Step 1. Create the required role - AWS Control Tower

Step 1. Create the required role

Before you begin to customize accounts, you must set up a role that contains a trust relationship between AWS Control Tower and your hub account. When assumed, the role grants AWS Control Tower access to administer the resources in the hub account. The role must be named AWSControlTowerBlueprintAccess.

AWS Control Tower assumes this role to create a Portfolio resource on your behalf in AWS Service Catalog, then to add your blueprint as a Service Catalog Product to this Portfolio, and then to share this Portfolio, and your blueprint, with your member account during account provisioning.

You'll create the AWSControlTowerBlueprintAccess role, as explained in the following sections. You can set up the role in an enrolled or an unenrolled account.

Navigate to the IAM console to set up the required role.

To set up the AWSControlTowerBlueprintAccess role in an enrolled AWS Control Tower account

  1. Federate or sign in as the principal in the AWS Control Tower management account.

  2. From the federated principal in the management account, assume or switch roles to the AWSControlTowerExecution role in the enrolled AWS Control Tower account that you select to serve as the blueprint hub account.

  3. From the AWSControlTowerExecution role in the enrolled AWS Control Tower account, create the AWSControlTowerBlueprintAccess role with proper permissions and trust relationships.

Important

To comply with AWS best practices guidance, it's important that you sign out of the AWSControlTowerExecution role immediately after you create the AWSControlTowerBlueprintAccess role.

To prevent unintended changes to resources, the AWSControlTowerExecution role is intended for use by AWS Control Tower only.

If your blueprint hub account isn't enrolled in AWS Control Tower, the AWSControlTowerExecution role won't exist in the account, and there's no need to assume it before you continue with setting up the AWSControlTowerBlueprintAccess role.

To set up the AWSControlTowerBlueprintAccess role in an unenrolled member account

  1. Federate or sign in as a principal in the account that you wish to designate as the hub account, by means of your preferred method.

  2. When signed in as the principal in the account, create the AWSControlTowerBlueprintAccess role with proper permissions and trust relationships.

The AWSControlTowerBlueprintAccess role must be set up to grant trust to two principals:

  • The principal (user) that runs AWS Control Tower in the AWS Control Tower management account.

  • The role named AWSControlTowerAdmin in the AWS Control Tower management account.

Here's an example trust policy, similar to one you will need to include for your role. This policy demonstrates the best practice of granting least-privilege access. When you make your own policy, replace the term YourManagementAccountId with the actual acccount ID of your AWS Control Tower management account, and replace the term YourControlTowerUserRole with the identifier of the IAM role for your management account.

JSON
{
    "Version":"2012-10-17",		 	 	 
    "Statement": [
        {
            "Effect": "Allow",
            "Principal": {
                "AWS": [
                    "arn:aws:iam::111122223333:role/service-role/AWSControlTowerAdmin",
                    "arn:aws:iam::111122223333:role/YourControlTowerUserRole"
                ]
            },
            "Action": "sts:AssumeRole"
        }
    ]
}

Required permissions policy

AWS Control Tower requires that the managed policy named AWSServiceCatalogAdminFullAccess must be attached to the AWSControlTowerBlueprintAccess role. This policy provides permissions that AWS Service Catalog looks for when it allows AWS Control Tower to administer your portfolio and AWS Service Catalog Product resources. You can attach this policy when you're creating the role in the IAM console.

Additional permissions may be required

  • If you store your blueprints in Amazon S3, AWS Control Tower also requires the AmazonS3ReadOnlyAccess permission policy for the AWSControlTowerBlueprintAccess role.

  • The AWS Service Catalog Terraform type of product requires you to add some additional permissions to the AFC custom IAM policy, if you don't utilize the default Admin policy. It requires these in addition to the permissions required to create the resources that you define in your terraform template.