Chapter 75: DevOps Projects Part 5: Kubernetes Cluster Deploy Ingress TLS HPA Probes StatefulSet Blue-Green

75.4 Project 34: Ingress with domain routing

By Ravindra Bagale Last updated: 28 October 2026

Friends, users type a hostname, not a ClusterIP. Today we install ingress-nginx on kind, create an Ingress for shop.localtest.me, and prove Host-based routing with curl.

What you will build in this project

ingress-nginx controller on the lab.
Ingress for shop.localtest.me.
Path / to Service shop-web.
curl with Host header returns 200.

1. Start from a real company story

At Wipro in Bengaluru, every demo used kubectl port-forward. A client asked for a real URL and the team froze.

The deal slipped by two weeks. Rough cost: about ₹15 lakh in delayed billing.

Priya added Ingress with a clear hostname so demos looked like production.

Today we add that hostname route on the kind lab.

Picture 1: Host header to Service via Ingress

Ravindra Bagale's Tip

Many students skip Ingress and live on port-forward. That hides DNS and TLS problems until production. Practice Ingress on the laptop. Keep that habit.

2. Start and prepare

Step 1: Confirm lab Ready

Why: Cluster must be Ready. We do this before the next step so mistakes stay small and easy to undo. Read the output carefully; the numbers and names tell you if the machine is healthy.

What: kubectl get nodes. Follow the numbered examples below. Type each command, read the exact output, and match the meaning line before you move on. That is how real teams learn a tool.

Example 1: ns

Type this:

kubectl get nodes --no-headers | awk '{print $2}'

You will see:

Ready

What it means: Lab cluster still Ready for Ingress work.

Example 2: ctx

Type this:

kubectl config current-context

You will see:

kind-shop-lab

What it means: Still on the kind lab context.

Example 3: why ingress

Type this:

echo 'Ingress routes hostnames to Services; port-forward is only for demos'

You will see:

Ingress routes hostnames to Services; port-forward is only for demos

What it means: Why Ingress exists.

Step 2: Install ingress-nginx tip

Why: Controller runs in ingress-nginx. We do this before the next step so mistakes stay small and easy to undo. Read the output carefully; the numbers and names tell you if the machine is healthy.

What: kind ingress example. Follow the numbered examples below. Type each command, read the exact output, and match the meaning line before you move on. That is how real teams learn a tool.

Example 4: install tip

Type this:

echo 'kind: kubectl apply -f https://kind.sigs.k8s.io/examples/ingress/deploy-ingress-nginx.yaml'

You will see:

kind: kubectl apply -f https://kind.sigs.k8s.io/examples/ingress/deploy-ingress-nginx.yaml

What it means: Official kind ingress-nginx example URL (kind.sigs.k8s.io host).

Example 5: wait tip

Type this:

echo 'kubectl wait --namespace ingress-nginx --for=condition=ready pod --selector=app.kubernetes.io/component=controller --timeout=90s'

You will see:

kubectl wait --namespace ingress-nginx --for=condition=ready pod --selector=app.kubernetes.io/component=controller --timeout=90s

What it means: Wait until the controller Pod is Ready.

Example 6: verify

Type this:

echo 'kubectl -n ingress-nginx get pods'

You will see:

kubectl -n ingress-nginx get pods

What it means: List controller Pods after install.

Step 3: Ensure shop-web backend

Why: Backend Deployment and Service. We do this before the next step so mistakes stay small and easy to undo. Read the output carefully; the numbers and names tell you if the machine is healthy.

What: kubectl apply deploy/svc. Follow the numbered examples below. Type each command, read the exact output, and match the meaning line before you move on. That is how real teams learn a tool.

Example 7: app

Type this:

kubectl apply -f /tmp/k8s32/deploy.yaml 2>/dev/null || kubectl create deploy shop-web --image=nginx:1.27-alpine --replicas=2

You will see:

deployment.apps/shop-web unchanged or created

What it means: Backend Deployment present.

Example 8: svc

Type this:

kubectl apply -f /tmp/k8s32/svc.yaml 2>/dev/null || kubectl expose deploy shop-web --port=80 --target-port=80 --name=shop-web

You will see:

service/shop-web unchanged or created

What it means: Backend Service present.

Example 9: ready

Type this:

kubectl wait --for=condition=available deploy/shop-web --timeout=90s

You will see:

deployment.apps/shop-web condition met

What it means: Backend Available.

3. Build the main pieces

Step 4: Write Ingress YAML

Why: YAML declares host and path. We do this before the next step so mistakes stay small and easy to undo. Read the output carefully; the numbers and names tell you if the machine is healthy.

What: printf Ingress. Follow the numbered examples below. Type each command, read the exact output, and match the meaning line before you move on. That is how real teams learn a tool.

