Hello, We are planning to setup a DevTest 10.3 instance on our OpenStack Cloud with the Linux OS. We would like to know the capacity requirement for each DevTest Server component 
1. Registry 
2. Enterprise Dashboard 
3. Virtual Service Environment 
4. Coordinator 
5. Simulator 
6. SQL DB

Release:
Component: ITKOTF

Here are some documentation links for you to review. 

https://docops.ca.com/devtest-solutions/10-3/en 
https://docops.ca.com/devtest-solutions/10-3/en/installing/preinstallation/system-requirements 
https://docops.ca.com/devtest-solutions/10-3/en/using 
https://communities.ca.com/docs/DOC-231168663 

While we provide general advice, we are unable to provide assistance with, or recommendations for, specific configurations as these are highly dependent on factors such as workload, shared resources and so forth, in addition to machine specification and execution environment. 

We would recommend that you contact CA Professional Services via your account manager in order to obtain assistance in this instance.