Terraform Azure : deploy mysql network rule on another subscription

Question

I'm trying do deploy a MySQL database on Azure using Terraform (v 0.11.11). I need to set differents parts in my main.tf file:

• provider
• resource group
• mysql server
• mysql database
• mysql virtual network rule 1
• mysql virtual network rule 2
• mysql virtual network rule 3

At the moment, all those requierements work except the last one, mysql virtual network rule 3. Everything is created on subscription A but mysql virtual network rule 3 uses a subnet_id includes in subscription B.

And here is the problem, how can I write my .tf file to create a virtual network rule using a subnet_id with a subscription different from the one used until now ?

I tried to do it manually in Azure and it works. On Azure Portal, I can choose the subnet even if it based in another subscription.

#provider azurem.A is Subscription A in my text. Everything is created in this sub.
#prodiver azurem.B is Subscription B in my text. The subnet used to create vitual_network_rule_3 is in this subscription.

provider "azurerm" {
    client_id       = "${var.client_id}"
    client_secret   = "${var.client_secret}"
    tenant_id       = "${var.tenant_id}"
    subscription_id = "${var.subscription}"
    alias           = "A"
}

provider "azurerm" {
    client_id       = "${var.client_id}"
    client_secret   = "${var.client_secret}"
    tenant_id       = "${var.tenant_id}"
    subscription_id = "${var.subscription_B}"
    alias           = "B"
}

#Creating RG in Sub A.
resource "azurerm_resource_group" "rg" {
    # attributes to create RG in Sub A. works well.
    # ....
}

#Creating mysql server in Sub A.
resource "azurerm_mysql_server" "mysql_server" {
    # attributes to create mysql server. works well.
    # ....
}

#Creating mysql database in Sub A.
resource "azurerm_mysql_database" "mysql_db" {
    # attributes to create mysql database. works well.
    # ....
}

#Creating vnet rule using a subnet in Sub A. WORKING
resource "azurerm_mysql_virtual_network_rule" "mysql_vnet_1" {
    count = "${var.vnet_one != "" ? 1 : 0}"

    name                = "subscription-peering-1"
    resource_group_name = "${azurerm_resource_group.rg.name}"
    server_name         = "${azurerm_mysql_server.mysql_server.name}"
    subnet_id           = "${var.vnet_one}"
    provider = "azurerm.A"
}

#Creating vnet rule using a subnet in Sub A. WORKING
resource "azurerm_mysql_virtual_network_rule" "mysql_vnet_2" {
    count = "${var.vnet_two != "" ? 1 : 0}"

    name                = "subscription-peering-2"
    resource_group_name = "${azurerm_resource_group.rg.name}"
    server_name         = "${azurerm_mysql_server.mysql_server.name}"
    subnet_id           = "${var.vnet_two}"
    provider = "azurerm.A"
}

#Getting data to get the subnet in Subscription B in order to use it in "mysql_vnet_three".
#Uses the second provider, the one that contains Subcription B
data "azurerm_subnet" "subnet_data" {
    name                 = "my-subB-subnet-name"
    virtual_network_name = "my-subB-vnet-name"
    resource_group_name  = "my-subB-rg_name" 
    provider = "azurerm.B"
}

#Creating vnet rule using a subnet in Sub B. NOT WORKING
resource "azurerm_mysql_virtual_network_rule" "mysql_vnet_3" {
    count = "${var.vnet_exploit != "" ? 1 : 0}"

    name                = "subscription-peering-3"
    resource_group_name = "${azurerm_resource_group.rg.name}"
    server_name         = "${azurerm_mysql_server.mysql_server.name}"
    subnet_id           = "${data.azurerm_subnet.subnet_data.id}"
    provider            = "azurerm.A"
}

Thank you so much !

Answer 1

As I couldn't find the solution using TF resources, I used local-exec to run Az command in order to create the vnet rule.

resource "null_resource" "create_vnet_rule_exploit_from_cli" {
    count = "${var.vnet_exploit != "" ? 1 : 0}"

    provisioner "local-exec" {
    command = "az mysql server vnet-rule create --name subscription-peering-exploit 
        --server-name ${azurerm_mysql_server.mysql_server.name} --resource-group                                         
        ${azurerm_resource_group.rg.name} --subnet ${var.vnet_exploit} -- 
        subscription ${var.subscription}"
    }
    depends_on = ["azurerm_mysql_server.mysql_server"]
}

Answer 2

Shouldn't the provider be azurerm.B ?

#Creating vnet rule using a subnet in Sub B. NOT WORKING
resource "azurerm_mysql_virtual_network_rule" "mysql_vnet_3" {
count = "${var.vnet_exploit != "" ? 1 : 0}"

name                = "subscription-peering-3"
resource_group_name = "${azurerm_resource_group.rg.name}"
server_name         = "${azurerm_mysql_server.mysql_server.name}"
subnet_id           = "${data.azurerm_subnet.subnet_data.id}"
provider            = "azurerm.B"
}