Fixing AWS Control Tower Baseline resources

Problem

When updating AWS Control Tower accounts after a landing zone upgrade, you may find that some dev has messed up the Control Tower resources or attempted to remove a Stack when they shouldn't. This can lead to the account updates failing for various reasons.

You may see something like...

AWS Control Tower failed to deploy one or more stack set instances: StackSet Id: AWSControlTowerBP-BASELINE-CONFIG:4ef4fefe-1234-4659-938c-fd6da95c0e76, Stack instance Id: arn:aws:cloudformation:us-east-1:406111111874:stack/StackSet-AWSControlTowerBP-BASELINE-CONFIG-c46feddd-1234-459c-aa45-132e23e4d36c/43406ac0-928a-11ec-9017-0eb6c2b8c189, Status: OUTDATED, Status Reason: Stack:arn:aws:cloudformation:us-east-1: 406111111874:stack/StackSet-AWSControlTowerBP-BASELINE-CONFIG-c46feddd-1234-459c-aa45-132e23e4d36c/43406ac0-928a-11ec-9017-0eb6c2b8c189 is in DELETE_FAILED state and can not be updated.

Or maybe you hit something like...

AWS Control Tower cannot create the Config deliverychannel aws-controltower-BaselineConfigDeliveryChannel because the delivery channel already exists. To continue, delete the existing Config deliverychannel and try again. 

Sometimes it is easiest to just remove the Stack resources and redeploy.  That being said, trying to do this with the baseline configurations in Control Tower can be tricky.  Removal of baseline configurations are usually prevented by a SCP Guardrail that needs to be temporarily disabled so you can remove the resources before triggering a redeployments. 

Steps

  • Log into the Master Payer and navigate to the AWS Organizations page. 
  • Select the OU that the account resides under.
  • Select the Policies section.
  • Document the policies that have been applied to this OU. You want to find the aws-guardrails-XXXXX policy.  This is important so you can reattach it later.
  • Select the radio button next to the aws-guardrails-XXXXXX policy and detach it. 
  • Log into the account with the broken resources and nagivate to the CloudFormations page.  Make sure you are in the correct region.
  • Depending on the baseline, you should be able to delete the stack.
  • After deleting the stack, you will want to redeploy it by updating Stack Set instance in the master payer. Using the AWS CLI, after making sure you have set your Profile and Region to match the Master Payer's Control Tower region run something like... 
aws cloudformation update-stack-instances --stack-set-name AWSControlTowerBP-BASELINE-CONFIG --accounts 406111111874 --regions us-east-1

  • After confirming that the resources have been redeployed, you will want to re-enable the guardrail on the OU. Navigate to the OU in the AWS Organizations page of the Master Payer and then make sure to attach the aws-guardrails-XXXXXX policy.
  • You should now be OK to try re-registering the OU in Control Tower to complete the update.
Related AWS Documentation


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