1. Core Concepts

• Pods: Smallest deployable unit in Kubernetes, encapsulating containers.
• ReplicaSets: Ensures specified number of pod replicas are running.
• Deployments: Declarative updates for Pods and ReplicaSets.
• Services: Expose your app as ClusterIP, NodePort or LoadBalancer.
• Namespaces: Logical partitions of cluster resources.

2. Sample YAML Deployment

apiVersion: apps/v1
kind: Deployment
metadata:
  name: my-app
spec:
  replicas: 3
  selector:
    matchLabels:
      app: my-app
  template:
    metadata:
      labels:
        app: my-app
    spec:
      containers:
      - name: my-app-container
        image: my-app-image:latest
        ports:
        - containerPort: 8080
        readinessProbe:
          httpGet:
            path: /healthz
            port: 8080
          initialDelaySeconds: 5
          periodSeconds: 10
      

3. ConfigMaps & Secrets

• Use ConfigMap to store non-sensitive configuration data.
• Use Secret for sensitive data like passwords, API keys.

4. Services & Networking

• ClusterIP: Default service type, reachable only within cluster.
• NodePort: Exposes service on each node's port.
• LoadBalancer: Creates external load balancer for service access.

5. Helm Charts

• Package Kubernetes applications with Helm for easy deployment and versioning.
• Define values.yaml for configurable templates.

6. CI/CD Integration

• Automate deployments using Jenkins, GitHub Actions or GitLab CI/CD.
• Scan images using Trivy or Snyk for vulnerabilities before deploying.
• Use ArgoCD or FluxCD for GitOps-style continuous deployment.