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DevOps Roadmap — Part 9: Kubernetes Basics

Agar Docker containers factory me bante hain, toh Kubernetes unka manager hai. Real DevOps yahin se large-scale hota hai.

Why Kubernetes Exists

Docker sirf container chalata hai. Par production me problems aati hain:

• 100+ containers kaise manage kare?
• Container crash ho jaye toh?
• Traffic badhe toh scaling kaise ho?

Iska answer hai: Kubernetes (K8s)

What Is Kubernetes?

Kubernetes ek container orchestration system hai jo:

• Containers deploy karta hai
• Automatically restart karta hai
• Load balance karta hai
• Auto-scale karta hai

Google ne banaya, industry ne adopt kiya.

Kubernetes Architecture (Simple)

• Cluster – complete system
• Node – ek machine (VM/server)
• Pod – smallest unit

👉 Container directly nahi, pod ke andar chalta hai.

What Is a Pod?

Pod ek wrapper hai jo:

• 1 ya multiple containers rakhta hai
• Same network share karta hai
• Same storage use karta hai

Production me rarely single container pods.

Basic Kubernetes Objects

• Pod – container holder
• Deployment – desired state maintain karta hai
• Service – networking & access

Deployment Explained

Deployment batata hai:

• Kitne pods chahiye
• Konsa image use hoga
• Restart policy

apiVersion: apps/v1
kind: Deployment
metadata:
  name: web-app
spec:
  replicas: 3
  selector:
    matchLabels:
      app: web
  template:
    metadata:
      labels:
        app: web
    spec:
      containers:
      - name: web
        image: nginx

Yeh ensure karta hai: 3 pods always running.

What Is a Service?

Pods ka IP dynamic hota hai. Service ek stable endpoint provide karta hai.

• ClusterIP – internal
• NodePort – external basic
• LoadBalancer – cloud level

kubectl — Kubernetes Command Tool

kubectl get pods
kubectl get nodes
kubectl apply -f app.yaml
kubectl delete pod pod-name

kubectl = Kubernetes ka remote control.

Why Kubernetes Is Hard for Beginners

• Too many concepts
• YAML heavy
• Networking complex

Isliye pehle Docker + CI/CD samajhna zaruri tha.

Reality Check

DevOps engineers:

• Pods create nahi karte daily
• Issues troubleshoot karte hain
• Scaling & upgrades handle karte hain

Understanding > memorizing.

What Comes Next?

Ab containers production me chal rahe hain. Next step: Cloud platforms (AWS/GCP/Azure)