The azure load balancer now supports session affinity, does this mean inproc sessions are now possible or is redis cache still the only alternative?
https://azure.microsoft.com/en-gb/blog/azure-load-balancer-new-distribution-mode/
(edit). There are two aspects to this question
(1) If you have a legacy product you want to migrate that depends on inproc sessions can they be migrated
(2) 'session affinity' on the load balancer, does that help at all here
Sticky sessions (Session-affinity) for ASP.net applications are configured using State Servers. You will have to run State Service (startup task or service). If you are using web roles, it is recommended to use Azure In-Role cache. Here is the link - https://learn.microsoft.com/en-us/azure/cache/cache-dotnet-how-to-use-in-role
As David said, Radis cache is not the 'only' alternative.
Trust it helps.