I was trying to test the scenario of handling external changes to existing resources and then syncing my HCL config to the current state in the next apply. I could achieve that using 'taint' for the modified resource, but TF deleted other resources which were deployed during the first 'apply'. Here is the module code for a VNet with 3 subnets(prod,dmz and app) and 3 NSGs associated. And I tested with modifying one of the NSGs but TF deleted all of the subnets-
VNET-
resource "azurerm_virtual_network" "BP-VNet" {
name = var.Vnetname
location = var.location
resource_group_name = var.rgname
address_space = var.vnetaddress
subnet {
name = "GatewaySubnet"
address_prefix = "10.0.10.0/27"
}
}
Subnet -
resource "azurerm_subnet" "subnets" {
count = var.subnetcount
name = "snet-prod-${lookup(var.snettype, count.index, "default")}-001"
address_prefixes = ["10.0.${count.index+1}.0/24"]
resource_group_name = var.rgname
virtual_network_name = azurerm_virtual_network.BP-VNet.name
}
NSGs-
resource "azurerm_network_security_group" "nsgs" {
count = var.subnetcount
name = "nsg-prod-${lookup(var.snettype, count.index, "default")}"
resource_group_name = var.rgname
location = var.location
--------
}
BastionSubnet-
resource "azurerm_subnet" "bastionsubnet" {
name = "AzureBastionSubnet"
virtual_network_name = azurerm_virtual_network.BP-VNet.name
resource_group_name = var.rgname
address_prefixes = [ "10.0.5.0/27" ]
}
The end result of second apply is -
With just Gateway subnet. It should not have deleted rest of the 4 subnets. Why is this happening?
The solution may confuse you. You can separate the GatewaySubnet from the azurerm_virtual_network block into an azurerm_subnet block. The code looks like this:
resource "azurerm_subnet" "gateway" {
name = "GatewaySubnet"
resource_group_name = var.rgname
virtual_network_name = azurerm_virtual_network.BP-VNet.name
address_prefixes = ["10.0.10.0/27"]
}
I don't know the certain reason, but it solves your issue.
Related
Im trying to get value from one module and use it in another module.
I have module - vnet
resource "azurerm_virtual_network" "vnet" {
name = var.vnet_name
resource_group_name = var.resource_group_name
location = var.location
address_space = var.address_space
}
resource "azurerm_subnet" "subnet" {
name = "${var.vnet_name}-subnet"
resource_group_name = var.resource_group_name
virtual_network_name = azurerm_virtual_network.vnet.name
address_prefixes = var.subnet_prefixes
}
and the output is :
output "subnet_id" {
value = "${azurerm_subnet.subnet.id}"
}
output "vnet_name" {
value = "${azurerm_virtual_network.vnet.name}"
}
from this module i would like to get the vnet name and the subnet id for my other module that im using to create a nic.
nic module
module "vnet" {
source = "../vnet"
}
resource "azurerm_network_interface" "nic" {
name = "${module.vnet.vnet_name}-nic"
location = "east us 2"
resource_group_name = "null"
ip_configuration {
name = " "
subnet_id = module.vnet.subnet_id
private_ip_address_allocation = "Dynamic"
}
}
this way is working BUT the terraform plan , planning to create 2 resource per each resource because the way im using to get the values .
under nic module im using again the vnet module so its will create second vnet.
my main.tf is
resource "azurerm_resource_group" "rg" {
name = var.resource_group.name
location = var.resource_group.location
}
module "ib151w-vnet" {
source = "./modules/vnet"
resource_group_name = azurerm_resource_group.rg.name
vnet_name = "ib151w-vnet"
address_space = var.address_space
subnet_prefixes = var.subnet_prefixes
}
module "ib151w-nic" {
source = "./modules/nic"
name = "nic-test-123"
location = "east us 2"
resource_group_name = "ib151w"
}
the question is how can i get the vnet name and subnet id to use inside the nic module ?
