How do I resolve the "Already Exists" error that I receive when I redeploy my AWS CDK code after I delete the stack from the deployment?

Resolution

Most resources in the AWS CDK Construct Library set the removalPolicy property to the RETAIN state by default. If you don't set the removalPolicy property to RETAIN on your resources, then the resources are orphaned. Orphaned resources remain in your AWS account after you delete the stack and then transition to the DELETE_COMPLETE state.

When you update the stack, AWS CDK removes the resource. If you specified a custom name for the resources, then you might receive an "Already Exists" error when you redeploy the same code.

Note: The following steps use an example Amazon Simple Storage Service (Amazon S3) bucket resource that's associated with the s3.Bucket class in AWS CDK.

Example custom-named resource:

const s3Bucket = new s3.Bucket(this, 's3-bucket', {
 bucketName: 'amzn-s3-demo-bucket',
 versioned: false,
 encryption: s3.BucketEncryption.S3_MANAGED
 });

Import the retained resource to your new stack

Complete the following steps:

1. Confirm that your environment meets the requirements to use the cdk import AWS CDK Command Line Interface (CLI) command.
   Note: You can't import a resource into your stack when you update or create other resources in the stack. You can import only one or more resources in a single import operation.

2. Temporarily remove all other resources from your code except for the resource that you want to retain. The defined properties of the resource that you import must match the properties of the resource that you deployed. For example, import the retained S3 bucket resource s3-bucket.
   Note: To import a resource, you must set a Removal Policy for the resource.
   Example policy:

   const s3Bucket = new s3.Bucket(this, 's3-bucket', {
    bucketName: 'amzn-s3-demo-bucket',
    removalPolicy: RemovalPolicy.RETAIN
    });
   
   //const cfnFunction = new lambda.CfnFunction(this, 'MyCfnFunction', {
   //  code: {
   //  ...
   //    s3Bucket: s3Bucket.bucketArn
   //  },
   //  role: 'role',

   Note: Replace s3-bucket with your S3 bucket name.

3. Run the following cdk import command to initiate the resource import:

   cdk import

4. Enter the resource ID when CDK prompts you for it. In this example, enter the name for the S3 bucket.

5. Re-introduce the resources from your code, and then run the following deploy command:

   cdk deploy

Manually delete the retained resource

Complete the following steps:

1. Sign in to the AWS Management Console.
2. Select the service of the resources that you don't want to retain.
3. Manually delete the resources. For example, to remove the s3.bucket resource, delete the Amazon S3 bucket.
4. To redeploy the AWS CDK, run the following deploy command:

   cdk deploy

Change the name of the retained resource

Complete the following steps:

1. Open the AWS CDK code for the resource.
2. Update the name of the resource to a unique value that doesn't conflict with the name of the retained resource:

   const s3Bucket = new s3.Bucket(this, 's3-bucket', {
    bucketName: 'amzn-s3-demo-bucket',
    versioned: false,
    encryption: s3.BucketEncryption.S3_MANAGED
    });

   Note: The preceding example uses the bucketName parameter to change the name of the s3.Bucket resource. Replace amzn-s3-demo-bucket with your S3 bucket name.

Delete the resource name

To delete the resource name so that AWS CDK can generate a unique name, complete the following steps:

1. To remove the resource name from AWS CDK, run the following code:

   const s3Bucket = new s3.Bucket(this, 's3-bucket', {
    versioned: false,
    encryption: s3.BucketEncryption.S3_MANAGED
    });

   Note: The preceding example code removes the bucketName property to allow AWS CDK to generate a new name.
2. To redeploy AWS CDK, run the following deploy command:

   cdk deploy

Set the removalPolicy property to DESTROY

Complete the following steps:

1. Open the AWS CDK code for the resources.

2. Set the removalPolicy property to DESTROY:

   const s3Bucket = new s3.Bucket(this, 's3-bucket', {
    bucketName: 'amzn-s3-demo-bucket',
    removalPolicy: RemovalPolicy.DESTROY
    });

3. To access the AWS CloudFormation template, run the following cdk synth command:

   cdk synth

4. Verify that the DeletionPolicy and UpdateReplacePolicy is set to Delete.