DevOps4UA

Kubernetes Services & Ingress. project #1

Jenkins

Source: Dev.to | Jan 11, 2026 (UTC)

PREREQUISITES (ONCE)

minikube start kubectl get nodes

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Expected:

minikube Ready

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BASE APP (USED FOR ALL PROJECTS)

One app. Same Pods. Only networking changes.

apiVersion: apps/v1 kind: Deployment metadata: name: demo-app spec: replicas: 3 selector: matchLabels: app: demo template: metadata: labels: app: demo spec: containers: - name: app image: hashicorp/http-echo:0.2.3 args: - "-listen=:8080" - "-text=HELLO FROM POD" ports: - containerPort: 8080

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kubectl apply -f deployment.yaml kubectl get pods

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PROJECT 1 — ClusterIP (Internal Only)

What This Proves

✔ Services give stable internal networking
✔ Pod IPs change — Service never changes

Create ClusterIP

apiVersion: v1 kind: Service metadata: name: demo-clusterip spec: selector: app: demo ports: - port: 80 targetPort: 8080

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kubectl apply -f svc-clusterip.yaml kubectl get svc

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Test (Correct Way)

kubectl run test --rm -it --image=busybox -- sh wget -qO- demo-clusterip

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PROD ISSUE #1 — No endpoints

kubectl get endpoints demo-clusterip

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Cause

Fix

kubectl get pods --show-labels kubectl edit svc demo-clusterip

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DevOps Takeaway

ClusterIP is the backbone of Kubernetes.
If this fails — nothing works.

PROJECT 2 — NodePort (Why It Is Dangerous)

What This Proves

✔ NodePort opens ports
❌ Does NOT provide routing, HA, or stable IP

Create NodePort

apiVersion: v1 kind: Service metadata: name: demo-nodeport spec: type: NodePort selector: app: demo ports: - port: 80 targetPort: 8080 nodePort: 30080

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kubectl apply -f svc-nodeport.yaml kubectl get svc

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Access

minikube ip curl http://<MINIKUBE-IP>:30080

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PROD ISSUE #1 — Random failures

kubectl delete pod -l app=demo

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Still works?
YES → kube-proxy reroutes

Now imagine node deleted in cloud → ❌ DEAD

PROD ISSUE #2 — Port blocked

In Minikube:
✔ works

In cloud:
❌ security group missing port

DevOps Verdict

Use

Verdict

Learning

✅

Debug

✅

Production

❌

PROJECT 3 — LoadBalancer (Minikube Style)

What This Proves

✔ Kubernetes requests LB
✔ Minikube simulates cloud LB

Create LoadBalancer

apiVersion: v1 kind: Service metadata: name: demo-lb spec: type: LoadBalancer selector: app: demo ports: - port: 80 targetPort: 8080

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kubectl apply -f svc-lb.yaml kubectl get svc

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VERY IMPORTANT (Minikube Only)

minikube tunnel

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Keep terminal open.

Now:

kubectl get svc demo-lb

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You will see:

EXTERNAL-IP: 127.0.0.1

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curl http://127.0.0.1

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PROD ISSUE #1 — EXTERNAL-IP pending

Cause

Fix

minikube tunnel

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PROD ISSUE #2 — LB exists but no traffic

kubectl describe svc demo-lb kubectl get endpoints demo-lb

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Cause

DevOps Verdict

✔ Simple external apps
❌ Expensive in real cloud
❌ One LB per service

PROJECT 4 — Ingress (REAL PRODUCTION MODEL)

What This Proves

✔ Ingress is external traffic brain
✔ One IP → many apps

STEP 1 — Enable Ingress in Minikube

minikube addons enable ingress kubectl get pods -n ingress-nginx

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Wait until:

ingress-nginx-controller Running

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STEP 2 — ClusterIP for Ingress

apiVersion: v1 kind: Service metadata: name: demo-ingress-svc spec: selector: app: demo ports: - port: 80 targetPort: 8080

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STEP 3 — Ingress Rule

apiVersion: networking.k8s.io/v1 kind: Ingress metadata: name: demo-ingress spec: rules: - host: demo.local http: paths: - path: / pathType: Prefix backend: service: name: demo-ingress-svc port: number: 80

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STEP 4 — DNS (Local)

minikube ip sudo nano /etc/hosts

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Add:

<MINIKUBE-IP> demo.local

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Test

curl http://demo.local

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PROD ISSUE #1 — 404 from Ingress

kubectl describe ingress demo-ingress

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Cause

PROD ISSUE #2 — Ingress OK, app broken

kubectl get endpoints demo-ingress-svc kubectl get pods

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Cause

PROD ISSUE #3 — Ingress controller down

kubectl get pods -n ingress-nginx kubectl logs -n ingress-nginx <controller-pod>

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FINAL DEVOPS MENTAL MODEL (MINIKUBE OR PROD)

Client | v Ingress (routing rules) | v Service (ClusterIP) | v Pod

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FINAL SUMMARY TABLE

Component

Purpose

Who Provides It

ClusterIP

Internal networking

Kubernetes

NodePort

Port exposure

Kubernetes

LoadBalancer

External IP

Cloud / Minikube

Ingress

Routing + TLS

Kubernetes

Egress

Outbound traffic

Cloud / NAT

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