Load balancer overview

- So the first thing you maybe wondering is, what is a load balancer? Basically it's a Azure resource, which means you can create or remove it very easily from the Azure portal or using PowerShell and what is does is it distributes inbound requests to pools of systems. So when the load balancer receives requests from the clients it will then resend those requests to the back end pool. Then the load balancer is able to check for those servers in the back end and see if they are up and running. How do load balancers work? Well, load balancers are comprised of two different sides. One is the front end and the other is the back end. The front end is usually a public IP, but it could also be a private Azure IP that could be used as a private load balancer. And then the back end which a pool of servers, app services, scale sets, that will receive the requests from the client. Then there are a set of layer four transport rules which the load balancer uses to decide to which servers those requests should be sent to. You could also add Network Address Translation rules. Letting the load balancer decide when a request is sent to a specific port, if it should be sent to one of the servers specifically in the back end. We have basic and standard load balancers depending on the workloads and their requirements and we can use TCP, HTTP and if the load balancer is a standard, HTTPS health probes to check if the back end servers are up and running or if they should be not used for traffic redirection. This is a diagram of a one-to-one communications environment. When we see clients connecting, one-to-one to different web servers. When you add a load balancer to the equation, what happens is that all the clients connect to the same load balancer and then the load balancer will decide which requests will go to each of the servers in the back end pool. And this is a very high level of review of how load balancers work in Azure.