Three Tier Architecture on AWS using Terraform

 Three Tier Architecture:

A three-tier architecture, also known as a multi-tier architecture, is a design pattern commonly used in software and web application development to separate different components of an application into distinct layers. Each layer has a specific role and interacts with the other layers through well-defined interfaces. This architecture promotes modularity, scalability, and ease of maintenance.

Presentation Tier (Web Tier):

This is the top layer that interacts directly with users or clients. It handles user interface (UI) rendering and user interactions. In web applications, the presentation tier often includes components like web servers, load balancers, and content delivery networks (CDNs). On AWS, the presentation tier might involve resources like Amazon Elastic Load Balancer (ELB), Amazon CloudFront (CDN), and Amazon Route 53 (DNS service). These resources help distribute user requests and deliver content efficiently.

Application Tier (Logic Tier):

The middle layer of the architecture contains the application's business logic and processing. It handles the application's functionality and processes user inputs from the presentation tier. This tier can include application servers, microservices, and APIs. AWS offers various services for the application tier, such as Amazon EC2 (Elastic Compute Cloud) for virtual servers, Amazon ECS (Elastic Container Service) for containerized applications, and AWS Lambda for serverless functions.

Data Tier (Data Storage Tier):

The bottom layer is responsible for managing and storing data used by the application. It includes databases, data storage, and data processing components. The data tier ensures data persistence and integrity. AWS provides several database services for the data tier, including Amazon RDS (Relational Database Service) for relational databases, Amazon DynamoDB for NoSQL databases, and Amazon S3 (Simple Storage Service) for object storage.

                                                                        FIG. ARCHITECTURE DIAGRAM

Tier 1: Presentation Tier (Web Tier):

1. Create a Virtual Private Cloud (VPC):

• Go to the AWS Management Console.
• Navigate to the VPC dashboard and create a new VPC.
• Define subnets for public access (for the presentation tier) and private access (for the application and database tiers).

1. Launch a Load Balancer:

• Create an Application Load Balancer (ALB) or Network Load Balancer (NLB) in the public subnet.
• Configure the load balancer to distribute traffic to instances in the application tier.

Set Up Security Groups:

• Create security groups for the load balancer and the presentation tier instances.
• Configure inbound rules to allow HTTP/HTTPS traffic.

Tier 2: Application Tier (Logic Tier):

1. Launch EC2 Instances:

• Launch EC2 instances in the private subnet of the VPC for your application tier.
• Install necessary software, frameworks, and code on these instances.

1. Configure Auto Scaling:

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   • Set up Auto Scaling groups for the application instances to automatically adjust capacity based on demand.
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2. Implement Security Groups:

• Create security groups for the application instances.
• Configure inbound rules to allow traffic from the load balancer and other necessary sources.

1. Tier 3: Data Tier (Data Storage Tier):

   1. Choose a Database Service:

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      • Select an appropriate AWS database service based on your application's requirements (Amazon RDS for relational databases, Amazon DynamoDB for NoSQL, etc.).

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   3. Set Up the Database:

   • Create a database instance in the private subnet of the VPC.
   • Configure security groups to control access to the database.

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3. Implement Data Management:

• Configure database schema, tables, and indexes as needed.
• Implement data access logic in the application tier to interact with the database.

Networking and Security:

1. Networking Configuration:

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   • Set up VPC peering, transit gateways, or other networking solutions to ensure communication between tiers while maintaining security boundaries.

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3. Access Control:

• Use IAM roles and policies to control access to AWS resources.
• Implement security best practices, such as least privilege and role separation.

1. SSL Certificates:

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• Obtain and configure SSL certificates for secure communication between users and the presentation tier.
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Testing and Deployment:

1. Testing:

• Test the architecture thoroughly to ensure proper functionality and performance.
• Use tools like AWS CloudWatch for monitoring and debugging.

1. Deployment:

• Implement a deployment strategy for updating application code and configuration.
• Consider using AWS CodeDeploy or other deployment tools.

Advantages:

1. Scalability: Each tier can be scaled independently to handle varying loads. This ensures efficient resource utilization and responsiveness.

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3. Modularity: Separating concerns into different tiers makes the application easier to develop, test, and maintain.

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5. Security: Segregating components enhances security by limiting access between tiers. AWS's security features can be leveraged to further protect each tier.

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7. Flexibility: Different tiers can use different technologies and languages as long as they adhere to the specified interfaces.

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9. High Availability: AWS provides tools like load balancers and auto-scaling groups that enhance application availability and fault tolerance.

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11. Performance: By distributing components across multiple tiers, bottlenecks can be minimized, leading to improved performance.

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• Conclusion:
• Summarize the key points covered in the blog post. Reinforce the benefits of using a three-tier architecture on AWS with Terraform. Encourage readers to explore further resources, AWS documentation, and Terraform's official guides.