Swapping Azure Staging/Production environments with a SignalR Hub

Question

I have a SignalR service running on an Azure Web Role. I'm interested in deploying a new version of the service, first to Staging and then to the Production deployment slot.

My question is if I swap the two deployment slots while there are existing connections to the service on Production:

What will happen to those existing connections? Will they still be connected to the now-Staging slot, or will they reconnect to the the now-Production slot? Or something else? Is this client-dependent?

Thanks!

Answer 1

It's going to depend on how you're storing SignalR connection information.

If you're using a permanent external storage solution (see this post), then swapping from one web server to another, which is what the VIP swap will end up doing, shouldn't interrupt the connections.

If you're using a different approach for storing the connection info like in-memory, then it's going to be lost b/c you're going to be transferring client traffic from one web server to another with the deployment swap.