How to Import an Azure Load Balancer NAT Rule into Terraform

Import Azure Load Balancer NAT Rule with Terraback (recommended)

Terraback reverse-engineers your live infrastructure: it reads the Azure Load Balancer resource with read-only credentials, generates the HCL, and produces the exact import block. Two commands take you from a live Azure Load Balancer NAT Rule to managed Terraform.

terraback scan all azure --subscription-id YOUR_ID

terraback azure import --method bulk

The Terraform import block

Terraback emits a Terraform 1.5+ import block like the one below. Because the block lives in your configuration, the import is reviewable in a pull request and repeatable across environments.

import {
  to = azurerm_lb_nat_rule.ssh
  id = "/subscriptions/00000000-0000-0000-0000-000000000000/resourceGroups/prod-rg/providers/Microsoft.Network/loadBalancers/prod-lb/inboundNatRules/ssh"
}

Example azurerm_lb_nat_rule configuration

Here is a realistic Azure Load Balancer NAT Rule block. Terraback generates a fuller version from your actual resource attributes; this is a minimal, valid starting point.

resource "azurerm_lb_nat_rule" "ssh" {
  name                           = "ssh"
  resource_group_name            = "prod-rg"
  loadbalancer_id                = azurerm_lb.prod.id
  protocol                       = "Tcp"
  frontend_port                  = 2222
  backend_port                   = 22
  frontend_ip_configuration_name = "public"
}

Gotchas when importing a Azure Load Balancer NAT Rule

• The ID segment is inboundNatRules; the rule imports separately from the azurerm_lb.
• This is a single-instance NAT rule; pool-style port ranges use the separate azurerm_lb_nat_pool resource.
• frontend_ip_configuration_name must reference a configuration that exists on the load balancer.
• Unlike the other LB child resources, azurerm_lb_nat_rule also requires resource_group_name in its configuration.

Doing it manually with terraform import

The native approach is to write the azurerm_lb_nat_rule block by hand, then run terraform import azurerm_lb_nat_rule.example <import-id> for every resource, one at a time. That works for a handful of resources, but it does not scale: you author all the HCL yourself and repeat the command for each item. Terraback generates the HCL and the import blocks for your whole account in one pass.

Import other Azure resources