Deploying TypeScript on Kubernetes: A Basic Guide

Deploying TypeScript on Kubernetes: Basic Guide

Modern web development increasingly requires not only writing quality code, but also competent application deployment. TypeScript, thanks to strict typing and powerful tools, has become a popular choice for backend services on Node.js. However, without proper deployment, even perfect code will remain on the local machine. Kubernetes — the container orchestration standard — allows you to automate deployment, scaling, and management of applications. In this guide, we'll walk through the step-by-step process of deploying a TypeScript application on Kubernetes.

1. Preparing the TypeScript Application for Containerization

Before sending code to the cluster, you need to ensure the application is ready to work in a container. Let's look at a typical Express.js project with TypeScript.

Project Structure

my-ts-app/├── src/│   ├── index.ts│   └── routes/├── dist/├── package.json├── tsconfig.json└── Dockerfile

Configuring tsconfig.json

Make sure the TypeScript compiler builds the project into the dist folder:

{  "compilerOptions": {    "target": "ES2020",    "module": "commonjs",    "outDir": "./dist",    "rootDir": "./src",    "strict": true,    "esModuleInterop": true  },  "include": ["src/**/*"]}

Simple Server (src/index.ts)

import express, { Request, Response } from 'express';

const app = express();const PORT = process.env.PORT || 3000;

app.get('/health', (_req: Request, res: Response) => {  res.json({ status: 'ok', timestamp: new Date().toISOString() });});

app.listen(PORT, () => {  console.log(`Server running on port ${PORT}`);});

Add scripts to package.json:

"scripts": {  "build": "tsc",  "start": "node dist/index.js",  "dev": "ts-node src/index.ts"}

2. Building a Docker Image for TypeScript

Containerization is a key step before deploying to Kubernetes. We use multi-stage build to reduce the image size.

Dockerfile

# Stage 1: BuildFROM node:18-alpine AS builderWORKDIR /appCOPY package*.json ./RUN npm ciCOPY tsconfig.json ./COPY src/ ./src/RUN npm run build

# Stage 2: ProductionFROM node:18-alpine AS productionWORKDIR /appCOPY --from=builder /app/dist ./distCOPY --from=builder /app/package*.json ./RUN npm ci --only=productionEXPOSE 3000CMD ["node", "dist/index.js"]

Build the image and push it to a registry (e.g., Docker Hub):

docker build -t yourusername/my-ts-app:v1 .docker push yourusername/my-ts-app:v1

3. Writing Kubernetes Manifests

For deployment in Kubernetes, you'll need at least two resources: Deployment (pod management) and Service (application access).

deployment.yaml

apiVersion: apps/v1kind: Deploymentmetadata:  name: my-ts-app  labels:    app: my-ts-appspec:  replicas: 2  selector:    matchLabels:      app: my-ts-app  template:    metadata:      labels:        app: my-ts-app    spec:      containers:      - name: app        image: yourusername/my-ts-app:v1        ports:        - containerPort: 3000        env:        - name: PORT          value: "3000"        livenessProbe:          httpGet:            path: /health            port: 3000          initialDelaySeconds: 5          periodSeconds: 10        readinessProbe:          httpGet:            path: /health            port: 3000          initialDelaySeconds: 3          periodSeconds: 5

service.yaml

apiVersion: v1kind: Servicemetadata:  name: my-ts-app-servicespec:  selector:    app: my-ts-app  ports:  - protocol: T