Limitations and quotas in AWS Control Tower

This chapter covers the AWS service limitations and quotas that you should keep in mind as you use AWS Control Tower. If you're unable to set up your landing zone due to a service quota issue, contact AWS Support.

For more information about limitations that are specific to controls, see Control limitations.

The Controls Reference Guide

Detailed information about AWS Control Tower controls has been moved to the AWS Control Tower Controls Reference Guide.

Known limitations in AWS Control Tower

This section describes known limitations and unsupported use cases in AWS Control Tower.

• AWS Control Tower has overall concurrency limitations. In general, one operation at a time is permitted. Two exceptions to this limitation are allowed:

  • Optional controls can be activated and deactivated concurrently, through an asynchronous process. Up to one hundred (100) control-related operations at a time can be in progress, in total, no matter if they are called from the console or from an API. Of these 100 operations, up to 20 at a time can be proactive control operations.

  • Accounts can be provisioned, updated, and enrolled concurrently in Account Factory, through an asynchronous process, with up to five (5) account-related operations in progress simultaneously. Unmanaging accounts must be performed one account at a time.

• Email addresses of shared accounts in the Security OU can be changed, but you must update your landing zone to see these changes in the AWS Control Tower console.

• A limit of five (5) SCPs per OU applies to OUs in your AWS Control Tower landing zone.

• AWS Control Tower supports up to 10,000 accounts in your landing zone's organization, divided among all of your OUs.

• Existing OUs with over 1000 directly nested accounts cannot be registered or re-registered in AWS Control Tower. For more information about limitations with registering OUs, see Limitations based on underlying AWS services.

• Customizations for AWS Control Tower (CfCT) is unavailable in these AWS Regions, because some dependencies are not available:

  • Europe (Zurich) Region, eu-central-2

  • Europe (Spain) Region, eu-south-2

  • Canada West (Calgary)

  You can deploy and manage resources in these Regions with CfCT, if you deploy CfCT to your AWS Control Tower home Region, but you cannot build CfCT in these Regions.

• AWS Control Tower Account Factory for Terraform (AFT) is not available in the following AWS Regions, because some dependencies are not available:

  • Europe (Zurich) Region, eu-central-2

  • Europe (Spain) Region, eu-south-2

  • Canada West (Calgary)

• AWS Control Tower Account Factory for Terraform (AFT) cannot be deployed by new AFT customers in the following Regions, because AWS CodeStar Connections is not available to connect to a third-party version control system (VCS):

  • Asia Pacific (Hong Kong), Africa (Cape Town), Middle East (Bahrain), Europe (Zurich), Asia Pacific (Jakarta), Asia Pacific (Hyderabad), Asia Pacific (Osaka), Asia Pacific (Melbourne), Israel (Tel Aviv), Europe (Spain), and Middle East (UAE)

• The following Regions do not support IAM Identity Center.

  • Middle East (UAE) Region, me-central-1

  • Asia Pacific (Hyderabad) Region, ap-south-2

  • Canada West (Calgary), ca-west-1

  For more information about AWS Regions and support for IAM Identity Center, see Regions and endpoints in the AWS Identity and Access Management User Guide.

• The following Regions do not support AWS Service Catalog.

  • Canada West (Calgary), ca-west-1

  For more information about AWS Control Tower functionality in Regions that do not support AWS Service Catalog, see AWS Control Tower available in AWS Canada West (Calgary).

• When calling a control API to activate or deactivate a control, the limit for EnableControl and DisableControl updates in AWS Control Tower is one hundred (100) concurrent operations. Ten operations (10) can be in progress simultaneously, with the remaining operations queued. You may need to adjust your code to wait for completions.

• Within the overall limit of 100 control operations, up to 20 operations at a time can be proactive control operations.

• When you provision accounts through Account Factory Customizations (AFC), with blueprints that are based in Terraform, you can deploy those blueprints to only one AWS Region. By default, AWS Control Tower deploys to the home Region.