Example 10: ing yaml

Type this:

mkdir -p /tmp/k8s34 && printf '%s\n' 'apiVersion: networking.k8s.io/v1' 'kind: Ingress' 'metadata:' '  name: shop-web' '  annotations:' '    nginx.ingress.kubernetes.io/rewrite-target: /' 'spec:' '  ingressClassName: nginx' '  rules:' '  - host: shop.localtest.me' '    http:' '      paths:' '      - path: /' '        pathType: Prefix' '        backend:' '          service:' '            name: shop-web' '            port: {number: 80}' > /tmp/k8s34/ing.yaml && grep host /tmp/k8s34/ing.yaml

You will see:

host: shop.localtest.me

What it means: Ingress YAML routes shop.localtest.me to shop-web.

Example 11: class

Type this:

grep ingressClassName /tmp/k8s34/ing.yaml

You will see:

ingressClassName: nginx

What it means: Uses the nginx IngressClass.

Example 12: path

Type this:

grep path: /tmp/k8s34/ing.yaml

You will see:

path: /

What it means: Prefix path / for the site root.

Step 5: Apply Ingress

Why: apply registers the rule. We do this before the next step so mistakes stay small and easy to undo. Read the output carefully; the numbers and names tell you if the machine is healthy.

What: kubectl apply. Follow the numbered examples below. Type each command, read the exact output, and match the meaning line before you move on. That is how real teams learn a tool.

Example 13: apply

Type this:

kubectl apply -f /tmp/k8s34/ing.yaml

You will see:

ingress.networking.k8s.io/shop-web created

What it means: Ingress object created.

Example 14: get

Type this:

kubectl get ingress shop-web

You will see:

NAME CLASS HOSTS ADDRESS PORTS
shop-web nginx shop.localtest.me ... 80

What it means: Host and class visible.

Example 15: desc

Type this:

kubectl describe ingress shop-web | head -20

You will see:

Name: shop-web
Address: ...
Rules: ...

What it means: Describe shows backend mapping.

Step 6: Hostname tips

Why: localtest.me hits 127.0.0.1. We do this before the next step so mistakes stay small and easy to undo. Read the output carefully; the numbers and names tell you if the machine is healthy.

What: hostname notes. Follow the numbered examples below. Type each command, read the exact output, and match the meaning line before you move on. That is how real teams learn a tool.

Example 16: why localtest

Type this:

echo 'localtest.me resolves to 127.0.0.1; useful for laptop Ingress demos'

You will see:

localtest.me resolves to 127.0.0.1; useful for laptop Ingress demos

What it means: Why this hostname works on a laptop.

Example 17: hosts tip

Type this:

echo 'Or add 127.0.0.1 shop.example.com to /etc/hosts on your machine'

You will see:

Or add 127.0.0.1 shop.example.com to /etc/hosts on your machine

What it means: Alternate hosts-file approach.

Example 18: no github

Type this:

echo 'Never paste random Ingress YAML from unknown blogs without reading every annotation'

You will see:

Never paste random Ingress YAML from unknown blogs without reading every annotation

What it means: Safety habit.

4. Automate and verify

Step 7: curl with Host

Why: Host header selects the rule. We do this before the next step so mistakes stay small and easy to undo. Read the output carefully; the numbers and names tell you if the machine is healthy.

What: curl -H Host. Follow the numbered examples below. Type each command, read the exact output, and match the meaning line before you move on. That is how real teams learn a tool.

Example 19: curl tip

Type this:

echo 'curl -H "Host: shop.localtest.me" http://127.0.0.1/'

You will see:

curl -H "Host: shop.localtest.me" http://127.0.0.1/

What it means: Host header test when nodePort or kind maps 80.

Example 20: kind ports

Type this:

echo 'kind maps host ports via extraPortMappings in the kind config for 80/443'

You will see:

kind maps host ports via extraPortMappings in the kind config for 80/443

What it means: kind port mapping tip.

Example 21: pf alt

Type this:

kubectl port-forward -n ingress-nginx svc/ingress-nginx-controller 8088:80 >/tmp/k8s34/pf.log 2>&1 & echo $!; sleep 1; curl -s -o /dev/null -w '%{http_code}' -H 'Host: shop.localtest.me' http://127.0.0.1:8088/

You will see:

What it means: Port-forward to controller returns 200 with Host header.

Step 8: Add /api path

Why: Second path shares the host. We do this before the next step so mistakes stay small and easy to undo. Read the output carefully; the numbers and names tell you if the machine is healthy.

What: second Ingress. Follow the numbered examples below. Type each command, read the exact output, and match the meaning line before you move on. That is how real teams learn a tool.

Example 22: second path

Type this:

printf '%s\n' 'apiVersion: networking.k8s.io/v1' 'kind: Ingress' 'metadata: {name: shop-api}' 'spec:' '  ingressClassName: nginx' '  rules:' '  - host: shop.localtest.me' '    http:' '      paths:' '      - path: /api' '        pathType: Prefix' '        backend:' '          service: {name: shop-web, port: {number: 80}}' > /tmp/k8s34/ing-api.yaml && kubectl apply -f /tmp/k8s34/ing-api.yaml

You will see:

ingress.networking.k8s.io/shop-api created

What it means: Second path /api on the same host.

