45 ‐ 3 Tier Architecture - SanjeevOCI/Ocidocs GitHub Wiki

                     ┌──────────────────────────────┐
                     │         Internet             │
                     └──────────────▲──────────────┘
                                    │
                     ┌──────────────▼──────────────┐
                     │      OCI Load Balancer      │  (Public Subnet)
                     └──────────────▲──────────────┘
                                    │
                ┌───────────────────┴───────────────────┐
                │                                       │
      ┌────────▼────────┐                     ┌────────▼────────┐
      │  Web Server 1   │                     │  Web Server 2   │  (Public Subnet)
      └────────────────┘                     └────────────────┘
                │                                       │
                └───────────────┬───────────────┘
                                │
                    ┌───────────▼───────────┐
                    │  Application Servers  │  (Private Subnet)
                    └───────────▲───────────┘
                                │
                    ┌───────────▼───────────┐
                    │  Oracle Database      │  (Private Subnet)
                    └───────────────────────┘

A 3-tier architecture is a well-established software architecture pattern that separates an application into three logical layers: the presentation layer, the application layer, and the data layer. In Oracle Cloud Infrastructure (OCI), you can implement a 3-tier architecture using various OCI services.

Components of a 3-Tier Architecture in OCI

1. Presentation Layer (Web Tier):

   • This layer is responsible for the user interface and user interaction.
   • Typically consists of web servers or load balancers.
   • In OCI, you can use:
     • OCI Load Balancer: To distribute incoming traffic across multiple web servers.
     • Compute Instances: Running web server software (e.g., Apache, Nginx).

2. Application Layer (App Tier):

   • This layer contains the business logic and application processing.
   • Typically consists of application servers.
   • In OCI, you can use:
     • Compute Instances: Running application server software (e.g., Java EE, Node.js, Python).
     • OCI Container Engine for Kubernetes (OKE): To deploy and manage containerized applications.

3. Data Layer (Database Tier):

   • This layer is responsible for data storage and management.
   • Typically consists of database servers.
   • In OCI, you can use:
     • OCI Autonomous Database: For a fully managed database service.
     • OCI Database: For more control over database management.
     • OCI Object Storage: For storing unstructured data.

Example Architecture Diagram

Here is an example of how we can set up a 3-tier architecture in OCI:

+---------------------+       +---------------------+       +---------------------+
|  Presentation Layer |       |  Application Layer  |       |      Data Layer     |
|  (Web Tier)         |       |  (App Tier)         |       |  (Database Tier)    |
|                     |       |                     |       |                     |
|  +---------------+  |       |  +---------------+  |       |  +---------------+  |
|  | Load Balancer |  |       |  | App Server 1  |  |       |  |   Database    |  |
|  +---------------+  |       |  +---------------+  |       |  +---------------+  |
|         |           |       |         |           |       |         |           |
|  +---------------+  |       |  +---------------+  |       |                     |
|  | Web Server 1  |  |       |  | App Server 2  |  |       |                     |
|  +---------------+  |       |  +---------------+  |       |                     |
|         |           |       |         |           |       |                     |
|  +---------------+  |       |  +---------------+  |       |                     |
|  | Web Server 2  |  |       |  | App Server 3  |  |       |                     |
|  +---------------+  |       |  +---------------+  |       |                     |
+---------------------+       +---------------------+       +---------------------+

Steps to Implement a 3-Tier Architecture in OCI

1. Set Up the Presentation Layer:

   • Create a VCN (Virtual Cloud Network) and subnets for the web tier.
   • Deploy an OCI Load Balancer in the public subnet.
   • Launch Compute Instances in the public subnet and install web server software (e.g., Apache, Nginx).

2. Set Up the Application Layer:

   • Create a separate subnet for the application tier.
   • Launch Compute Instances in the application subnet and install application server software.
   • Alternatively, deploy applications using OCI Container Engine for Kubernetes (OKE).

3. Set Up the Data Layer:

   • Create a separate subnet for the database tier.
   • Deploy an OCI Autonomous Database or OCI Database in the database subnet.
   • Configure security rules to allow communication between the application tier and the database tier.

4. Configure Security and Networking:

   • Set up security lists or network security groups to control traffic between the tiers.
   • Configure route tables to ensure proper routing of traffic between subnets.

5. Deploy and Test the Application:

   • Deploy your application code to the application servers.
   • Test the end-to-end functionality to ensure that the web tier can communicate with the app tier, and the app tier can communicate with the database tier.

By following these steps, we can implement a robust and scalable 3-tier architecture in Oracle Cloud Infrastructure (OCI). This architecture provides a clear separation of concerns, making it easier to manage and scale each layer independently.