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azureazure-virtual-networkazure-application-gatewayazure-load-balancer

When to use Azure Network interfaces' application_gateway_backend_address_pools

I went through Azure documentation on Application gateway & network interfaces but couldn't find information about when to use application_gateway_backend_address_pools

I have a usecase where I have a VM added as a backend pool for App gateway, as a virtual machine.

Though application_gateway_backend_address_pools is not added to NIC, I'm able to access the service hosted in VM through gateway. Do I need to still add define application_gateway_backend_address_pools in VM's NIC ?

Similarly, when do we use load_balancer_backend_address_pools ?

Az documentation references: nic-sdk-info / app-gateway-components / nic

Solution

  • You don't need to define application_gateway_backend_address_pools or load_balancer_backend_address_pools in the NIC properties if you're already managing these associations through the respective Load Balancer or Application Gateway configurations.

    Reason- In Azure, Network Interface Cards (NICs) are associated with Virtual Machines (VMs) and can be connected to different networking resources, including Load Balancers and Application Gateways. The backend pools for both Load Balancers and Application Gateways are typically managed directly through those services, rather than through individual NIC configurations.

    When writing ARM templates, these properties are available if you need to establish the association between NICs and backend pools at deployment time. In many ARM templates, you'll see these properties used because ARM templates are often designed to set up all necessary associations and configurations in one go. Would recommend for ARM template to define the VMs separately and define the Load Balancer/App gateway with backend separately.

    Reference-

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