Customize accounts with Account Factory Customization (AFC) - AWS Control Tower

Customize accounts with Account Factory Customization (AFC)

AWS Control Tower allows you to customize new and existing AWS accounts when you provision their resources from the AWS Control Tower console. After you set up account factory customization, AWS Control Tower automates this process for future provisioning, so you don't have to maintain any pipelines. Customized accounts are available for use immediately after the resources are provisioned.

Your customized accounts are provisioned in account factory, through AWS CloudFormation templates. You'll define an AWS CloudFormation template that serves as customized account blueprint. Your blueprint describes the specific resources and configurations you require when an account is provisioned. Pre-defined blueprints, built and managed by AWS partners, also are available. For more information about partner-managed blueprints, see the AWS Service Catalog Getting Started Library.

Note

AWS Control Tower contains proactive controls, which monitor AWS CloudFormation resources in AWS Control Tower. Optionally, you can activate these controls in your landing zone. When you apply proactive controls, they check to make sure that the resources you're about to deploy to your accounts are compliant with your organization's policies and procedures. For more information about proactive controls, see Proactive controls.

Your account blueprints are stored in an AWS account, which for our purposes is referred to as a hub account. Blueprints are stored in the form of an AWS Service Catalog product. We call this product a blueprint, to distinguish it from any other AWS Service Catalog products. To learn more about how to create AWS Service Catalog products, see Creating products in the AWS Service Catalog Administrator Guide.

You can apply customized blueprints to existing accounts, also, by following the Update account steps in the AWS Control Tower console. For details, see Update the account in the console.

Before you begin

Before you begin to create customized accounts with AWS Control Tower Account Factory, you must have an AWS Control Tower landing zone environment deployed, and you must have an organizational unit (OU) registered with AWS Control Tower, where your newly created accounts will be placed.

Preparation for customization
  • You may create a new account to serve as the hub account, or you may use an existing AWS account. We strongly recommend that you do not use the AWS Control Tower management account as your blueprint hub account.

  • You must configure the hub account as a delegated administrator for AWS Service Catalog. For more information, see Simplify sharing your AWS Service Catalog portfolios in an AWS Organizations setup.

  • If you plan to enroll AWS accounts into AWS Control Tower and customize them, you must first add the AWSControlTowerExecution role to those accounts, as you would for any other account you are enrolling into AWS Control Tower.

  • If you plan to use partner blueprints that have marketplace subscription requirements, you must configure these from your AWS Control Tower management account before you deploy the partner blueprints as account factory customization blueprints.

Note

One blueprint may be deployed per AWS Control Tower account.

Considerations for Account Factory Customizations (AFC)

  • AFC supports customization using a single AWS Service Catalog blueprint product only.

  • The AWS Service Catalog blueprint hub account must be a delegated administrator for the AWS Service Catalog service within the same organization. For more information, see Delegated admin.

  • The AWS Service Catalog blueprint products must be created in the hub account, and in the same Region as the AWS Control Tower landing zone home Region.

  • The AWSControlTowerBlueprintAccess IAM role must be created with the proper name, permissions, and trust policy.

  • AWS Control Tower supports two deployment options for blueprints: deploy to the home Region only, or deploy to all Regions governed by AWS Control Tower. Selection of Regions is not available.

  • When you update a blueprint in a member account, the blueprint hub account ID and the AWS Service Catalog blueprint product cannot be changed.

  • AWS Control Tower doesn't support removing an existing blueprint and adding a new blueprint in a single blueprint update operation. You can remove a blueprint and then add a new blueprint in separate operations.

  • AWS Control Tower changes behavior, based on whether you are creating or enrolling customized accounts, or non-customized accounts. If you are not creating or enrolling customized accounts with blueprints, AWS Control Tower creates an Account Factory provisioned product (through AWS Service Catalog) in the AWS Control Tower management account. If you are specifying customization when creating or enrolling accounts with blueprints, AWS Control Tower does not create an Account Factory provisioned product in the AWS Control Tower management account.

