Lab :49 create VCN, 1 subnet using terraform

Requierment:

Network Architecture Design Objective

The primary objective of this phase is to establish a well-structured, scalable, and extensible network architecture for the Application Environment.

The design focuses on optimized IP address management, logical resource segmentation, non-overlapping CIDR allocation, and standardized network resource organization to support current workloads while providing sufficient capacity for future growth and infrastructure expansion.

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Key Design Objectives

1. Establish a Scalable Network Architecture

Design a modular and extensible network topology capable of supporting current application workloads while allowing seamless integration of additional workloads, subnets, services, and infrastructure components as the environment grows.

2. Implement Optimized IP Address Management

Develop a structured CIDR and subnet allocation strategy to ensure efficient utilization of the available IP address space and provide adequate address capacity for current and future workloads.

3. Ensure Network Address Isolation

Prevent CIDR overlap with existing OCI VCNs, on-premises networks, and interconnected environments to maintain predictable routing, avoid address conflicts, and ensure reliable network connectivity.

4. Maintain Reserved Address Capacity

Allocate dedicated IP address space for future expansion, allowing additional subnets, application workloads, infrastructure services, and network components to be introduced without requiring major changes to the existing network architecture.

5. Standardize Resource Naming and Organization

Implement a consistent, descriptive, and environment-aware naming convention across VCNs, subnets, route tables, gateways, security controls, and other OCI resources.

This improves:

• Operational visibility
• Resource identification
• Governance and compliance
• Infrastructure maintainability
• Troubleshooting efficiency
• Terraform resource management

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Architecture Design Principle

Design for today's workload, but architect the network for tomorrow's scale.

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Planning:

Complete Subnet Breakdown

Resource Domain	CIDR Block	Total IPs	Usable IPs	IP Range	Lifecycle Status
blinkit_spoke_VCN	10.0.1.0/24	256	251	10.0.1.0 - 10.0.1.255	Create
Application Subnet	10.0.1.0/25	128	125	10.0.1.0 - 10.0.1.127	Create (Private)
Reserve Subnet 1	10.0.1.128/26	64	61	10.0.1.128 - 10.0.1.191	Planning
Reserve Subnet 2	10.0.1.192/27	32	29	10.0.1.192 - 10.0.1.223	Planning
Future use	10.0.1.224/27	32	29	10.0.1.224 - 10.0.1.255	Unallocated

Dependency flow

Project Structure

Final Terraform Flow