Hi Jon,
Yes, typically you would want one Web Adaptor for Server, one Web Adaptor for Portal, and a Web Adaptor for each licensing role (Image Server, GeoEvent, etc). The reason why you would need a separate Web Adaptor for each licensing role is because these servers operate as additional ArcGIS Server sites federated with your Portal, and otherwise the end-user would have to access the sites through the port number, which is not a security best-practice.
The way that you laid it out in your original post:
- Portal: /portal
- GIS Server: /server
- Image Server: /image
- GeoEvent Server: /geoevent
This would be perfect for this kind of deployment. You will need to install and configure each Web Adaptor separately; for example, even if Portal and GIS Server are on the same machine, you will need to run the Web Adaptor installation twice.
Hope this helps!
- Rachel