Three-Tier Architecture on a Budget: Using AWS Free Tier Effectively
Introduction
Building a scalable, three-tier architecture on AWS doesn’t have to be expensive. By leveraging Amazon S3 for static assets, AWS Lambda for backend processing, and DynamoDB for database storage, you can create a cost-effective architecture that meets the needs of small applications. To further reduce costs, creating a separate AWS account for each application allows you to maximize AWS’s free tier offerings across multiple applications. This article will guide you through setting up a three-tier architecture on a budget.
Architecture Overview
Presentation Tier: Amazon S3 serves as the frontend layer, hosting static assets such as HTML, CSS, and JavaScript.
Application Tier: AWS Lambda functions handle backend logic, responding to API requests and processing data.
Data Tier: Amazon DynamoDB provides fast, scalable NoSQL storage for application data.
Using these services not only simplifies setup and scaling but also takes advantage of the free tier to keep costs down.
Step 1: Set Up the Presentation Tier with Amazon S3
Amazon S3 is ideal for hosting static assets like HTML, CSS, JavaScript, and images, making it a great choice for the presentation tier.
Create an S3 Bucket:
Go to the S3 Console and create a new bucket with a unique name (e.g., my-app-frontend).
Enable Static Website Hosting:
Under the bucket’s Properties tab, enable Static website hosting.
Specify an index document (e.g., index.html) and error document if needed.
Upload Static Files:
Upload your static assets to the S3 bucket.
Set Bucket Policy for Public Access (if needed):
Configure the bucket policy to allow public read access to the static files.
Free Tier Benefit:
The AWS free tier offers 5 GB of standard storage per month, 20,000 GET requests, and 2,000 PUT requests for S3.
Step 2: Set Up the Application Tier with AWS Lambda
AWS Lambda allows you to run backend logic without managing servers, making it a cost-effective solution for the application tier.
Create a Lambda Function:
Go to the Lambda Console and create a new function. Choose “Author from scratch,” give it a name (e.g., my-app-backend), and select a runtime (e.g., Node.js or Python).
Write Backend Logic:
Write the backend code for your Lambda function. This code will process incoming requests and interact with DynamoDB.
Set Up API Gateway (Optional):
If your application requires API endpoints, create an API Gateway and integrate it with your Lambda function. This setup allows frontend requests to be routed to your backend.
Free Tier Benefit:
AWS Lambda offers 1 million free requests and 400,000 GB-seconds of compute time per month under the free tier.
Step 3: Set Up the Data Tier with Amazon DynamoDB
Amazon DynamoDB is a fully managed NoSQL database that scales automatically, providing a cost-effective data storage solution.
Create a DynamoDB Table:
Go to the DynamoDB Console and create a new table. Define a primary key, such as userId for a user-based application.
Configure Read/Write Capacity:
Use the on-demand capacity mode for low traffic to save costs, especially if you’re still within the free tier limits.
Connect Lambda to DynamoDB:
In your Lambda function, use the AWS SDK to interact with DynamoDB. For example, you can create, read, update, and delete items from the DynamoDB table.
Free Tier Benefit:
DynamoDB’s free tier includes 25 GB of storage, 25 read capacity units, and 25 write capacity units per month.
Extra Cost-Saving Tip: Use Multiple AWS Accounts for Free Tier Benefits
AWS’s free tier is available per account, so creating separate accounts for each application can extend free-tier usage. Here’s how:
Set Up Separate Accounts:
Create a new AWS account for each application you want to deploy. This approach resets the free tier for each account, allowing each application to maximize the free-tier benefits.
Link Accounts with AWS Organizations (Optional):
If managing multiple accounts, use AWS Organizations to consolidate billing and simplify account management.
Important Considerations:
Be mindful of AWS’s free tier limits to avoid unexpected charges.
Monitor each account’s usage regularly using AWS Budgets to keep costs under control.
Example Workflow: Putting It All Together
Here’s an example workflow for a simple application using this architecture:
Frontend Request: A user visits your website, and the static assets are served from S3.
API Call to Lambda: The frontend makes an API call to a Lambda function through API Gateway.
Data Interaction with DynamoDB: Lambda processes the request, interacting with DynamoDB to fetch or update data.
Response to Frontend: The Lambda function returns data to the frontend, and the user sees the updated information.
Conclusion
With AWS’s free tier offerings and a smart design, you can create a cost-effective three-tier architecture that’s scalable and secure. By using S3 for static assets, Lambda for backend processing, and DynamoDB for data storage, you reduce infrastructure costs while still providing a robust application setup. Additionally, setting up separate accounts for each application maximizes the free tier benefits, making this approach ideal for small to medium-sized applications on a budget.