How to Deploy Serverless Applications on AWS Using Docker and Terraform

The rise of cloud computing has revolutionized how we develop and deploy applications. Among the most popular cloud providers, Amazon Web Services (AWS) stands out with its serverless architecture, allowing developers to focus on writing code without worrying about infrastructure management. In this guide, we’ll explore how to deploy a serverless application on AWS using Docker containers and Terraform as our infrastructure-as-code tool.

What is Serverless Computing?

Serverless computing allows developers to build and run applications without managing servers. The term "serverless" doesn’t mean there are no servers; rather, it abstracts the underlying infrastructure, allowing developers to focus on writing code. AWS Lambda is a prime example of serverless technology, enabling code execution in response to events.

Benefits of Serverless Architecture

• Cost Efficiency: Pay only for the compute time you consume.
• Scalability: Automatically scales with the application's needs.
• Reduced Operational Overhead: No server maintenance is required.

Why Use Docker with AWS Lambda?

Docker allows you to package your application and its dependencies into a single container, ensuring consistency across different environments. With AWS Lambda’s support for container images, you can leverage Docker to deploy your serverless applications more efficiently.

Use Cases

• Microservices Architecture: Deploy individual services independently.
• Batch Processing: Run jobs triggered by events without managing servers.
• APIs: Create scalable RESTful APIs without worrying about infrastructure.

Getting Started: Prerequisites

Before we dive into the deployment process, ensure you have the following: - An AWS account - Docker installed on your local machine - Terraform installed on your local machine - AWS CLI configured with appropriate permissions

Step 1: Create a Simple Node.js Application

Let’s create a simple Node.js application that returns a “Hello, World!” message.

1. Create a project directory: bash mkdir serverless-docker-app cd serverless-docker-app

2. Create an index.js file: ```javascript const response = { statusCode: 200, body: JSON.stringify( { message: 'Hello, World!', }, null, 2 ), };

exports.handler = async (event) => { return response; }; ```

1. Create a package.json file: json { "name": "serverless-docker-app", "version": "1.0.0", "main": "index.js", "scripts": { "start": "node index.js" }, "dependencies": {} }

Step 2: Create a Dockerfile

Next, we need a Dockerfile to containerize our application.

1. Create a Dockerfile: ```Dockerfile FROM public.ecr.aws/lambda/nodejs:14

COPY package.json ./ RUN npm install COPY index.js ./

CMD ["index.handler"] ```

This Dockerfile uses the AWS Lambda Node.js base image, installs dependencies, and sets the command to run the Lambda function.

Step 3: Build and Test the Docker Image

1. Build the Docker image: bash docker build -t serverless-docker-app .

2. Run the Docker container locally: bash docker run -p 9000:8080 serverless-docker-app

3. Test the function: Open another terminal and execute: bash curl http://localhost:9000/2015-03-31/functions/function/invocations

You should receive the response:

{
  "message": "Hello, World!"
}

Step 4: Deploy with Terraform

Now that we have our Docker container ready, let’s deploy it to AWS Lambda using Terraform.

1. Create a main.tf file: ```hcl provider "aws" { region = "us-east-1" }

resource "aws_lambda_function" "example" { function_name = "serverless-docker-app" image_uri = "your_account_id.dkr.ecr.us-east-1.amazonaws.com/serverless-docker-app:latest" package_type = "Image"

 role = aws_iam_role.lambda_role.arn

}

resource "aws_iam_role" "lambda_role" { name = "lambda_exec_role"

 assume_role_policy = jsonencode({
   Version = "2012-10-17"
   Statement = [{
     Action = "sts:AssumeRole"
     Principal = {
       Service = "lambda.amazonaws.com"
     }
     Effect = "Allow"
     Sid    = ""
   }]
 })

} ```

1. Initialize Terraform: bash terraform init

2. Build and Push the Docker Image to ECR:

3. Authenticate Docker to your ECR: bash aws ecr get-login-password --region us-east-1 | docker login --username AWS --password-stdin your_account_id.dkr.ecr.us-east-1.amazonaws.com

4. Create a repository: bash aws ecr create-repository --repository-name serverless-docker-app

5. Tag and push the image: bash docker tag serverless-docker-app:latest your_account_id.dkr.ecr.us-east-1.amazonaws.com/serverless-docker-app:latest docker push your_account_id.dkr.ecr.us-east-1.amazonaws.com/serverless-docker-app:latest

6. Deploy the Lambda function: bash terraform apply

Step 5: Invoke the Lambda Function

Finally, you can invoke your deployed Lambda function through the AWS Management Console or using the AWS CLI:

aws lambda invoke --function-name serverless-docker-app output.txt

Conclusion

Deploying serverless applications on AWS using Docker and Terraform streamlines the development process, allowing for rapid iterations and scaling. By leveraging the power of containers and infrastructure-as-code, developers can manage deployments more efficiently while minimizing operational overhead. With this guide, you’re now equipped to build, package, and deploy your own serverless applications on AWS. Happy coding!