Is an Internal Load Balancer zone redundant

Question

Hi,

I'm trying to work out if I create a load balancer with a private Frontend IP that has a VMSS as the backend spread across multiple availability zones.
Will the load balancer be zone redundant. Access to the Frontend IP will be from an on-prem network via VPN Gateway.

I can only find reference to load balancers with a public IP being zone redundant. But nothing that states an ILB isn't zone redundant.

Any clarification would be greatly appreciated.

Thanks,
Paul

Answer 1

Hi,

An Azure Load Balancer has two types, public and internal. Both types of load balancer support zone redundancy and zonal deployment. Both load balancer types can direct traffic across zones as needed.

Standard Load Balancer and Availability Zones
https://learn.microsoft.com/en-us/azure/load-balancer/load-balancer-standard-availability-zones

A standard load balancer supports additional abilities in regions where Availability Zones are available. These features are incremental to all standard load balancer provides. Availability Zones configurations are available for both types of Standard load balancer; public and internal. A zone-redundant frontend survives zone failure by using dedicated infrastructure in all of the zones simultaneously. Additionally, you can guarantee a frontend to a specific zone. A zonal frontend is served by dedicated infrastructure in a single zone. Cross-zone load balancing is available for the backend pool. Any virtual machine resource in a virtual network can be part of a backend pool.Basic load balancer doesn't support zones.

Reference:
https://learn.microsoft.com/en-us/azure/load-balancer/concepts#load-balancer-terminology

Best regards,
Leon