"What are the best practices for managing enterprise-scale AWS accounts and resources to achieve cost optimization and operational efficiency?"

For managing enterprise-scale AWS accounts and resources effectively, several best practices should be adopted:

1. Implement AWS Organizations: Use AWS Organizations to centrally manage multiple accounts, enabling consolidated billing, security controls, and resource sharing across your enterprise.

2. Create a well-structured account hierarchy: Establish a logical organization of accounts using Organizational Units (OUs). Common OUs include Security, Infrastructure, Sandbox, Workloads, and Policy Staging. This structure allows for better management and application of policies.

3. Use Service Control Policies (SCPs): Apply SCPs at the OU level to enforce security boundaries and control access to AWS services across accounts.

4. Implement least privilege access: Limit access to the management account and delegate responsibilities to member accounts where possible. Use IAM roles with appropriate permissions for administrative tasks.

5. Standardize account naming and tagging: Use consistent naming conventions and custom tags for easier identification and management of accounts.

6. Implement a multi-account strategy: Separate workloads, environments (e.g., development, testing, production), and business units into different accounts for better isolation and management.

7. Utilize AWS Control Tower: Leverage AWS Control Tower to set up and govern a secure, compliant, multi-account environment based on best practices.

8. Implement cost optimization strategies: Use consolidated billing, implement tagging policies, and regularly review and optimize resource usage across accounts.

9. Establish governance and compliance processes: Implement continuous auditing and compliance checks using services like AWS Config and AWS CloudTrail.

10. Manage account lifecycle: Before creating new accounts, check if similar ones already exist to avoid duplication. Implement a cleanup process for reusing accounts instead of closing and creating new ones.

11. Secure root accounts: Avoid using root accounts for administrative tasks, enable multi-factor authentication, and create alternate contacts for billing, operations, and security.

12. Test policy changes: Use a Policy Staging OU to test proposed policy changes before applying them broadly to the organization.

By adopting these practices, enterprises can achieve better cost optimization, operational efficiency, and maintain a secure and compliant AWS environment at scale.

Sources
Best practices for the management account - AWS Organizations
Best practices for member accounts - AWS Organizations
Community | Manage Security and Costs Across the Enterprise With AWS Organizations
Best practices for managing organizational units (OUs) with AWS Organizations - AWS Organizations
Know Before You Go – AWS re:Invent 2024 Cloud Governance and Compliance | AWS Cloud Operations Blog