i know there is alot of better ways to establish my request but im
just learning terraform and trying this specific way :)
how can i get the vnet name and subnet id to use inside the nic module
You have to explicitly pass those values in the root module:
module "ib151w-nic" {
source = "./modules/nic"
name = "nic-test-123"
location = "east us 2"
resource_group_name = "ib151w"
vnet_name = module.vnet.vnet_name
subnet_id = module.vnet.subnet_id
}
Also you have to modify your vnet module to make vnets and subents conditional. For example, add variable in the vent module:
variable "should_create_vnet_and_subnet" {
default = true
}
then make the resource conditional:
resource "azurerm_virtual_network" "vnet" {
count = should_create_vnet_and_subnet == true ? 1 : 0
name = var.vnet_name
resource_group_name = var.resource_group_name
location = var.location
address_space = var.address_space
}
resource "azurerm_subnet" "subnet" {
count = should_create_vnet_and_subnet == true ? 1 : 0
name = "${var.vnet_name}-subnet"
resource_group_name = var.resource_group_name
virtual_network_name = azurerm_virtual_network.vnet.name
address_prefixes = var.subnet_prefixes
}
And the rest. Basically you have to rewrite your entire vnet module around conditional resources.
There are a lot of things to reconsider here but I would like to stick to your query only as you have requested.
How to get value from the module in another module - Terraform
As I can see you are already using two modules for vnet(which includes subnet) and nic and also using two modules interface calls to use them. You can simply use variables in your nic module and then at the interface level you can pass the outputs from vnet module as an attribute to your nic module.
Refer to the below code.
# main.tf or MODULE INTERFACES
## Default variables ##
variable "resource_group_name" {
type = string
description = "(optional) resource group name in which resources will created"
default = "stack-over-flow-query"
}
variable "location" {
type = string
description = "(optional) location where resources would be created."
default = "east us 2"
}
################################
resource "azurerm_resource_group" "rg" {
name = var.resource_group_name
location = var.location
}
module "ib151w-vnet" {
source = "./modules/vnet"
resource_group_name = azurerm_resource_group.rg.name
location = azurerm_resource_group.rg.location
vnet_name = "ib151w-vnet"
address_space = ["10.0.0.0/16"]
subnet_prefixes = ["10.0.1.0/24"]
}
module "ib151w-nic" {
source = "./modules/nic"
name = "${module.ib151w-vnet.vnet_name}-nic-test-123"
location = azurerm_resource_group.rg.location
resource_group_name = azurerm_resource_group.rg.name
subnet_id = module.ib151w-vnet.subnet_id
ip_configuration = "stackoverflow"
}
## NIC Module
resource "azurerm_network_interface" "nic" {
name = var.name
location = var.location
resource_group_name = var.resource_group_name
ip_configuration {
name = var.ip_configuration
subnet_id = var.subnet_id
private_ip_address_allocation = var.private_ip_address_allocation
}
}
## Required variable definitions with defaults(best practice installation in your situation)
Using the same outputs as yours in the vnet module.
output "vnet_name" {
value = azurerm_virtual_network.vnet.name
}
output "subnet_id" {
value = azurerm_subnet.subnet.id
}
Note: "${}"aka interpolation is not required when using terraform referencing without variables or any unknown value to terraform.
There can be a lot more ways to have a module like this but I would suggest at least a few things to try and do hands-on.
Use looping in your module to make multiple resources with one interface call [ only when necessary and make sense ]
https://developer.hashicorp.com/terraform/tutorials/configuration-language/for-each
Warning: extra looping can increase complexity.
Use conditions to control your module behavior.
https://developer.hashicorp.com/terraform/language/expressions/conditionals
And the most important when to use a module.
https://developer.hashicorp.com/terraform/language/modules/develop#when-to-write-a-module
I hope this helps and as I have stated this only answers your query, not some best practices or best vnet-nic module.
I have a pipeline that downloads standard Terraform modules and creates resources.
"Module-ResourceGroup" deploys resource group.
"Module-Vnet" which deploys vnet.
"Module-Subnet" which deploys subnets.
My problem is when I kick the pipeline for the first time my pipeline fails reason because Module-Subnet gives me an error message that Vnet does not exist.
However, when I run the same pipeline for a second time, my Subnets get deployed without any issues as during the first run, then Vnet gets created.
