Article 19: Kubernetes Basics for Microservices

1. Objective

Understand Kubernetes fundamentals and how it runs microservices at scale.

2. Key Concepts

• Kubernetes (K8s)
• Pod
• Deployment
• Service
• ConfigMap
• Scaling

3. Why Kubernetes?

Problems Docker Compose cannot solve:

• Auto-scaling
• Self-healing
• Rolling updates
• Production orchestration

4. Kubernetes Architecture (High Level)

[Client]
   |
[Kubernetes Service]
   |
[Pods] -> Containers

5. Core Components Explained

• Pod: Smallest deployable unit
• Deployment: Manages replicas
• Service: Stable network endpoint

6. Sample Deployment YAML

apiVersion: apps/v1
kind: Deployment
metadata:
  name: user-service
spec:
  replicas: 2
  selector:
    matchLabels:
      app: user-service
  template:
    metadata:
      labels:
        app: user-service
    spec:
      containers:
        - name: user-service
          image: user-service:latest
          ports:
            - containerPort: 8081

7. Service YAML

apiVersion: v1
kind: Service
metadata:
  name: user-service
spec:
  selector:
    app: user-service
  ports:
    - port: 80
      targetPort: 8081

8. Common Mistakes

• Treating pods as servers
• Hardcoding configs
• Skipping readiness probes

9. Interview Notes

• Kubernetes provides self-healing and scaling
• Services provide stable networking

10. Summary

Kubernetes is the standard platform for running microservices.

11. What’s Next

Build an end-to-end microservices project.