60_1 ‐ Overview of 3‐Tier Architecture - SanjeevOCI/Ocidocs GitHub Wiki

3-Tier Architecture in Oracle Cloud Infrastructure (OCI)

A 3-tier architecture in OCI separates an application into three layers: Presentation, Application, and Data. This design improves scalability, security, and manageability.

1. Presentation Tier

  • Role: User interface; handles user interactions.
  • OCI Services: Load Balancer, public subnet, web servers (e.g., Apache, Nginx).
  • Access: Publicly accessible via the internet.

2. Application Tier

  • Role: Processes business logic and application workflows.
  • OCI Services: Compute instances (VMs/BMs), private subnet, container services (OKE).
  • Access: Only accessible from the Presentation tier; not exposed to the internet.

3. Data Tier

  • Role: Stores and manages data.
  • OCI Services: Autonomous Database, DB Systems, Object Storage.
  • Access: Only accessible from the Application tier; most secure layer.

Typical OCI Deployment

[Internet]
    |
[Load Balancer] (Public Subnet)
    |
[Web Servers] (Presentation Tier)
    |
[App Servers] (Application Tier, Private Subnet)
    |
[Database] (Data Tier, Private Subnet)

Key OCI Components

  • Virtual Cloud Network (VCN): Isolates resources and controls traffic.
  • Subnets: Public for frontend, private for app/data tiers.
  • Security Lists/NSGs: Restrict access between tiers.
  • Load Balancer: Distributes traffic to web servers.
  • IAM Policies: Control access to resources.

Best Practices

  • Use private subnets for application and data tiers.
  • Restrict inbound/outbound traffic with security lists and NSGs.
  • Use OCI Load Balancer for high availability.
  • Enable backups and monitoring for databases.
  • Apply least privilege IAM policies.

References