Best deployment model for multiple IIS sites on a cluster of servers

So we are new to Octopus and have gotten a single deployment working but what we are failing to probably grasp is how to scale out. Our model is slowly starting with on-prem systems and eventually expanding to the cloud but our current needs are:

  • We have (as an example) 5 windows servers.
  • Each server will run multiple IIS sites.
  • Each site being a different version or same version but different environments (Dev, Test, Smoke, Validation, etc).
  • Each server will have different combinations of versions and environment types.
  • Our product is a 3 piece combination of db, web identity server, web based application. The tricky part is that this 3 piece combination is mix/match. We may deploy the db only once or twice per environment but update the web application 3 or 4 times a day and an environment may be up for a few weeks or more.

Hopefully the following drawing is slightly helpful.

So the question becomes how do we manage these scenarios? I figured from just getting started that we want each server to be a tenant? But then started to run into confusion with all the variable sets. A kick in the pants to the right direction would be most appreciated in getting our Octopus deployment off the ground.