CODEWITHSUNDEEP
terraformterraform-provider-azure
Geordie
Geordie

Reputation: 2184

Getting Terraform resource already exists error with resource just created by Terraform

I'm setting up a virtual network in Azure with Terraform.

I have several VNets each with their own Network Security Group 100% managed in Terraform, no resources except the Resource Group exist prior to running Terraform.

When I run Terraform apply the first time all the resources are created correctly. However if I try and run apply again to update other resources I get an error saying the NSG resources already exist.

Error: A resource with the ID
"/subscriptions/0000000000000000/resourceGroups/SynthArtInfra/providers/Microsoft.Network/networkSecurityGroups/SynthArtInfra_ServerPoolNSG"
already exists - to be managed via Terraform this resource needs to be
imported into the State. Please see the resource documentation for
"azurerm_network_security_group" for more information.

Why is Terraform complaining about an existing resource when it should already be under it's control?

Edit: This is the code related to the NSG, everything else is to do with a VPN gatway:

# Configure the Azure provider
terraform {
  required_providers {
    azurerm = {
      source = "hashicorp/azurerm"
      version = ">= 2.26"
    }
  }
}

provider "azurerm" {
  features {}
}

data "azurerm_resource_group" "SynthArtInfra" {
    name     = "SynthArtInfra"
    location = "Somewhere" # not real
    most_recent = true
}


resource "azurerm_virtual_network" "SynthArtInfra_ComputePool" {
  name = "SynthArtInfra_ComputePool"
  location = azurerm_resource_group.SynthArtInfra.location
  resource_group_name = azurerm_resource_group.SynthArtInfra.name
  address_space = ["10.6.0.0/16"]
}

resource "azurerm_subnet" "ComputePool_default" {
  name = "ComputePool_default"
  resource_group_name = azurerm_resource_group.SynthArtInfra.name
  virtual_network_name = azurerm_virtual_network.SynthArtInfra_ComputePool.name
  address_prefixes = ["10.6.0.0/24"]
}


resource "azurerm_network_security_group" "SynthArtInfra_ComputePoolNSG" {
  name                = "SynthArtInfra_ComputePoolNSG"
  location            = azurerm_resource_group.SynthArtInfra.location
  resource_group_name = azurerm_resource_group.SynthArtInfra.name

  security_rule {
    name                       = "CustomSSH"
    priority                   = 119
    direction                  = "Inbound"
    access                     = "Allow"
    protocol                   = "*"
    source_port_range          = "*"
    destination_port_range     = "0000" # not the real port number
    source_address_prefix      = "*"
    destination_address_prefix = "*"
  }    
   
}

The other odd thing is our subscription has a security policy that automatically adds NSGs to resources that don't have one. But weirdly after applying my terraform script the NSGs are created but aren't actually associated with the Subnets and the security policy has created new NSGs. This needs to be resolved but didn't think it would cause this error.

Upvotes: 8

Views: 13756

Answers (2)

Jaak
Jaak

Reputation: 11

TLDR; Try removing any custom dependencies between resources that you have added yourself.

Hi, I came across this post whilst having a similar problem and will put my solution here in case that helps someone else.

I was working on creating a Cloud Run Service through Terraform. The first time went great and it created the resource I wanted, but as soon as I ran the apply again I would get this error saying that a resource with that name already exists. This was strange because according to the plan it was supposed to delete and then replace that resource.

What happened was that I added an uneccessary depends_on field on a few other resources and this was blocking the Cloud Run Service resource from being deleted before trying to create a new one.

According to the docs the depends_on field is only needed if there is some strange dependency that cannot be inferred by looking at the fields. So I just removed all of the custom ties between the dependencies and can now re-apply as much as I like.

Upvotes: 1

Geordie
Geordie

Reputation: 2184

I think what was going on is this is my first time using Terraform so I was getting a lot of errors midway through apply and destroy operations.

I ended up manually removing all the resources in Azure and deleting Terraform's local cache then everything started working.

Upvotes: 1

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