Deploying Azure App Service to Multiple Subscriptions in a Tenant using Terraform and Azure DevOps - Need Advice

Question

I want to deploy and configure Azure App Service into 3 different subscriptions using Azure Terraform and Azure DevOps pipeline. Can I get some advice on how this can be done.

NOTE: For a single subscription I can make it work with out any issues.For multiple subscriptions I cannot do it.

1. I tried creating 3 different service connections

So far what I tried in VS code is:

app-deployment:
     vars.tf      - Contains all variables for all 3 different variables
     providers.tf - Contains all providers for all 3 different variables
     resources.tf - Contains terraform for creation of resource group, app service etc...
     main.yaml    - Pipeline to trigger init, validate, plan, apply

main.yaml:

trigger: none
pr: none

pool:
  vmImage: Ubuntu-latest

stages: 
- stage: deployAppService
  jobs:
  - job: to_Dev
    steps:
    - template: dev/deployTodev.yml
      parameters:
        serviceconnection: Azure-Deployment-dev
  - job: to_Acceptance
    steps:
    - template: acc/deployToacc.yml
      parameters:
        serviceconnection: Azure-Deployment-Acc
  - job: to_Production
  steps:
  - template: prod/deployToprod.yml
    parameters:
      serviceconnection: Azure-Deployment-prod

  

But I am facing issues with state files (.tfstate) as they are 3 different subscriptions.

Terraform workspaces I also read about terraform workspaces but using Terraform with Azure DevOps pipelines I am having trouble configuring , can I please get some advice on how can I do this. Thanks

Answer 1

In order to deploy terraform resources to two or more subscriptions, using multiple providers by passing alias parameter is an efficient way.

alias is used to pass the subscription name as shown below. Using that you can pass multiple subscriptions for deployment and reference it in the resource as azurerm.<aliasname>.

Refer blog by @Jeff Brown Tech for the relevant information.

Below is the complete code for your reference

provider "azurerm" {
  subscription_id = "f7bxxxxx014"
  tenant_id = "93xxxxf6d"
}
provider "azurerm" {
    alias = subscription2
    subscription_id = "subscription_id"
    tenant_id = "xxxx" //Provide tenant ID if the 2nd subscription existed in another tenant
}
provider "azurerm" {
    alias = subscription3
    subscription_id = "subscription_id"
    tenant_id = "xxxx" //Provide tenant ID if the 3rd subscription existed in another tenant
}


data "azurerm_resource_group" "example" {
  name     = "Jahnavi"
}

resource "azurerm_app_service_plan" "example" {
  provider            = "azurerm"
  name                = "examplejahserviceplan"
  location            = data.azurerm_resource_group.example.location
  resource_group_name = data.azurerm_resource_group.example.name

  sku {
    tier = "Standard"
    size = "S1"
  }
}

resource "azurerm_app_service" "example" {
  provider            = "azurerm"
  name                = "jahapservice"
  location            = data.azurerm_resource_group.example.location
  resource_group_name = data.azurerm_resource_group.example.name
  app_service_plan_id = azurerm_app_service_plan.example.id

  site_config {
    dotnet_framework_version = "v4.0"
    scm_type                 = "LocalGit"
  }

  app_settings = {}
}
resource "azurerm_app_service_plan" "example" {
  provider            = "azurerm.subscription2"
  name                = "examplejahserviceplan"
  location            = data.azurerm_resource_group.example.location
  resource_group_name = data.azurerm_resource_group.example.name

  sku {
    tier = "Standard"
    size = "S1"
  }
}

resource "azurerm_app_service" "example" {
  provider            = "azurerm.subscription2"
  name                = "jahapservice"
  location            = data.azurerm_resource_group.example.location
  resource_group_name = data.azurerm_resource_group.example.name
  app_service_plan_id = azurerm_app_service_plan.example.id

  site_config {
    dotnet_framework_version = "v4.0"
    scm_type                 = "LocalGit"
  }

  app_settings = {}
}