In case of a blueprint error

Error while applying a blueprint

If an error occurs during the process of applying a blueprint to an account—either a new account or an existing account that you are enrolling into AWS Control Tower—the recovery procedure is the same. The account will exist, but it is not customized, and it is not enrolled into AWS Control Tower. To continue, follow the steps to enroll the account into AWS Control Tower, and add the blueprint at time of enrollment.

Error while creating the AWSControlTowerBlueprintAccess role, and workarounds

When you create the AWSControlTowerBlueprintAccess role from an AWS Control Tower account, you must be signed in as the principal using the AWSControlTowerExecution role. If you are signed in as any other, the CreateRole operation is prevented by an SCP, as shown in the artifact that follows:

{ "Condition": { "ArnNotLike": { "aws:PrincipalArn": [ "arn:aws:iam::*:role/AWSControlTowerExecution", "arn:aws:iam::*:role/stacksets-exec-*" ] } }, "Action": [ "iam:AttachRolePolicy", "iam:CreateRole", "iam:DeleteRole", "iam:DeleteRolePermissionsBoundary", "iam:DeleteRolePolicy", "iam:DetachRolePolicy", "iam:PutRolePermissionsBoundary", "iam:PutRolePolicy", "iam:UpdateAssumeRolePolicy", "iam:UpdateRole", "iam:UpdateRoleDescription" ], "Resource": [ "arn:aws:iam::*:role/aws-controltower-*", "arn:aws:iam::*:role/*AWSControlTower*", "arn:aws:iam::*:role/stacksets-exec-*" ], "Effect": "Deny", "Sid": "GRIAMROLEPOLICY" }

The following workarounds are available:

  • (Most recommended) Assume the AWSControlTowerExecution role and create the AWSControlTowerBlueprintAccess role. If you choose this workaround, be sure to sign out from the AWSControlTowerExecution role immediately afterward, to prevent unintended changes to resources.

  • Sign into an account that is not enrolled in AWS Control Tower, and therefore not subject to this SCP.

  • Temporarily edit this SCP to permit the operation.

  • (Strongly not recommended) Use your AWS Control Tower management account as your hub account, so it is not subject to the SCP.

Customizing your policy document for AFC blueprints

When you enable a blueprint through account factory, AWS Control Tower directs AWS CloudFormation to create a StackSet on your behalf. AWS CloudFormation requires access to your managed account to create AWS CloudFormation stacks in the StackSet. Although AWS CloudFormation already has administrator privileges in the managed account through the AWSControlTowerExecution role, this role is not assumable by AWS CloudFormation.

As part of enabling a blueprint, AWS Control Tower creates a role in the member account, which AWS CloudFormation may assume to complete the StackSet management tasks. The simplest way to enable your customized blueprint through account factory is to use an allow-all policy, because those policies are compatible with any blueprint template.

However, best practices suggest that you must restrict the permissions for AWS CloudFormation in the target account. You can provide a customized policy, which AWS Control Tower applies to the role it creates for AWS CloudFormation to use. For example, if your blueprint creates an SSM Parameter called something-important, you could provide the following policy:

{ "Version": "2012-10-17", "Statement": [ { "Sid": "AllowCloudFormationActionsOnStacks", "Effect": "Allow", "Action": "cloudformation:*", "Resource": "arn:aws:cloudformation:*:*:stack/*" }, { "Sid": "AllowSsmParameterActions", "Effect": "Allow", "Action": [ "ssm:PutParameter", "ssm:DeleteParameter", "ssm:GetParameter", "ssm:GetParameters" ], "Resource": "arn:*:ssm:*:*:parameter/something-important" } ] }

The AllowCloudFormationActionsOnStacks statement is required for all AFC custom policies; AWS CloudFormation uses this role to create stack instances, therefore it requires permission to perform AWS CloudFormation actions on stacks. The AllowSsmParameterActions section is specific to the template being enabled.

Resolve permission issues

When you enable a blueprint with a restricted policy, you may find that there are insufficient permissions to enable the blueprint. To resolve these issues, revise your policy document and update the member account's blueprint preferences to use the corrected policy. To check that the policy is sufficient to enable the blueprint, ensure that the AWS CloudFormation permissions are granted, and that you can create a stack directly using that role.