I guess I have two solutions :
depends_on where I can say that by subnet module is dependent on vnet module.
Introduce a wait of 3 mins in the subnet module before it gets executed.
Q1. why it is happening? whereas as per terraform "Most of the time, Terraform infers dependencies between resources based on the configuration given" https://learn.hashicorp.com/tutorials/terraform/dependencies
if anything is wrong with the way I have written modules?
Q2. What is a better solution depends_on OR introduce wait
Q3. Is there any other way to fix it?
Below are my modules.
Module-ResourceGroup/main.tf
resource "azurerm_resource_group" "my-resourcegroup" {
name = format("%s-%s",var.resource_group_name,var.env)
location = var.location
}
Module-Vnet/main.tf
resource "azurerm_virtual_network" "my-vnet" {
name = format("%s-%s",var.vnet_name,var.env)
resource_group_name = format("%s-%s",var.resource_group_name,var.env)
location = var.location
address_space = var.address_space
}
Module-Subnet/main.tf
resource "azurerm_subnet" "my-subnet" {
for_each = var.subnetsconfig
name = format("%s-%s",each.key,var.env)
address_prefixes = each.value["address_prefixes"]
virtual_network_name = format("%s-%s",var.vnet_name,var.env)
resource_group_name = format("%s-%s",var.resource_group_name,var.env)
}
If you use the output of a resource as the input of another resource then Terraform will understand it as an implicit dependency. For example (as you did not post all of your code):
Module-ResourceGroup/main.tf
resource "azurerm_resource_group" "my-resourcegroup" {
name = format("%s-%s",var.resource_group_name,var.env)
location = var.location
}
Module-Vnet/main.tf
resource "azurerm_virtual_network" "my-vnet" {
name = format("%s-%s",var.vnet_name,var.env)
resource_group_name = azurerm_resource_group.my-resourcegroup.name
location = var.location
address_space = var.address_space
}
Module-Subnet/main.tf
resource "azurerm_subnet" "my-subnet" {
for_each = var.subnetsconfig
name = format("%s-%s",each.key,var.env)
address_prefixes = each.value["address_prefixes"]
virtual_network_name = azurerm_virtual_network.my-vnet.name
resource_group_name = azurerm_resource_group.my-resourcegroup.name
}
I keep getting this weird error according to me, is there a fix for this.
data "azurerm_resource_group" "rg" {
name = var.resource_group_name
#environment = var.environment
}
resource "azurerm_virtual_network" "vnet" {
name = var.vnet_name
location = var.location
resource_group_name = var.resource_group_name
address_space = var.address_space
}
resource "azurerm_subnet" "subnet" {
name = var.subnet_name
resource_group_name = var.resource_group_name
virtual_network_name = var.vnet_name
address_prefixes = ["10.0.0.0/24"]
service_endpoints = ["Microsoft.Sql"]
delegation {
name = "delegation"
service_delegation {
name = "Microsoft.ContainerInstance/containerGroups"
actions = ["Microsoft.Network/virtualNetworks/subnets/join/action", "Microsoft.Network/virtualNetworks/subnets/prepareNetworkPolicies/action"]
}
}
}
I keep getting this error
azurerm_subnet.subnet: Creating...
azurerm_virtual_network.vnet: Creating...
azurerm_virtual_network.vnet: Creation complete after 5s [id=/subscriptions/e4da9536-6759-4506-b0cf-10c70facd033/resourceGroups/rg-sagar/providers/Microsoft.Network/virtualNetworks/vnet]
╷
│ Error: creating Subnet: (Name "subnet" / Virtual Network Name "vnet" / Resource Group "rg-sagar"): network.SubnetsClient#CreateOrUpdate: Failure sending request: StatusCode=404 -- Original Error: Code="ResourceNotFound" Message="The Resource 'Microsoft.Network/virtualNetworks/vnet' under resource group 'rg-sagar' was not found. For more details please
go to https://aka.ms/ARMResourceNotFoundFix"│
│ with azurerm_subnet.subnet,
│ on main.tf line 14, in resource "azurerm_subnet" "subnet":
│ 14: resource "azurerm_subnet" "subnet" {
│
Even after the vnet is created, it is unable to create a vnet, any idea how I can make this work
Any idea how to fix this?
