When it comes to deploying your NestJS applications, understanding the various strategies can significantly enhance your app's performance, scalability, and maintainability. NestJS, built on top of Node.js, promotes a modern approach to backend development, and deploying these applications can be seamless with the right tools and methodologies. Let’s dive into some effective deployment strategies!

1. Containerization with Docker

Docker allows you to package your application along with its environment, making it easier to deploy consistently across various environments.

Why Use Docker?

• Consistent Environments: Ensure your application behaves the same in development, staging, and production.
• Scalability: Easily scale your application by running multiple containers.
• Isolation: Keep your app dependencies isolated, reducing potential conflicts.

Basic Steps to Dockerize a NestJS Application:

1. Install Docker: First, ensure you have Docker installed on your machine.

2. Create a Dockerfile: In the root of your NestJS project, create a Dockerfile with the following content:

   # Use the official Node.js image
   FROM node:14
   
   # Set the working directory
   WORKDIR /usr/src/app
   
   # Copy package.json and package-lock.json
   COPY package*.json ./
   
   # Install dependencies
   RUN npm install
   
   # Copy application code
   COPY . .
   
   # Expose the application's port
   EXPOSE 3000
   
   # Start the application
   CMD ["npm", "run", "start:prod"]

3. Build the Docker Image: Run the following command in your terminal:

   docker build -t my-nestjs-app .

4. Run the Docker Container: Use this command to run your container:

   docker run -p 3000:3000 my-nestjs-app

5. Access Your Application: Your app should now be running at http://localhost:3000.

2. Deploying on AWS EC2

AWS EC2 provides a flexible, scalable server environment where you can deploy your NestJS applications.

Setting Up AWS EC2:

1. Launch an EC2 Instance: Go to the AWS Management Console, launch an EC2 instance, and choose an Amazon Machine Image (AMI) like Ubuntu.

2. Connect to Your Instance: Use SSH to connect to your instance. For example:

   ssh -i "your-key.pem" ubuntu@your-ec2-instance-address

3. Install Node.js: Once logged in, install Node.js and npm:

   sudo apt update
   sudo apt install -y nodejs npm

4. Clone Your Application: Use Git to clone your NestJS app onto the server:

   git clone https://github.com/your-username/your-nestjs-repo.git
   cd your-nestjs-repo
   npm install --production

5. Run Your Application: Start your application using PM2 for process management, which keeps your app running:

   npm install -g pm2
   pm2 start dist/main.js --name my-nestjs-app

6. Configure Security Groups: Allow inbound traffic on the port your NestJS app runs (default is 3000).

7. Access Your Application: Visit http://YOUR_EC2_PUBLIC_IP:3000 to see your running app.

3. Using Heroku for Simple Deployments

Heroku is a cloud platform that enables developers to deploy applications simply and efficiently without managing the underlying infrastructure.

Deploying on Heroku:

1. Create a Heroku Account: Sign up and create a new app from the Heroku dashboard.

2. Install the Heroku CLI: Make sure to install the Heroku Command Line Interface.

3. Login to Heroku: Authenticate via the command line:

   heroku login

4. Prepare Your App: Ensure you have a Procfile in the root of your project. This file tells Heroku how to run your application:

   web: npm run start:prod

5. Deploy Your Application: Deploy using Git:

   git init
   heroku git:remote -a your-heroku-app-name
   git add .
   git commit -m "Initial commit"
   git push heroku master

6. Scale Your Dynos: By default, your app will run on a single dyno. Scale vertically or horizontally as needed:

   heroku ps:scale web=1

7. Access Your Application: Navigate to https://your-heroku-app-name.herokuapp.com to see your app live.

4. Using Serverless Frameworks

Serverless architecture can be beneficial for deploying specific functionalities. You might use services like AWS Lambda to run your NestJS functions without managing servers.

Deploying with Serverless:

1. Install Serverless Framework:

   npm install -g serverless

2. Create a Serverless Project:

   serverless create --template aws-nodejs --path my-nestjs-serverless
   cd my-nestjs-serverless

3. Add Your NestJS Code: Integrate your NestJS code into the project, focusing on creating handlers for functions.

4. Deploy Your Functions: Deploy your application:

   serverless deploy

5. Test Your Endpoint: Get the endpoint URL generated by AWS to test your deployed function.

Conclusion

With these deployment strategies at your disposal, you can choose the most appropriate method for your NestJS application based on needs and resources. Each strategy provides unique advantages and serves different use cases, enabling you to deliver robust applications effectively. Remember, it's not just about deploying, but about how well your app can perform and scale in production environments. Explore and experiment with these methods to find the best fit for your application!