What actions did you perform to launch applications or services in the Kubernetes cluster?

To deploy applications or services in a Kubernetes cluster, I usually perform the following steps:

1. Create YAML manifest files describing the necessary Kubernetes objects such as Deployment, Service, ConfigMap, etc.
2. Define containers with the application image, specify the number of replicas, resources, and environment variables.
3. Apply the manifests using the command kubectl apply -f <file.yaml> to create or update resources in the cluster.
4. Check the status of running pods and services using kubectl get pods, kubectl get services.
5. If necessary, configure Ingress for external access to the services.

An example of a simple Deployment for a Python application:

apiVersion: apps/v1
kind: Deployment
metadata:
  name: python-app
spec:
  replicas: 3
  selector:
    matchLabels:
      app: python-app
  template:
    metadata:
      labels:
        app: python-app
    spec:
      containers:
      - name: python-container
        image: python:3.9-slim
        command: ["python", "-m", "http.server", "8000"]
        ports:
        - containerPort: 8000

Then run:

kubectl apply -f deployment.yaml
kubectl expose deployment python-app --type=NodePort --port=8000