The customer wants an "active-active" failover configured for our WebApp in their Azure Subscription. They have a private cloud, so we proposed Isolated App Server for our app. Clients to the web app are internal (on prem) and app would have no internet requirement.
When working with Isolated App Server, it seems the ILB is the only option for load balancer. We can't seem to find anywhere in the docs it indicates ILB would support another region (I think it says it does not). Since all clients are internal we cannot use Traffic Manager. We're thinking we'd need to fall back to implementing soln using VM's and not App Service. We think scale set might give us vertical scaling for said VM's? We'll then need to configure horizontal scaling by implementing VM's across regions. On top of this, we'll need to provide load balancing (they've asked for active-active). Keep in mind all clients are internal, so DNS is out. In looking at this, it would appear Application Gateway is only option?
We're looking for validation and confirmation, or a smack in the face with "here's a better way"!
At the end of the day, we're expecting to have 2 to 4 instances of the app running in multiple regions. Load Balancer between all instances. Instances would be running in seperate regrions to ensure if one region failed the app would still be available. Most likely a single app instance could support he load as it'll be somewhat static and "known" and not variable. Client counts will be static (and grow as the customer adds locations, which would be less than 50 locations per year).
Thanks for any help with this configuration conundrum!
