Removing Stacks
If you ever need to delete a Quilt stack from your AWS account, you should know that:
Your data in S3 buckets remains accessible.
You can continue using the Quilt SDK for reading and writing packages.
Stack-managed resources (Athena tables, Postgres database, audit logs) will be affected.
The deletion behavior varies between CloudFormation and Terraform deployments.
I. Impact Assessment and Preparation
What May Be Deleted
Custom configurations specific to the Quilt stack (e.g., IAM roles, resource mappings, permissions).
Analytics data in stack-managed buckets.
Audit logs and Athena querying setups.
User account and tabulator configurations.
Recommended Actions
Export analytics data you need to keep.
Save important audit logs.
Document existing Athena configurations if you'll need to recreate them.
Export the Postgres database (containing, e.g., user accounts and tabulator configuration) in case you want to reuse it for future stacks.
II. Stack Deletion Process
Using CloudFormation
Start the Deletion Process
Navigate to the CloudFormation console in your AWS region.
Select your stack under CloudFormation > Stacks.
Click Delete Stack to begin the process.
Empty or Ignore Non-Deleted Resources
CloudFormation attempts to delete all stack-managed resources.
If a resource cannot be deleted (e.g., non-empty S3 bucket):
It will show a DELETE_FAILED status in the Events tab.
Failed resources remain intact, including non-empty S3 buckets.
Other independent resources will still be deleted.
The stack enters the DELETE_FAILED state.
If you wish to remove those resources:
Back up any important files.
Remove all files from the bucket via the S3 console or CLI.
Retry the deletion process.
Alternatively, you can leave them undeleted, though that may require manual cleanup later.
Using Terraform
Start the Deletion Process
Open a terminal in your Terraform configuration directory.
Run
terraform destroy.
Empty or Retain Non-Deleted Resources
Terraform stops at the first resource it cannot delete (e.g., non-empty S3 buckets created by CloudFormation).
Dependencies of the failed resource are preserved.
To resolve, back up important files and clear the bucket contents.
Once addressed, resume deletion by re-running
terraform destroy.
III. Final Steps
Verify deletion of all non-retained resources.
Confirm that the stack is no longer listed in CloudFormation or Terraform.
Check for any orphaned resources or residual costs using the AWS Cost Explorer.
IV. After Stack Deletion
Your S3 bucket data remains intact and accessible.
The Quilt SDK continues to function for package operations.
Recreate any necessary Athena/Glue configurations if needed.
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