Azure load balancer inside a subnet

Question

I have a VNET with a subnet, there are 3 VMs in the subnet, the VNET is connected via a VPN connection to an on-premises server. The on-premises server will send requests to an internal IP of the subnet.

What I'd like to do is host a load balancer with no public IP, but has an IP in the subnet range. The on-premises app would then talk to the single load balancer, which would in turn forward the request on to any of the servers hosting my app in the subnet.

Can anyone tell me if this is possible, or an alternative if possible.

Answer 1

I believe you are looking for an internal load balancer. You can find documentation for that here: https://docs.microsoft.com/en-us/azure/load-balancer/load-balancer-get-started-ilb-arm-portal.

Azure Internal Load Balancer (ILB) provides network load balancing between virtual machines that reside inside a cloud service or a virtual network with a regional scope.

Create a Load Balancer as usual, but specify Type: Internal. Probably best to make it use a static IP address as well so it won't change. Then you'll need to configure its back-end pool and health probe so it knows where to route traffic.