Load Balancer and Cross Region Load Balancer in Azure

Brass Contributor

Hello Folks !!

I am back with my new blog regarding to azure networking service . This time I will discuss about Azure Load Balancer and What is Cross region load balancing !!!



What is Load Balancer ---


Azure Load Balancer operates at layer 4 of the (OSI) model. It's the single point of contact for clients. It  distributes inbound flows that arrive at the load balancer's front end to backend instances  . These flows are according to configured load-balancing rules and health probes. 


There are generally two type of load balancer's - 

Public - which provide traffic from outbound to inbound in virtual network . 

Internal - which route traffic to internal vnet.


A Public load balancer is the one which  can provide outbound traffic  for virtual machines (VMs) inside your virtual network. These connections are accomplished by translating their private IP addresses to public IP addresses. Public Load Balancers are used to load balance internet traffic to your VMs.


An Internal load balancer is used where private IPs are needed at the frontend only. They  are used to load balance traffic inside a virtual network. A load balancer frontend can be accessed from an on-premises network in any scenario .



Why we use Azure Load Balancer - 


The main key points why we use azure load balancer are - 

  • Standard load balancer are built with zero trust network security so it is very efficient . 
  • They are part of your vnet , vnet is secured and isolated from other networks . 
  • Load Balancer services can be configured on multiple ports and IP'S .
  • You can scale your services and create highly scalable services and applications . 


Pricing - 


The main concern for every organization , whenever they there on-premise infra to cloud is pricing , so whenever its possible , I try to cover in my blog the pricing aspect of cloud services . So here we go --


Some of the key points that we need to know is - 

  • Inbound rules don't count in total number of rules , number of configured outbound and load balancing rules count.
  • There is no hourly charge for load balancer where no rules are formed 
  • The data is charged about how much inbound or outbound processing is there
  • Any traffic going through load balancer is charged . 

What is Cross region load balancing in azure - 


Cross-region Load Balancer is a Public layer-4 network load balancer serving as a single point of contact for global traffic. You can build  any regional application by setting up a Cross-region Load Balancer in front of regional deployments.


Main benefits of cross region load balancing is - 


The health probe of the cross-region load balancer gathers information about availability every 20 seconds. If one regional load balancer drops its availability to 0, cross-region load balancer will detect the failure. The regional load balancer is then taken out of rotation.


Its  algorithm is generally based on the geographic location of your users and your regional deployments.

Traffic started from a client will hit the closest participating region and travel through the Microsoft global network backbone to arrive at the closest regional deployment.


When you expose the global endpoint of a cross-region load balancer to customers, you can add or remove regional deployments behind the global endpoint without interruption.

The backend pool of cross-region load balancer contains one or more regional load balancers.

Add your existing load balancer deployments to a cross-region load balancer for a highly available, cross-region deployment.



Some of the limitations relates to it are - 

  • The internal frontend ip is not supported currently 
  • Private or internal load balancer can't be added to the backend pool .

  • A health probe can't be configured currently. 

Currently the cross region service is in preview ,and will get onboard till 2023..




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