Azure Load Balancer

Hi Guys today we are going to understand about Azure load balancer. So, what is load balancer before that let’s know about the term called “Load Balancing” which is the efficient way of distribution of the incoming network or application traffic across the multiple servers in a server farm.

What is Load Balancer?

Load Balancer is a device which is set up in the Azure infrastructure which works on the layer-4 of the OSI model (Open Systems Interconnection) that provides distributing the traffic evenly among the healthy Virtual machines which are built for the taking the traffic. You can create scale up your application and create high availability for your services. For example, as per assumption consider Amazon the famous shopping website so in normal days the number persons visiting the site so each time a person visits while logging in the user session creates a request to the amazon server So normally approximately 3 million people across the world login the amazon site but during any sale is put on the site number of people logging increases drastically around 1 billion so in order to manage the incoming traffic the load balancer is used so that there is minimal chance of the application server to crash. In case there any server goes down load balancer will manage to route it to other one.

So, the above diagram is a simple representation of how the load balance is set-up. We are visiting a shopping website which hits the request through HTTP port number 80  as the website uses https://abc.com (for example) and traffic is distributed among the Virtual machines to take forward the request.  Each website consists of a web server which is responsible to host the web pages and URL that you visit in your laptop or mobile.

Types of Load Balancers: 

Basically there are five types of load balancers, they are:

1. Public load balancer
2. Internal or Private load balancer
3. Port based forwarding load balancer
4. Outbound connectivity

Public Load Balancer: This helps in managing the incoming internet traffic to the virtual machines.

Internal or Private load balancer : This helps in managing the traffic inside a Virtual Network.

Port based forwarding load balancer : This forwards traffic to a specific port on a specific VM.

Outbound connectivity: This manages the outbound traffic A Virtual Machine that is part of the backend pool of a Standard (not Basic) Internal Load Balancer cannot make outgoing connections to the Internet.To make outgoing connections it is necessary to create a second Load Balancer with a public IP with the same backend pool and a dummy rule with a dummy probe. Once the rule is created then it will trigger the creation of an outbound SNAT.

Generally, the load balancer uses the Five-tuple hash algorithm which are set of five different values that comprise a Transmission Control Protocol/Internet Protocol (TCP/IP) connection. It helps in distribution of inbound flow and rewrites the headers of flow to the backend pool instances accordingly.   The Five-tuple hash are which are checked by the load balancer based on the type used.

·       Source IP address

·       Source port

·       Destination IP address

·       Destination port

·       IP protocol number to map flows to available servers

Stock Keeping Units (SKU’s):

In general , SKU’s are an item which is on sale as a package while using a load balancers. These are like further enhancements that can be done on the load balancer. Basically azure provide two types of SKU’s

1.     Standard SKU’s

2.     Basic SKU’s

 So, hope this blog will help you to understand the Azure Load Balancers and its features. If you enjoyed this post, I’d be very grateful if you’d help it spread by emailing it to a friend, or sharing it on Twitter or Facebook. Thank you!