Example 23: list

Type this:

kubectl get ingress

You will see:

NAME CLASS HOSTS
shop-web nginx shop.localtest.me
shop-api nginx shop.localtest.me

What it means: Both Ingress objects listed.

Example 24: paths

Type this:

kubectl get ingress shop-api -o jsonpath='{.spec.rules[0].http.paths[0].path}'; echo

You will see:

/api

What it means: Path stored as /api.

Step 9: Wrong vs right Host

Why: Wrong host gets 404. We do this before the next step so mistakes stay small and easy to undo. Read the output carefully; the numbers and names tell you if the machine is healthy.

What: compare Hosts. Follow the numbered examples below. Type each command, read the exact output, and match the meaning line before you move on. That is how real teams learn a tool.

Example 25: bad host

Type this:

curl -s -o /dev/null -w '%{http_code}' -H 'Host: wrong.example.com' http://127.0.0.1:8088/ || echo '000'

You will see:

What it means: Wrong Host header does not hit shop-web.

Example 26: good host

Type this:

curl -s -o /dev/null -w '%{http_code}' -H 'Host: shop.localtest.me' http://127.0.0.1:8088/

You will see:

What it means: Correct Host reaches the backend.

Example 27: stop pf

Type this:

pkill -f 'port-forward -n ingress-nginx' 2>/dev/null; echo stopped

You will see:

stopped

What it means: Controller forward stopped.

5. Harden and accept

Step 10: Events and IngressClass

Why: Describe for debugging. We do this before the next step so mistakes stay small and easy to undo. Read the output carefully; the numbers and names tell you if the machine is healthy.

What: kubectl get ingressclass. Follow the numbered examples below. Type each command, read the exact output, and match the meaning line before you move on. That is how real teams learn a tool.

Example 28: events

Type this:

kubectl get events --field-selector involvedObject.name=shop-web --sort-by=.lastTimestamp | tail -5

You will see:

... Scheduled ... Pulled ...

What it means: Recent events for debugging.

Example 29: class list

Type this:

kubectl get ingressclass

You will see:

NAME CONTROLLER
nginx k8s.io/ingress-nginx

What it means: IngressClass nginx is registered.

Example 30: anno tip

Type this:

echo 'Keep annotations minimal; every annotation is a footgun if copied blindly'

You will see:

Keep annotations minimal; every annotation is a footgun if copied blindly

What it means: Annotation habit.

Step 11: Cleanup extra Ingress

Why: Keep primary Ingress. We do this before the next step so mistakes stay small and easy to undo. Read the output carefully; the numbers and names tell you if the machine is healthy.

What: kubectl delete. Follow the numbered examples below. Type each command, read the exact output, and match the meaning line before you move on. That is how real teams learn a tool.

Example 31: delete api

Type this:

kubectl delete ingress shop-api --ignore-not-found

You will see:

ingress.networking.k8s.io "shop-api" deleted

What it means: Extra Ingress removed.

Example 32: keep web

Type this:

kubectl get ingress shop-web -o jsonpath='{.spec.rules[0].host}'; echo

You will see:

shop.localtest.me

What it means: Primary Ingress kept for HTTPS next.

Example 33: note

Type this:

echo 'Project 35 will add TLS on top of this Ingress'

You will see:

Project 35 will add TLS on top of this Ingress

What it means: Bridge to next project.

Step 12: Acceptance checklist

Why: Priya signs off. We do this before the next step so mistakes stay small and easy to undo. Read the output carefully; the numbers and names tell you if the machine is healthy.

What: All green. Follow the numbered examples below. Type each command, read the exact output, and match the meaning line before you move on. That is how real teams learn a tool.

Example 34: svc still

Type this:

kubectl get svc shop-web -o jsonpath='{.spec.type}'; echo

You will see:

ClusterIP

What it means: Backend still ClusterIP behind Ingress.

Example 35: deploy still

Type this:

kubectl get deploy shop-web -o jsonpath='{.status.readyReplicas}'; echo

You will see:

What it means: Replicas still Ready.

Example 36: Sign-off

Type this:

echo 'Priya: PASS'

You will see:

Priya: PASS

What it means: Project 34 accepted.

Check yourself

Q1. Who fixed Wipro demos?

Priya

Q2. Ingress class?

nginx

Q3. Demo host?

shop.localtest.me

Q4. Backend Service?

shop-web

Q5. Path?

Q6. Tool for Host test?

curl

Friends, you routed a hostname through Ingress to a Service. Did you understand? Let us try it once more. Add a second path /health on the same host.

Lab: try at home

Install ingress-nginx for kind.
Keep shop-web Service ready.
Apply Ingress with host rule.
Prove with Host header curl.
Clean extra paths.

Recap

Ingress needs a controller.
Rules match host and path.
Backend is a Service name.
Host header matters in tests.
TLS comes next with cert-manager.