Final answer:
The minimum size for the subnet depends on the specific requirements of the EC2 instances.
Step-by-step explanation:
The minimum size that you need for your subnet would depend on the specific requirements of each EC2 instance. Each instance requires a certain amount of memory (RAM) and storage space (disk space), as well as a certain number of CPU cores. To determine the minimum size for your subnet, you will need to calculate the total resources required by all 28 EC2 instances.
For example, if each EC2 instance requires 2 GB of RAM, 50 GB of disk space, and 2 CPU cores, then the minimum size for your subnet would need to have a total of at least 56 GB of RAM, 1400 GB of disk space, and 56 CPU cores.
Keep in mind that you may also need to account for other factors such as network bandwidth and security requirements when determining the appropriate size for your subnet.