You need to use this statement virtual_network_name = azurerm_virtual_network.vnet.name instead of virtual_network_name = var.vnet_name.
Becuause virtual_network_name = var.vnet_name in subnet resource block simultaneously creating subnet and vnet so this is not good fit in azure. Because subnet dependent on Vnet. So Vnet Should create first. So you need to use virtual_network_name = azurerm_virtual_network.vnet.name for using the existing Vnet.
Terraform Code
provider "azurerm" {
features{}
}
data "azurerm_resource_group" "rg" {
name = var.resource_group_name
#environment = var.environment
}
resource "azurerm_virtual_network" "vnet" {
name = var.vnet_name
location = data.azurerm_resource_group.rg.location
resource_group_name = var.resource_group_name
address_space = var.address_space
}
resource "azurerm_subnet" "subnet"{
name = var.subnet_name
resource_group_name = var.resource_group_name
virtual_network_name = azurerm_virtual_network.vnet.name
address_prefixes = ["10.0.0.0/24"]
service_endpoints = ["Microsoft.Sql"]
delegation {
name = "delegation"
service_delegation {
name = "Microsoft.ContainerInstance/containerGroups"
actions = ["Microsoft.Network/virtualNetworks/subnets/join/action", "Microsoft.Network/virtualNetworks/subnets/prepareNetworkPolicies/action"]
}
}
}
I think this question requires a bit more explanation, since there is nothing wrong with the code. Terraform is trying to be smart about the way it creates resources, so it tries to create as much as it can in one run. This is why there is an option called -parallelism:
-parallelism=n Limit the number of parallel resource operations.
Defaults to 10.
This means that when running terraform apply, Terraform will try to run 10 resource operations including resource creation. In your case, it will try to create both the vnet and the subnet resource (parallelism applies in apply, plan and destroy). However, since you are using the same variable in both resources (var.vnet_name), Terraform is not aware that there are dependencies between the two. The way you have structured your code now would work if you were to create the vnet first and add the subnet resource after the vnet is created. Or if you are feeling adventurous you could set the parallelism to 1. Since you probably do not want that, the best way to tell Terraform in which order to create stuff is by using resource dependencies. Terraform has a concept of implicit [1] and explicit [2] dependencies. Dependencies help Terraform decide what needs to be created, based on the graph it creates [3].
There are two options in your case:
Create an implicit dependency between vnet and subnet
Create an explicit dependency between vnet and subnet
As using depends_on (or explicit dependency) is advised only in cases where there is not another way to tell Terraform that two resources are interdependent, the best way to do it is by using the implicit dependency:
data "azurerm_resource_group" "rg" {
name = var.resource_group_name
}
resource "azurerm_virtual_network" "vnet" {
name = var.vnet_name
location = var.location
resource_group_name = var.resource_group_name
address_space = var.address_space
}
resource "azurerm_subnet" "subnet" {
name = var.subnet_name
resource_group_name = var.resource_group_name
virtual_network_name = azurerm_virtual_network.vnet.name # <-- implicit dependency
address_prefixes = ["10.0.0.0/24"]
service_endpoints = ["Microsoft.Sql"]
delegation {
name = "delegation"
service_delegation {
name = "Microsoft.ContainerInstance/containerGroups"
actions = ["Microsoft.Network/virtualNetworks/subnets/join/action", "Microsoft.Network/virtualNetworks/subnets/prepareNetworkPolicies/action"]
}
}
}
The vnet resource exports some attributes after it is created [4], including the name attribute. This helps with creating the implicit dependency: by referencing a resource and one of the attributes that is available after the resource is created, you are telling Terraform that it first needs to create the vnet and only after it is available it can start with subnet creation.
