How to Manage Multiple AWS Accounts with AWS Organizations and Best Practices for Security and Cost Control

Table of Contents

1. Why Use Multiple AWS Accounts?
2. Introduction to AWS Organizations
3. How to Set Up AWS Organizations
   • Creating an Organization
   • Inviting Existing AWS Accounts
   • Organizing Accounts into OUs (Organizational Units)
4. Managing Policies with Service Control Policies (SCPs)
5. Consolidated Billing and Cost Management
6. Best Practices for Managing Multiple AWS Accounts
   • Implementing Security Best Practices
   • Cost Optimization Strategies
   • Automation and Monitoring
7. Conclusion

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1. Why Use Multiple AWS Accounts?

Using multiple AWS accounts is a common practice for organizations that need to manage different environments (e.g., development, staging, and production), projects, teams, or business units. It provides several advantages:

• Enhanced Security: You can isolate resources, permissions, and access between different accounts, reducing the risk of unauthorized access or accidental changes.
• Cost Management: Separate accounts make it easier to track costs by project or department and enforce cost control measures.
• Operational Efficiency: You can apply different policies, permissions, and monitoring tools to specific accounts based on their unique needs.
• Resource Organization: Separate accounts allow you to structure and manage AWS resources in a way that aligns with your organization’s architecture.

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2. Introduction to AWS Organizations

AWS Organizations is a service that helps you centrally manage and govern multiple AWS accounts. With AWS Organizations, you can group accounts into Organizational Units (OUs), apply Service Control Policies (SCPs), and set up consolidated billing to manage costs more effectively.Key features of AWS Organizations include:

• Account Management: Create and manage multiple AWS accounts from a central organization.
• Consolidated Billing: Pool costs from all accounts to leverage volume discounts and simplify billing management.
• Service Control Policies (SCPs): Define rules to manage what services and actions are allowed across accounts.
• Automation: Use APIs to automate the creation, governance, and configuration of accounts.

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3. How to Set Up AWS Organizations

Creating an Organization

1. Sign in to AWS Organizations:
   Go to the AWS Management Console, search for AWS Organizations, and click on it.
2. Create a New Organization:
   If you don't already have an organization, click Create Organization. This will set your current AWS account as the management account, which will have the ability to create and manage other accounts.
3. Select Organizational Features:
   Choose All Features to enable full control over accounts or Consolidated Billing if you just need to centralize billing.

Inviting Existing AWS Accounts

1. Go to the Accounts Page:
   In the AWS Organizations dashboard, navigate to Accounts.
2. Invite Existing Accounts:
   You can invite existing AWS accounts to your organization by clicking Add an AWS Account and entering the account’s email or account ID.
3. Send Invitation:
   The invited account will need to accept the invitation via the AWS Organizations console.

Organizing Accounts into OUs (Organizational Units)

Organizational Units (OUs) help you organize your accounts based on their function or purpose, such as separating development from production accounts.

1. Create an OU:
   Navigate to Organizational Units in the AWS Organizations console and click Create Organizational Unit.
2. Add Accounts to the OU:
   Once the OU is created, you can assign specific accounts to it. For example, you might create OUs for different departments, such as Engineering, Finance, or Marketing.
3. Apply Policies:
   You can apply Service Control Policies (SCPs) to OUs to restrict the actions that accounts in the OU can perform. This is useful for enforcing governance and ensuring security compliance.

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4. Managing Policies with Service Control Policies (SCPs)

Service Control Policies (SCPs) are a central feature of AWS Organizations that allow you to enforce granular permissions across accounts. SCPs define the actions that users and roles within accounts can perform, regardless of their individual IAM permissions.

How to Create and Apply SCPs:

1. Navigate to Policies:
   In the AWS Organizations console, go to the Policies tab.
2. Create a New SCP:
   Click Create Policy to write a new SCP. For example, to prevent all accounts in an OU from using certain services, you could create the following policy:
   json

   Copy code

   {
"Version": "2012-10-17",
"Statement": [
{
"Effect": "Deny",
"Action": [
"s3:DeleteBucket",
"ec2:TerminateInstances"
],
"Resource": "*"
}
]
}

3. Attach SCP to an OU:
   After creating the SCP, you can attach it to specific OUs, which will automatically apply the policy to all accounts within that OU.

SCPs are useful for preventing the use of certain AWS services or actions that could incur unwanted costs or violate security policies.

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5. Consolidated Billing and Cost Management

One of the most powerful features of AWS Organizations is Consolidated Billing, which allows you to combine the usage and costs of multiple accounts. This can help you optimize your spending and track costs more easily.

Benefits of Consolidated Billing:

• Cost Optimization: Consolidating billing enables you to take advantage of volume discounts across accounts, such as EC2 Reserved Instances or S3 storage pricing tiers.
• Single Bill: You receive a single bill for all linked accounts, making it easier to manage costs and payments.
• Cost Allocation Tags: Use tags to track and allocate costs to specific projects, departments, or business units.

You can access detailed billing reports and set up budgets to monitor spending across your organization from the AWS Cost Explorer.

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6. Best Practices for Managing Multiple AWS Accounts

Implementing Security Best Practices

• Use Separate Accounts for Different Environments: Create different accounts for development, staging, and production environments to prevent accidental data sharing or interference.
• Apply SCPs for Governance: Use SCPs to enforce security and compliance policies, such as blocking access to certain regions or restricting the use of specific services.
• Enable Multi-Factor Authentication (MFA): Ensure MFA is enabled on all accounts, especially the management account, to enhance security.
• Use IAM Roles and Least Privilege Access: Create granular IAM roles with least privilege access and avoid sharing root account credentials.

Cost Optimization Strategies

• Track and Monitor Costs: Use AWS Cost Explorer to regularly monitor costs across all accounts. Set up alarms for unusual spikes in usage.
• Use Reserved Instances and Savings Plans: Purchase EC2 Reserved Instances and Savings Plans across the organization to take advantage of discounted pricing.
• Implement Budgets and Alerts: Set up AWS Budgets to monitor spending and receive alerts when costs exceed predefined thresholds.

Automation and Monitoring

• Automate Account Creation: Use AWS Organizations API to automate the creation of new accounts and apply SCPs automatically.
• Monitor Account Activity: Use AWS CloudTrail to track and monitor all activity across accounts. CloudTrail logs can help you detect suspicious behavior or unauthorized access.
• Set Up Centralized Logging: Implement centralized logging using AWS CloudWatch Logs to collect logs from all accounts in one place for easier monitoring.

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7. Conclusion

Managing multiple AWS accounts with AWS Organizations provides greater flexibility, security, and cost control as your cloud infrastructure scales. By following best practices such as separating environments, implementing Service Control Policies, and utilizing consolidated billing, you can ensure that your organization runs smoothly and efficiently.Whether you’re just starting with AWS or managing a large enterprise, AWS Organizations offers the tools and automation you need to manage your cloud resources effectively.

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