What is the Azure Resource Manager equivalent of VIP Swap?

Question

Azure classic Cloud Services come with a built-in load balancer that allows a fast VIP swap from production to staging, and vice versa. What equivalent is provided by Azure Resource Manager? I can use DNS, but then I have the TTL delay.

I want the fast swap because my back-end servers are stateful and cannot process the same data in both staging and production without overwriting each other. In my current system, out-of-date connections (e.g. because of HTTP keep-alive) are rejected and a reload is forced, forcing fresh connections.

I guess I might be able to do it using Azure Application Gateway, but it is not listed as one of its features.

Answer 1

In Azure resource manager, there are three ways, Azure Load Balancer(layer 4), Application Gateway(layer 7) and Traffic Manager(DNS level). I think you can use Load Balancer in you scenario. The following table helps understanding the difference between Load Balancer and Application Gateway:

Answer 2

You can do VIP swap in ARM with 2 Azure load balancers by disassociating the public IPs, then reassigning them. It's not a fast deployment slot swap like you can do with cloud services however, as can take a minute to disassociate both IP addresses (you could speed this up by doing it in parallel), and based on your question you've already looked at this approach, but documenting it here as an option. There are some notes on this approach here: https://msftstack.wordpress.com/2017/02/24/vip-swap-blue-green-deployment-in-azure-resource-manager/