[1] https://www.terraform.io/language/resources/behavior#resource-dependencies
[2] https://www.terraform.io/language/meta-arguments/depends_on
[3] https://www.terraform.io/internals/graph#resource-graph
[4] https://registry.terraform.io/providers/hashicorp/azurerm/latest/docs/resources/virtual_network#attributes-reference
In my main terraform file I have:
resource "azurerm_resource_group" "rg" {
name = var.rg_name
location = var.location
}
resource "azurerm_public_ip" "public_ip" {
name = "PublicIP"
location = azurerm_resource_group.rg.location
resource_group_name = azurerm_resource_group.rg.name
domain_name_label = var.domain_name_label
allocation_method = "Dynamic"
}
And in my outputs file I have:
data "azurerm_public_ip" "public_ip" {
name = "PublicIP"
resource_group_name = azurerm_resource_group.rg.name
depends_on = [azurerm_resource_group.rg, azurerm_public_ip.public_ip]
}
output "public_ip" {
value = data.azurerm_public_ip.public_ip.ip_address
}
All the resources including IP get created, however the output is blank. How can I fix this?
Make sure output.tf contains only output tags and main.tf contains resources tags
The following works just fine for me:
Main.tf
resource "azurerm_resource_group" "example" {
name = "resourceGroup1"
location = "West US"
}
resource "azurerm_public_ip" "example" {
name = "acceptanceTestPublicIp1"
resource_group_name = azurerm_resource_group.example.name
location = azurerm_resource_group.example.location
allocation_method = "Static"
tags = {
environment = "Production"
}
}
Output.tf
output "azurerm_public_ip" {
value = azurerm_public_ip.example.ip_address
}
In case you want to have a dependency between resources, use depends_on inside the resource tag.
For example:
depends_on = [azurerm_resource_group.example]
Steps to reproduce:
terraform init
terraform plan
terraform apply
terraform output
Update-
The reason you get blank public IP is since declaring allocation_method = "Dynamic"
From the docs:
Note Dynamic - Public IP Addresses aren't allocated until they're assigned to a
resource (such as a Virtual Machine or a Load Balancer) by design
within Azure.
Full working example with dynamic allocation.
I had the same issue. The actual problem seems to be the dynamic allocation. The IP address is not known until it is actually used by a VM.
In my case, I could solve the issue by adding the VM (azurerm_linux_virtual_machine.testvm) to the depends_on list in the data source:
data "azurerm_public_ip" "public_ip" {
name = "PublicIP"
resource_group_name = azurerm_resource_group.rg.name
depends_on = [ azurerm_public_ip.public_ip, azurerm_linux_virtual_machine.testvm ]
}
Unfortunately, this seems not to be documented in https://www.terraform.io/docs/providers/azurerm/d/public_ip.html
I'm trying to create network Interface in Azure through terraform using below script :
resource "azurerm_subnet" "internal" {
name = "Subnet1"
resource_group_name = "${var.VNetResourceGroup}"
virtual_network_name = "${var.VNetName}"
address_prefix = "10.0.2.0/24"
}
resource "azurerm_network_interface" "main" {
name = "${var.prefix}-nic"
location = "${var.location}"
resource_group_name = "${var.resourceGroup}"
ip_configuration {
name = "ipconfig1"
subnet_id = "${azurerm_subnet.internal.id}"
private_ip_address_allocation = "dynamic"
}
}
This script creates the Subnet Subnet1 and assigning that Subnet.id in ipconfiguration.
But if I have to create another network interface again through another .tf file with the same Subnet1 , how to do I get the ${azurerm_subnet.internal.id} value again.
That is if the Subnet is already existing and I do not want to create it, how to I set those values and use them?
EDIT
I have figured out, in powershell this is the script used to determine Subnet id :
$vnetId= "[resourceId("VNetRG",'Microsoft.Network/virtualNetworks', "VNetName")]"
$subnetRef = "[concat($vnetId, '/subnets/', "Subnet1")]"
where VNetRG - resource group of VNet ,
VNetName - Name of VNet ,
Subnet1 - Name of Subnet.
Can anyone tell me what is the equivalent script in terraform?
Use a subnet data source:
data "azurerm_subnet" "subnet1" {
name = "Subnet1"
virtual_network_name = "${var.VNetName}"
resource_group_name = "${var.VNetResourceGroup}"
}
Then reference it in your NIC code with
subnet_id = "${data.azurerm_subnet.subnet1.id}"