terraform - azure vnets by variables - terraform

Question

terraform version: v0.12.24
provider.azurerm v2.49.0
I am trying to build a vnet by having all the line items as variables and then populate them in
the variables.auto.tfvars file.
for my main.tf section:
resource "azurerm_virtual_network" "vnet" {
name = var.vnet_name
resource_group_name = var.rg_grp_name
address_space = var.vnet_cidr
location = var.region_location #match RG location
dns_servers = var.vnet_dns_servers
#tags stuff here
}
Resource "azurerm_subnet" "subnet" {
for_each = var.subnets
name = lookup(each.value, "name")
resource_group_name = var.rg_grp_name
virtual_network_name = azurerm_virtual_network.vnet.name
address_prefix = lookup(each.value, "cidr")
}
and in my variables.tf, which i am really unsure about;
###vnet section###################
#variable for defining what region
variable "name" {
type = string
}
#variable for defining what region
variable "resource_group_name" {
type = string
}
#variable for defining what region
variable "vnet_cidr" {
description = "address space"
type = list
}
#variable for defining what region
variable "region_location" {
type = string
}
#variable for defining what region
variable "vnet_dns_servers" {
type = list
}
#variable for defining what region
variable "subnets" {
type = map(object({
name = string
cidr = string
}))
}
##end subnet block
#variable for defining what region
variable "azregion" {
type = string
}
#####end vnet section#############
I dont have the variables.auto.tfvars section yet...
whats the best way to go about this?
Thanks

Answer 1

We can create the input variables by variable blocks but reference them as attributes on an object named var. We can access its value from within expressions as var.<NAME>, where <NAME> matches the label given in the declaration block.
So, according to the expressions in your main.tf file, the variable declaration block shoule be like this:
variable "vnet_name" {
description = "Name of the vnet to create"
type = string
# default = "acctvnet"
}
variable "rg_grp_name" {
description = "Name of the resource group to be imported."
type = string
# default = "testrg"
}
variable "vnet_cidr" {
type = list(string)
description = "The address space that is used by the virtual network."
# default = ["10.0.0.0/16"]
}
variable "region_location" {
type = string
# default = "eastus"
}
# If no values specified, this defaults to Azure DNS
variable "vnet_dns_servers" {
description = "The DNS servers to be used with vNet."
type = list(string)
# default = []
}
variable "subnets" {
type = map(object({
name = string
cidr = string
}))
# default = {
# subnet1 = {
# name = "subnet1"
# cidr = "10.0.1.0/24"
# },
# subnet2 = {
# name = "subnet2"
# cidr = "10.0.2.0/24"
# }
# }
}
If you would like to make terraform automatically load a number of variable definitions files, you can input the default values for that variable as the expression variable_name = default_value in the variables.auto.tfvarsfile .
vnet_name = "acctvnet"
rg_grp_name = "testrg"
vnet_cidr = ["10.0.0.0/16"]
region_location = "eastus"
vnet_dns_servers = []
subnets = {
subnet1 = {
name = "subnet1"
cidr = "10.0.1.0/24"
},
subnet2 = {
name = "subnet2"
cidr = "10.0.2.0/24"
}
}
You can check the source code in the vnet module with terraform for more details.