@Venkata Sudheer Kumar M
Currently there is no way in Cloudbreak to reuse the same AWS instances in a future deployment. When you terminate a cluster then you terminate the whole infrastructure (Vpc, IGW, Instances, Disks).
Custom AMI is a different thing. Some of the enterprise company have their own certified AMI's. They are only allowed to use those images. For example our base images based on centos7 but if you want to use ubuntu or any other distribution then you have to prepare your own images for Cloudbreak.
What is your use case? why do you want to use the same instances? Do you want to decrease the cost ?