About this task
You can apply changes to an existing CloudFormation stack by updating the stack with a newer CloudFormation template. Changes to the stack can include additional nodes, new resources, and new port configuration. The system updates all the objects contained in the stack to match the new settings. Existing EBS volumes and S3 buckets are preserved.
To update an existing single-node stack you must use a new single-node stack template. To update an existing cluster you must use a new multi-node stack template. If you are expanding a cluster, you must already have a cluster with two or more nodes. You cannot expand a single AWS node into an AWS cluster