table number for each tray. Tap each step.

Watch

You are here: cluster kind-dev namespace default

~/shop $ kubectl exec client -- wget -qO- -T 5 http://10.244.1.4<h1>Kedai Kancil</h1>

kubectl exec client -- wget … runs wget inside the client tray. It calls one shop tray straight by its IP. The page comes back.

Try it

Delete one shop tray. Then look at the IP column again.

You are here: cluster kind-dev namespace default

dev-control-planeOpenManager

No trays here.

dev-workerOpen

shop·8tghh
shop·pklq2

dev-worker2Open

client
shop·hjttw

Time: +0s (sped up)

Hint

kubectl delete pod <name> throws one tray away. kubectl get pods -o wide shows the IPs.

Predict

The new tray got a new IP. The client saved the old one. What happens to its next order?

Check

Pod IPs change. Judge each habit.

Swipe right for good, left for needs work. Or use the buttons.

1 / 4

Expect a new IP when a pod is replaced.

You did it!

You can now explain pod IPs, and why they change.

Go deeper (optional)

Each stall hands out IPs from its own range, like 10.244.1.0/24 on dev-worker. A network plugin (CNI) does this work. You meet it in lesson 11.

Real rep (optional), on a throwaway kind cluster:

Real mission

Read your "you are here" sign first. It should say kind-dev.
kubectl config current-context
Start three shop trays.
kubectl create deployment shop --image=nginx:1.29-alpine --replicas=3
Note each IP and stall.
kubectl get pods -o wide
Delete one shop pod. Look again: new name, new IP.

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