Tutorial - Distribuire la tua prima applicazione

Obiettivi

Questo tutorial ti guida passo dopo passo per eseguire il tuo primo deployment su un cluster Managed Kubernetes. Al termine di questa guida, avrai:

Distribuito un'applicazione web semplice.
Reso accessibile questa applicazione all'interno del cluster tramite un Service.
Reso l'applicazione raggiungibile da Internet tramite un Ingress.

Prerequisiti

Hai configurato l'accesso al cluster come descritto nella guida introduttiva.
Disponi di uno spazio dei nomi su cui hai i permessi di distribuzione. In questo tutorial utilizzeremo uno spazio dei nomi denominato hello-world.

Step 1: Create a namespace

If not already done, create a namespace to isolate your application.

kubectl create namespace hello-world

Passo 2: Distribuire un'applicazione "Hello World"

Distribuiremo un'applicazione dimostrativa che visualizza una semplice pagina web.

Crea un file denominato deployment.yaml con il seguente contenuto:

apiVersion: apps/v1
kind: Deployment
metadata:
  name: hello-world-deployment
  namespace: hello-world
  labels:
    app: hello-world
spec:
  replicas: 2
  selector:
    matchLabels:
      app: hello-world
  template:
    metadata:
      labels:
        app: hello-world
    spec:
      containers:
      - name: hello-world
        image: nginxdemos/hello:plain-text
        ports:
        - containerPort: 80

Applica questo manifesto al tuo cluster:
```
kubectl apply -f deployment.yaml
```

Verifica che il deployment sia stato creato e che i pod siano in esecuzione:

kubectl get deployment -n hello-world
# Dovresti vedere il tuo deployment con 2/2 replica pronte.
NAME                     READY   UP-TO-DATE   AVAILABLE   AGE
hello-world-deployment   2/2     2            2           102s

kubectl get pods -n hello-world
# Dovresti vedere due pod con lo stato "Running".
NAME                                      READY   STATUS    RESTARTS   AGE
hello-world-deployment-669dfbd799-294zz   1/1     Running   0          2m21s
hello-world-deployment-669dfbd799-plcbg   1/1     Running   0          2m21s

Step 3: Expose the application in the cluster (Service)

To allow different components of the cluster to communicate with our application, we need to create a Service.

Create a file named service.yaml:

apiVersion: v1
kind: Service
metadata:
  name: hello-world-service
  namespace: hello-world
spec:
  selector:
    app: hello-world
  ports:
    - protocol: TCP
      port: 80
      targetPort: 80
  type: ClusterIP

Apply the manifest:
```
kubectl apply -f service.yaml
```
Your application is now accessible via the name hello-world-service.hello-world from any other pod in the cluster.

Step 4: Make the application accessible from the internet (Ingress)

To expose our service on the internet, we will use an Ingress resource. The Managed Kubernetes offering provides several preconfigured ingressClassName values. We will use nginx-external for public exposure.

Create a file named ingress.yaml. Remember to replace your-cluster-id with your cluster's identifier (e.g., ctodev).

apiVersion: networking.k8s.io/v1
kind: Ingress
metadata:
  name: hello-world-ingress
  namespace: hello-world
spec:
  ingressClassName: nginx-external
  rules:
  - host: "hello-world.external.your-cluster-id.mk.ms-cloud-temple.com" # change me
    http:
      paths:
      - path: /
        pathType: Prefix
        backend:
          service:
            name: hello-world-service
            port:
              number: 80

Apply the manifest:
```
kubectl apply -f ingress.yaml
```

Step 5: Verify Access

An DNS entry "*" is already pointing all URLs ending with ".external.votre-cluster-id.mk.ms-cloud-temple.com" to the IP address of the "external" ingress.
Applications published under this DNS suffix are therefore directly accessible.

curl http://hello-world.external.votre-cluster-id.mk.ms-cloud-temple.com

You should receive a response from the demo NGINX server.

StatusCode        : 200
StatusDescription : OK
Content           : Server address: 10.247.1.223:80
                    Server name: hello-world-deployment-669dfbd799-plcbg
                    Date: 29/Oct/2025:15:40:04 +0000
                    URI: /
                    Request ID: 2df985e0630c3a123b5cde23b687a033

RawContent        : HTTP/1.1 200 OK
                    Connection: keep-alive
                    Content-Length: 170
                    Cache-Control: no-cache
                    Content-Type: text/plain
                    Date: Wed, 29 Oct 2025 15:40:04 GMT
                    Expires: Wed, 29 Oct 2025 15:40:03 GMT
                    Server: ng...

Going further: Security in production

This tutorial has shown you the basics of deployment. For a production environment, it is crucial to apply additional security measures:

Use secure images: Prefer images from your enterprise secure registry such as Harbor, rather than public images.
Control network traffic: Implement NetworkPolicies to restrict communications to only the necessary flows between your applications.
Apply governance policies: Use tools like Kyverno to enforce security rules (e.g., prohibit "root" containers, require resource requests and limits, etc.).

Pulizia

Per eliminare tutte le risorse create durante questa guida, è sufficiente eliminare lo spazio dei nomi:

kubectl delete namespace hello-world

Congratulazioni, hai distribuito ed esposto la tua prima applicazione su Managed Kubernetes!

Obiettivi​

Prerequisiti​

Step 1: Create a namespace​

Passo 2: Distribuire un'applicazione "Hello World"​

Step 3: Expose the application in the cluster (Service)​

Step 4: Make the application accessible from the internet (Ingress)​

Step 5: Verify Access​

Pulizia​