Update only the resource that has been changed

Whenever we have to update a stack, instead of updating the stack, the existing stack will be deleted and a new stack will be recreated. For example, if we want to update the stack name, say from my_stack1 to my_stack2. For this to happen, the my_stack1 will be deleted and recreated with the name my_stack2. This will be a burden in the production scenario with large number of servers.

Solution:
A mechanism must be introduced to compare the existing template and the template which is input to update the existing stack.Only the delta between them can be taken and updated which will decrease the overhead on the heat engine and increases performance.

Features:
The Blueprint feature is to compare the templates and update accordingly.
For example:
1. If only name changes it can change the name and update in database accordingly.
2. If there is a change in the count it has to create and delete based on new template.

Advantages:
1. Decreases overhead by avoiding stack recreation for each update
2. Increases the performance in production scenarios.