Unable to delete cfn stack, role is invalid or cannot be assumed

Question

I'm new to aws cloudformation; I'm wondering if anybody knows of a way to force delete a stack when it just won't delete. It fails with this error:

Failed to delete stack: Role arn:aws:iam::role/CloudFormationRole-NestedCFN-CodePipeline is invalid or cannot be assumed

This error usually happens when I try to delete a nested child stack instead of starting by deleting the parent stack first. Is there any way to delete the nested stack if I accidentally deleteted the parent stack?

Answer 1

I got the same problem and the only way to delete the stack was using the AWS CLI and executing the following command:

aws cloudformation delete-stack --role-arn arn:aws:iam::xxxx:role/anyrolewithpermissions --stack-name StuckStack

just be sure to use another role with enough permissions.

Answer 2

I've had this problem a few times. The solution is a bit of a hack. In your case, you need to create a new role named CloudFormationRole-NestedCFN-CodePipeline. When you create this role, you'll likely need to select the CloudFormation service when it asks you to Choose the service that will use this role and then Attach permissions policies. Once the role is created, try to delete the stack again.
Some of this is a guessing game because you need to choose the correct resource (i.e. AWS service) that is a "trusted entity". Based on your role name, it's either CloudFormation or CodePipeline.

After you delete the CloudFormation stack, you can delete the IAM role you just created.

The reason you get this error is because you probably deleted a CloudFormation stack that has an IAM role that's being used by the stack you're trying to delete.

I wish there was a more elegant solution from AWS but this was my workaround.

Answer 3

This usually happens when a role required to delete the stack has been accidentally deleted. You may get the error message

Role arn:aws:iam::<account>:role/<role name> is invalid or cannot be assumed

Go to IAM > roles > create role > click on cloudformation for the service > make sure you give it the right permissions so that cloudformation can delete the stack. (In my case I gave it admin permissions because I was planning to delete the role straight after I deleted the stack > for Role name use the same role name in the error message.

You should now be able to delete the stack

Answer 4

Unfortunately there is no way to force delete a CF Stack.

Couple of things that you can try:

1. Delete the conflicting resource manually and then re-initiate stack deletion.
2. Delete the conflicting resource from the CF template and update the Stack with it.

Answer 5

In my case, I deleted the pipeline that created the stack(s) and this removed the Role used by the stack.

Option 1) Role up another pipeline from the pipeline stack, then "update" the stack you can't delete, but tell it to use the new role created by the pipeline. Then delete the stack (even if update fails, the new role is still in play, and you can delete).

Option 2) Create a role matching the role you have deleted (in my case it was as below) and then update stack using this role, then delete.

CloudformationServiceRole:
  Type: AWS::IAM::Role
  Properties:
    AssumeRolePolicyDocument:
      Statement:
      - Action:
        - sts:AssumeRole
        Effect: Allow
        Principal:
          Service:
          - cloudformation.amazonaws.com
      Version: '2012-10-17'
    Path: "/"
    Policies:
      - PolicyName: DeployCloudformationStack
        PolicyDocument:
          Version: '2012-10-17'
          Statement:
          - Resource: "*"
            Effect: Allow
            Action:
            - "*" 

There may be other repairs to do afterwards !

Answer 6

An easier way to solve this issue is to use a change set. The following steps can be followed

1. Create a role with the correct rights
2. Select the stack you wish to delete and create change set
3. In the change set, use the existing template, navigate through the wizard but change the IAM role it uses
4. Then create and execute the change set.

Then you can delete the stack accordingly

Answer 7

This generally occurs in case of nested stacks. Simply create a role with the same name and grant full administrator access permission to the role.With this permission power the role will be able to delete the stack. Delete the role after successful stack deletion