Microsoft introduced load balancing to distribute the load among a group or servers of backend resources. Azure Load Balancer is a layer 4 service in the Open Systems Interconnection model. It is the single point for clients. The load balancer can also allocate inbound flows arriving at its front end to backend pools instances.
Types of load balancers:
Public load balancer
A public load balancer is used to provide outbound connections for virtual machines within your virtual network. These connections are made by translating private IP addresses into public IP addresses. Public load balancers are used to balance internet traffic between your VMs.
Image Source: MicrosoftInternal Load Balancer
Private load balancers can be used when private IPs are needed at the frontend. Internal load balancers can be used to balance traffic within a virtual network. A load balancer frontend can also be accessed via an on-premises network or hybrid Structure.
Why use Azure Load Balancer?
Azure Load Balancingr allows you to scale your applications and create highly-available services. It supports both inbound as well as outbound scenarios. It also has low latency and high throughput. It can scale up to millions for both TCP and UDP applications.
The following are the major tasks:
First, load balancing between internal and external traffic to Azure virtual machines. Allocating resources within and between zones to increase availability.
Configuring outbound connectivity to Azure virtual machines is the second step.
Third, health probes are used to monitor load-balanced resource usage.
Fourth, support for load-balancing IPv6.
Fifth, a standard loadbalancer can provide multi-dimensional metrics via Azure Monitor. Additionally, metrics can be filtered and grouped for a particular dimension. They provide historical and current insights into the performance and health your service.
Load balance services can be used on multiple ports, multiple IP addresses or both. You can also move internal and external load balancers resources across Azure regions.
Last but not least, UDP and load-balancing TCP flow simultaneously on all ports using HA ports.
But, before you move forward, make sure to verify that Azure Load Balancingr is secure!
Is Azure Load Balancer Secure?
It is automatically secure:
The zero-trust network security model is the basis of the standard load balancer. It is however secure by default and a part of your virtual network. The virtual network is an isolated, private network.
Network Security Groups can open inbound connections to standard load balancers or public IP addresses, but they must be closed. NSGs allow traffic to be allowed directly. Traffic is not allowed to reach a resource if there is no NSG on a subnet of the resource.
The basic load balancer is also open to the internet by default. The load balancer does not store customer data.
What are the main features of Azure Load Balancer
First, you can create highly available, scalable applications by using built-in load balancing for virtual machines and cloud services. Azure Load Balancing supports TCP/UDP-based protocols.
A load balancer, for applications that require high availability and robust performance, is a second option. It automatically scales to meet increasing traffic.
Third, you can use your internal load balancer to distribute traffic among virtual machines within your private virtual networks. You can also create multi-tiered, hybrid applications.
It also helps to build highly reliable applications by using the global anycast frontend. It checks the health of your application instances. It automatically removes unhealthy instances from rotation and reinstates them when they are healthy again.
This allows you to use network address translation (NAT), which can be used to control your outbound and inbound network traffic, and protect private networks.
Last but not least, you can use load-balanced IPv6 Internet connectivity to reach native IPv6 endpoints from your Azure virtual machines. Native dual-stack endpoints, however, are used to meet regulatory requirements and address the rapidly-growing number IoT and mobile markets that are looking to connect with Azure-based services.
You can now move on to the components section. This will help you understand how Azure Load Balancer works.
Azure Load Balancer components
You can set components of Azure Load Balancingr via the Azure interface or Azure CLI, Azure PowerShell and Resource Manager Templates.
1. Configuration of Frontend IP
Your Azure Load Balancingr’s IP address is the point of contact with clients. These IP addresses can be either:
Public IP Address
Private IP Address
The nature of the IP address will determine the type of load-balancing system that is created. Private IP address selection can be used to create an internal load balancer. Public IP address selection, on the other hand is for creating an internal load balancer.
Source: Microsoft2. Backend pool
This is the list of virtual machines, or instances, that are serving the incoming request. Computing guidelines recommend that more instances be added to the backend pool to scale efficiently for high volumes of incoming traffic.
The Load balancer automatically reconfigures itself when you scale up or down instances. The load balancer will automatically reconfigure itself by adding or removing VMs to the backend pool. For optimal management, it is important to design your backend pool with the minimum number of resources.
3. Health probes
A health probe is used to determine the health status of an individual.
