Kubernetes — Complete Guide

Kubernetes — Complete Guide: free step-by-step lesson with examples, common mistakes, and interview tips — part of React.js Tutorial on Toolliyo Academy.

8 min read Updated 7/8/2026

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React.js Tutorial · Lesson 88 of 100

Kubernetes

Beginner ✓ → Intermediate ✓ → Advanced ✓ → Professional

Professional · 4 — ShopCart projects · ~25 min read · Module 9: Testing & Deployment

Introduction

Professional project lesson: Kubernetes. You will put together routing, data, and UI like a portfolio app. Build one piece at a time — do not rush. Kubernetes (K8s) runs and scales containerized apps across clusters — deploy React nginx containers, load balance, roll out updates. Large orgs run dozens of services. K8s handles replicas, health checks, and zero-downtime deploys.

A app on your laptop is not finished until it runs somewhere others can open a URL.

When will you use this?

Use when you are ready to put the app online for users or employers to see.

Shipping means tests pass, build succeeds, and Docker or Azure hosts the static files.
Companies run CI so broken code never reaches users.

Real-world: three React nginx replicas

K8s Deployment runs 3 pods serving React static files behind Ingress — rolling update with zero downtime.

Production-style code

# deployment.yaml (excerpt)
spec:
  replicas: 3
  template:
    spec:
      containers:
        - name: web
          image: toolliyo/react-spa:1.4.2
          ports:
            - containerPort: 80
          resources:
            requests:
              memory: "64Mi"
              cpu: "50m"

What happens in production: Horizontal scale for frontend static servers — health checks restart crashed pods automatically.

Lesson example (start here)

Copy this smaller example first. Once it works, compare it with the real-world code above.

# deployment.yaml snippet
spec:
  replicas: 3
  template:
    spec:
      containers:
      - name: web
        image: myregistry/react-app:1.0.0
        ports:
        - containerPort: 80

Line-by-line walkthrough

Code	What it means
`# deployment.yaml snippet`	Comment — notes for humans; the computer ignores it.
`spec:`	Part of the Kubernetes example — read it together with the lines before and after.
`replicas: 3`	Part of the Kubernetes example — read it together with the lines before and after.
`template:`	Part of the Kubernetes example — read it together with the lines before and after.
`spec:`	Part of the Kubernetes example — read it together with the lines before and after.
`containers:`	Part of the Kubernetes example — read it together with the lines before and after.
`- name: web`	Part of the Kubernetes example — read it together with the lines before and after.
`image: myregistry/react-app:1.0.0`	Part of the Kubernetes example — read it together with the lines before and after.
`ports:`	Part of the Kubernetes example — read it together with the lines before and after.
`- containerPort: 80`	Part of the Kubernetes example — read it together with the lines before and after.

How it works (big picture)

Deployment defines pod template and replica count.
Service exposes pods to traffic.
Ingress routes HTTPS domain.

Do this on your computer

Containerize React app first.
Learn kubectl apply -f deployment.yaml.
Use managed K8s (AKS, EKS) before self-hosting.
Read the real-world section and name which part of the app uses this topic.
Run the example locally and confirm the same behavior in the browser.
Change one value in the example (text, initial state, or URL) and predict what will happen before you save.

Experiments — try changing this

Change text or labels in the example and save — watch the browser update.
Break the code on purpose (remove a bracket), read the error message, then fix it.

Remember

K8s orchestrates containers at scale. Learn Docker first. Use when team needs auto-scale and many services.

Common questions

Static React on K8s?

Common pattern: nginx container + Deployment + Ingress.

How long should I spend on Kubernetes?

Until you can explain it in your own words and run the example without looking at the answer. Beginners often need 30–60 minutes per new hook or routing topic; setup lessons may take one afternoon.

What if I get stuck on Kubernetes?

Re-read the line-by-line walkthrough, check the browser console for red errors, and compare your code character-by-character with the example. Search the exact error text — someone else had it too.

Where is Kubernetes used in real jobs?

See the real-world section above — the same pattern appears in LMS, banking, e-commerce, and SaaS products. Interviewers ask you to explain it using one concrete example from your project or this lesson.

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