How to setup multiple AWS Accounts through Organization

Hello.

AWS re:Post Agent's AI-powered automated responses are partially correct, but partially incorrect.
Using AWS Organizations or Control Tower, you can create AWS accounts via the AWS API.
However, you can only create up to 5 accounts at a time, so you cannot create 1000 accounts in one go.
The process involves creating 5 accounts, then 5 more, and so on.
Therefore, it is difficult to create a large number of accounts simultaneously in a short period of time, so I recommend creating your AWS account in advance.
https://docs.aws.amazon.com/organizations/latest/userguide/orgs_reference_limits.html
https://docs.aws.amazon.com/controltower/latest/userguide/limits.html

This AWS blog post from 2022 describes a system for automating account creation.
https://aws.amazon.com/jp/blogs/mt/how-to-automate-the-creation-of-multiple-accounts-in-aws-control-tower/

When setting up multiple AWS accounts through AWS Organizations, you have flexibility in how you create and manage them. Here's what you need to know:

Account Creation Approach: AWS Organizations allows you to automate AWS account creation and management, so you don't need to create accounts manually. You can programmatically create accounts on-demand or pre-provision them based on your needs. For your CloudLabs use case, you could either:

• Create accounts on-the-fly when users start a lab session
• Pre-configure a pool of accounts and assign them to users as needed

Automation for Bulk Account Creation: You definitely don't need to create 1,000 accounts manually. AWS Organizations provides automation capabilities for account creation. You can use infrastructure as code approaches to programmatically create multiple accounts at scale. This is especially important as the number of accounts grows, since manual processes become impractical.

Organizational Structure: When creating your account structure, you'll first need to designate a management account (also called the payer account). This account will be used solely for organizational management purposes - no workload resources should be created in it. All your lab accounts would be member accounts under this management account.

You can organize these accounts into organizational units (OUs) to logically group them, which helps with governance and policy management. For example, you might group accounts by lab type, environment, or user cohort.

Best Practices:

• Keep all workload resources in member accounts only
• Use the management account exclusively for provisioning new accounts and administering the organization
• Implement consolidated billing to aggregate costs across all accounts
• Use Service Control Policies (SCPs) to define maximum permissions across your organization

For a streamlined setup experience with automatic deployment, AWS Control Tower can simplify the process of establishing and managing your multi-account environment at scale.
Sources
Set up an organization - AWS Prescriptive Guidance
COST02-BP03 Implement an account structure - AWS Well-Architected Framework
Implementation - Organizing Your AWS Environment Using Multiple Accounts