Features and capabilities – Configuring Load Balancing

Features and capabilities

Azure Load Balancer offers several features and capabilities as part of its service, such as load balancing, port forwarding, automatic reconfiguration, health probes, and outbound source NAT (SNAT) connections.

Load balancing

Traffic canbe distributed from a frontend pool to a backend pool using rules. Azure Load Balancer uses a five-tuple hash by default, which is composed of the source IP address, source port, destination IP address, destination ports, and the IP protocol number to map flows to the available servers in the backend pool.

Port forwarding

Inbound NAT rules can be created to forward traffic from a specific port of the frontend IP address of the load balancer to a specific port of a backend instance inside an Azure VNet. Therefore, the same hash-based distribution is used as with load balancing. This can be used for the Remote Desktop Protocol (RDP) and Secure Shell (SSH) sessions to VMs inside the VNet. Multiple internal endpoints can be mapped to various ports on the same frontend IP address. The VMs can be remotely administered using the frontend IP address. This way, an additional jump box is not needed.

Automatic reconfiguration

The load balancer will automatically reconfigure itself when instances are scaled up or down. There is no need for additional operations on the load balancer when VMs are added or removed from the backend pool.

Health probes

Azure Load Balancer uses health probes to determine the health of the VMs in the backend pool. The load balancer will stop sending new connections to a VM instance when a probe fails to respond. There are different health probes provided for HTTP, HTTPS, and TCP endpoints.

Outbound connections (SNAT)

Outbound connections are automatically translated to the public frontend IP address of the load balancer. When used on ILBs, a rule must be configured to allow outbound internet access.

Top Tip

When you configure an HTTPS health probe, you will require a certificate to perform the probe assessment.

Now that you understand some of the features and capabilities of Azure load balancers, we will explore the different stock keeping units (SKUs) available in Azure and what they differ on.