Azure VNet Subnets

Module overview

Description

Module that provisions virtual network subnets on Azure, including the following resources:

• subnet
• network security group
• security group subnet association

The number of subnets created is controlled by the number of subnet CIDR's supplied and the provision flag. If the provison flag is set to false (it is true by default), the module will not provision anything and will only read the provided subnet name details (use the subnet_name variable to supply the subnet name).

Note: This module follows the Terraform conventions regarding how provider configuration is defined within the Terraform template and passed into the module - https://www.terraform.io/docs/language/modules/develop/providers.html. The default provider configuration flows through to the module. If different configuration is required for a module, it can be explicitly passed in the providers block of the module - https://www.terraform.io/docs/language/modules/develop/providers.html#passing-providers-explicitly.

Software dependencies

The module depends on the following software components:

Command-line tools

• terraform >= v0.15 and < v1.3 Note that this module does nto support terraform version 1.3 and above

Terraform providers

• Azure provider >= 3.27.0

Module dependencies

This module makes use of the output from other modules:

• Resource Group - github.com/cloud-native-toolkit/terraform-azure-resource-group
• VNet - github.com/cloud-native-toolkit/terraform-azure-vnet

Example usage

terraform {
  required_providers {
    azurerm = {
      source  = "hashicorp/azurerm"
    }
  }
}

provider "azurerm" {
  features {}

  subscription_id = var.subscription_id
  client_id       = var.client_id
  client_secret   = var.client_secret
  tenant_id       = var.tenant_id
}

module "subnets" {
  source = "github.com/cloud-native-toolkit/terraform-azure-subnets"

  resource_group_name = module.resource_group.name
  region = var.region
  vpc_name = module.vpc.name
  ipv4_cidr_blocks = ["10.1.1.0/24", "10.1.2.0/24", "10.1.3.0/24"]
  acl_rules = [{
    name = "ssh-inbound"
    action = "Allow"
    direction = "Inbound"
    source = "*"
    destination = "*"
    tcp = {
      destination_port_range = "22"
      source_port_range = "*"
    }
  }, {
    name = "internal-only"
    action = "Allow"
    direction = "Inbound"
    source = "10.0.0.0/16"
    destination = "10.0.0.0/24"
    udp = {
      destination_port_range = "1024 - 2048"
      source_port_range = "*"
    }
  }]
}

Read Only Usage

The module may be utilised in a read-only mode by setting provision=false.

Doing so will cause the module to attempt to read an existing subnet that it is provided. Provide the resource group name, region, vnet name and subnet name in such circumstances to return the subnet details. Note that this method requires a single subnet name at a time

For example:

module "subnet-query" {
  source = "/home/richard/github/terraform-azure-subnets"

  provision           = false
  resource_group_name = module.resource_group.name
  vnet_name           = module.vnet.name
  region              = module.resource_group.region
  subnet_name         = "test-subnet"
}

Input Variables

Output Variables