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Pass terraform provider variables as secrets

Many times you need to provide values in provider information when using terraform. Lets take as an example the below code block. The azuredevops provider needs some variables in order to deploy successfully and we need to pass those values as secrets because they contain sensitive information.

terraform {
required_providers {
azuredevops = {
source = "microsoft/azuredevops"
version = ">=1.0.0"
}
}
}

provider "azuredevops" {
org_service_url = URL
personal_access_token = TOKEN
}

We should never hardcode such information in the application as this information may get leaked. In order to pass those as secrets we will need to create a variable group or standalone variables and place the secrets there.

Then we will need to create some terraform variables and pass the values for those through the pipeline.

variable "org_service_url" {
description = "The URL of your Azure DevOps organization."
}

variable "personal_access_token" {
description = "The personal access token for authentication."
}

The provider block should be updated accordingly.

provider "azuredevops" {
org_service_url = var.org_service_url
personal_access_token = var.personal_access_token
}

Finally we pass those values through the pipeline step by providing those with -var argument on terraform.

    - task: TerraformTaskV4@4
displayName: terraform apply
inputs:
provider: 'azurerm'
command: 'apply'
workingDirectory: '$(System.DefaultWorkingDirectory)/src/iac_devops'
commandOptions: '-var="org_service_url=$(URL)" -var="personal_access_token=$(PAT)"'
environmentServiceNameAzureRM: 'SUBSCRIPTION'

Finally the pipeline will succeed.

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Azure DevOps Terraform Provider

If you work everywhere as a code you will probably need to check Azure DevOps terraform provider. It is created and maintained from Microsoft and you can use it in order to have your DevOps tool as a code.

https://registry.terraform.io/providers/microsoft/azuredevops/latest/docs

In order to getting started you will need to create a PAT token and give it the access based on the actions that you need to do.

When the token is ready you will need to set two environmental variables on the machine that you work. The first one is AZDO_PERSONAL_ACCESS_TOKEN which should be your token. The second one will be your org URL AZDO_ORG_SERVICE_URL

export AZDO_PERSONAL_ACCESS_TOKEN= TOKEN
export AZDO_ORG_SERVICE_URL= https://dev.azure.com/geralexgr

Finally you are ready to deploy your IAC Azure DevOps configurations.

Lets see the below example.

# Make sure to set the following environment variables:
#   AZDO_PERSONAL_ACCESS_TOKEN
#   AZDO_ORG_SERVICE_URL
terraform {
  required_providers {
    azuredevops = {
      source = "microsoft/azuredevops"
      version = ">=0.1.0"
    }
  }
}

resource "azuredevops_project" "project" {
  name = "My Awesome Project"
  description  = "All of my awesomee things"
}

resource "azuredevops_git_repository" "repository" {
  project_id = azuredevops_project.project.id
  name       = "My Awesome Repo"
  initialization {
    init_type = "Clean"
  }
}

resource "azuredevops_build_definition" "build_definition" {
  project_id = azuredevops_project.project.id
  name       = "My Awesome Build Pipeline"
  path       = "\\"

  repository {
    repo_type   = "TfsGit"
    repo_id     = azuredevops_git_repository.repository.id
    branch_name = azuredevops_git_repository.repository.default_branch
    yml_path    = "azure-pipelines.yml"
  }
}

When above code runs it will create a new project with the name My Awesome Project. Inside the project a new git repo will be initialized and a new pipeline will be created inside this repository.

You can find the usage example below.

https://github.com/microsoft/terraform-provider-azuredevops

Youtube video:

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Access Managed Identity from container inside VM – Azure

Managed identity is the best practice regarding security when accessing resources on Azure. There are many ways you can use it for service to service communication. Sometimes though you can use nested managed identity in more complex scenarios like the one demonstrated below. In this guide we will enable managed identity on a virtual machine and we will access this managed identity within a container that runs on that specific virtual machine. This case can be useful in complex deployment scenarios where you have multiple containers inside a virtual machine and you want to deploy using managed identity on azure.

The first thing you will need is the system assigned managed identity on the virtual machine.

Then you can run your containers inside the virtual machine. In my case the containers are windows based as a result I will use the route print command to show the routing table.

Run the following Commands to expose the managed identity endpoint

$gateway = (Get-NetRoute | Where { $_.DestinationPrefix -eq '0.0.0.0/0' } | Sort-Object RouteMetric | Select NextHop).NextHop
$ifIndex = (Get-NetAdapter -InterfaceDescription "Hyper-V Virtual Ethernet*" | Sort-Object | Select ifIndex).ifIndex
New-NetRoute -DestinationPrefix 169.254.169.254/32 -InterfaceIndex $ifIndex -NextHop $gateway -PolicyStore ActiveStore # metadata API

After the successful add of the route the managed identity endpoint should be redirected in the gateway and from there you will be able to authenticate.

We can verify the procedure by executing a key vault managed identity secret retrieval.

$token = Invoke-WebRequest -Uri 'http://169.254.169.254/metadata/identity/oauth2/token?api-version=2018-02-01&resource=https%3A%2F%2Fvault.azure.net' -Headers @{Metadata="true"} -UseBasicParsing
$tokenvalue = ($token.Content | ConvertFrom-Json).access_token

Retrieve secret:

Invoke-WebRequest -Uri "https://test.vault.azure.net/secrets/testsecret/d9ce520dfdfdf4bdc9a41f5572069708c?api-version=7.3" -Headers @{Authorization = "Bearer $tokenvalue"} -UseBasicParsing

At last you can login using Managed Identity from the container using the powershell module.

References:

Co authored with Giannis Anastasiou @ Vivawallet