Make sure terraform CLI is installed
terraformInitialize terraform Azure modules
terraform initPlan and save the infra changes into tfplan file
terraform plan -out tfplan
# Terraform used the selected providers to generate the following execution plan. Resource actions are indicated with
# the following symbols:
# + create
# Terraform will perform the following actions:
# # azurerm_resource_group.rg will be created
# + resource "azurerm_resource_group" "rg" {
# + id = (known after apply)
# + location = "westeurope"
# + name = "rg-vnet"
# }
# # azurerm_virtual_network.vnet_count[0] will be created
# + resource "azurerm_virtual_network" "vnet_count" {
# + address_space = [
# + "10.0.0.0/16",
# ]
# + dns_servers = (known after apply)
# + guid = (known after apply)
# + id = (known after apply)
# + location = "westeurope"
# + name = "vnet-c-1"
# + resource_group_name = "rg-vnet"
# + subnet = (known after apply)
# }
# # azurerm_virtual_network.vnet_count[1] will be created
# + resource "azurerm_virtual_network" "vnet_count" {
# + address_space = [
# + "10.0.0.0/16",
# ]
# + dns_servers = (known after apply)
# + guid = (known after apply)
# + id = (known after apply)
# + location = "westeurope"
# + name = "vnet-c-2"
# + resource_group_name = "rg-vnet"
# + subnet = (known after apply)
# }
# # azurerm_virtual_network.vnet_for_each["vnet-f-1"] will be created
# + resource "azurerm_virtual_network" "vnet_for_each" {
# + address_space = [
# + "10.0.0.0/16",
# ]
# + dns_servers = (known after apply)
# + guid = (known after apply)
# + id = (known after apply)
# + location = "westeurope"
# + name = "vnet-f-1"
# + resource_group_name = "rg-vnet"
# + subnet = (known after apply)
# }
# # azurerm_virtual_network.vnet_for_each["vnet-f-2"] will be created
# + resource "azurerm_virtual_network" "vnet_for_each" {
# + address_space = [
# + "10.0.0.0/16",
# ]
# + dns_servers = (known after apply)
# + guid = (known after apply)
# + id = (known after apply)
# + location = "westeurope"
# + name = "vnet-f-2"
# + resource_group_name = "rg-vnet"
# + subnet = (known after apply)
# }
# Plan: 5 to add, 0 to change, 0 to destroy.Apply the infra changes
terraform apply tfplanNow remove the vnet-c-1 and vnet-f-1 from main.tf file: ["vnet-f-2"] # ["vnet-f-1", "vnet-f-2"]
Plan and save the infra changes into tfplan file
terraform plan -out tfplan
# Terraform used the selected providers to generate the following execution plan. Resource actions are indicated with the
# following symbols:
# - destroy
# -/+ destroy and then create replacement
# Terraform will perform the following actions:
# # azurerm_virtual_network.vnet_count[0] must be replaced
# -/+ resource "azurerm_virtual_network" "vnet_count" {
# ~ dns_servers = [] -> (known after apply)
# - flow_timeout_in_minutes = 0 -> null
# ~ guid = "9fd44061-fc5b-4c3e-8ebb-fdd0d1cd9aba" -> (known after apply)
# ~ id = "/subscriptions/82f6d75e-85f4-434a-ab74-5dddd9fa8910/resourceGroups/rg-vnet/providers/Microsoft.Network/virtualNetworks/vnet-c-1" -> (known after apply)
# ~ name = "vnet-c-1" -> "vnet-c-2" # forces replacement
# ~ subnet = [] -> (known after apply)
# - tags = {} -> null
# # (3 unchanged attributes hidden)
# }
# # azurerm_virtual_network.vnet_count[1] will be destroyed
# # (because index [1] is out of range for count)
# - resource "azurerm_virtual_network" "vnet_count" {
# - address_space = [
# - "10.0.0.0/16",
# ] -> null
# - dns_servers = [] -> null
# - flow_timeout_in_minutes = 0 -> null
# - guid = "34dbb121-0d30-4745-9159-19e531bf584e" -> null
# - id = "/subscriptions/82f6d75e-85f4-434a-ab74-5dddd9fa8910/resourceGroups/rg-vnet/providers/Microsoft.Network/virtualNetworks/vnet-c-2" -> null
# - location = "westeurope" -> null
# - name = "vnet-c-2" -> null
# - resource_group_name = "rg-vnet" -> null
# - subnet = [] -> null
# - tags = {} -> null
# }
# # azurerm_virtual_network.vnet_for_each["vnet-f-1"] will be destroyed
# # (because key ["vnet-f-1"] is not in for_each map)
# - resource "azurerm_virtual_network" "vnet_for_each" {
# - address_space = [
# - "10.0.0.0/16",
# ] -> null
# - dns_servers = [] -> null
# - flow_timeout_in_minutes = 0 -> null
# - guid = "b03988e2-1ab9-4577-a165-0f12afeabefb" -> null
# - id = "/subscriptions/82f6d75e-85f4-434a-ab74-5dddd9fa8910/resourceGroups/rg-vnet/providers/Microsoft.Network/virtualNetworks/vnet-f-1" -> null
# - location = "westeurope" -> null
# - name = "vnet-f-1" -> null
# - resource_group_name = "rg-vnet" -> null
# - subnet = [] -> null
# - tags = {} -> null
# }
# Plan: 1 to add, 0 to change, 3 to destroy.Now note the changes that will be made: vnet-c-1 and vnet-f-1 will be destroyed, that ius expected however, vnet-c-2 will be also deleted and recreated, that is not expected ! The learning here is that count will try to always start with zero index and will not try to preserve the existing resources.
Delete the infra
terraform destroyMore resources:
Terraform count doc:
https://developer.hashicorp.com/terraform/language/meta-arguments/count
Terraform for_each doc:
https://developer.hashicorp.com/terraform/language/meta-arguments/for_each