Why Multiple Subscriptions in Azure Landing Zone

Using multiple subscriptions in an Azure Landing Zone offers several benefits compared to using a single subscription for everything. This approach is particularly advantageous for larger organizations or those with complex cloud environments. Here are the key benefits and problems it solves:

1. Improved Security and Isolation

• Risk Mitigation: Separating workloads into different subscriptions can limit the impact of security breaches. If one subscription is compromised, it doesn’t necessarily affect the others.
• Data Isolation: Critical workloads or data can be isolated in separate subscriptions, enhancing security and compliance.

2. Enhanced Governance and Compliance

• Tailored Policies: Different subscriptions can have specific governance policies and compliance standards, catering to the unique requirements of each workload or department.
• Easier Compliance Management: It's easier to manage compliance requirements when different environments (like development, testing, and production) are separated.

3. Simplified Cost Management and Billing

• Cost Visibility: Having separate subscriptions for different departments or projects provides clearer cost visibility and simplifies budgeting.
• Billing Segregation: Separating subscriptions allows for more straightforward billing management, especially when different teams or departments have their own budgets.

4. Resource and Access Management

• Granular Access Control: Multiple subscriptions enable more granular control over access and permissions, reducing the risk of overprivileged accounts.
• Limit Management: Azure imposes certain limits at the subscription level. Splitting workloads across multiple subscriptions can help avoid hitting these limits.

5. Scalability and Flexibility

• Easier Scaling: Managing growth and scaling resources can be more manageable when workloads are distributed across multiple subscriptions.
• Flexible Resource Allocation: Different subscriptions can be more easily aligned with changing business units, teams, or projects.

6. Disaster Recovery

• Better Disaster Recovery Options: Having separate subscriptions can aid in implementing a comprehensive disaster recovery strategy, ensuring not all resources are located in the same subscription.

7. Organizational Structure Alignment

• Departmental Alignment: In large organizations, different departments or business units can have their own subscriptions, aligning their cloud usage with their specific operational structures.

Use Case Scenario

Imagine a large enterprise, "XYZ Corp," with diverse operations including development, production, HR, and finance. By using multiple subscriptions, XYZ Corp can:

• Isolate development environments from production, reducing the risk of accidental impacts on production systems.
• Apply specific compliance controls to the finance department’s subscription which handles sensitive financial data.
• Manage and track costs more effectively for each department, aligning with their individual budgets.
• Implement distinct access controls and security policies tailored to the needs of each department.

Conclusion

While a single subscription might suffice for smaller organizations or less complex environments, multiple subscriptions offer significant advantages in terms of security, compliance, cost management, and scalability for larger or more complex Azure deployments. This approach aligns with best practices for enterprise cloud management, particularly in organizations with diverse needs and operational structures.