Azure Arc empowers you to extend Azure management and services to any infrastructure. One powerful way to leverage Azure Arc is by automating script execution on Azure Arc-enabled servers. In this guide, we’ll walk through using Bicep templates in conjunction with Azure DevOps Pipelines to achieve this automation seamlessly.

Prerequisites

Before we begin, ensure the following:

param arcMachineName string
param storageAccountName string
param storageContainerName string
param scriptFileName string

resource extension 'Microsoft.HybridCompute/machines/extensions@2022-12-27' = {
  name: '${arcMachineName}/customScriptExtension'
  location: resourceGroup().location
  properties: {
    publisher: 'Microsoft.Compute'
    type: 'CustomScriptExtension'
    typeHandlerVersion: '1.10'
    autoUpgradeMinorVersion: true
    settings: {
      fileUris: [
        'https://${storageAccountName}.blob.core.windows.net/${storageContainerName}/${scriptFileName}'
      ]
      commandToExecute: 'powershell -ExecutionPolicy Unrestricted -File ${scriptFileName}'
    }
  }
}

Step 2: Creating the Build Pipeline

The YAML file below outlines the structure and logic of our Build Pipeline. Essentially, it comprises three stages: code linting, deployment validation, and finally, the deployment of resources utilizing the previously crafted Bicep Template. The included Pipeline parameters enable the provision of distinct deployment values during execution. Notably, the pipeline isn’t set to trigger automatically nor is it scheduled for regular execution.

trigger: none

parameters:
  - name: arcMachineName
    displayName: Azure Arc Machine Name
    type: string
    default: ''
  - name: storageAccountName
    displayName: Storage Account Name
    type: string
    default: ''
  - name: storageContainerName
    displayName: Storage Account Container Name
    type: string
    default: ''
  - name: scriptFileName
    displayName: Script File Name
    type: string
    default: ''
  - name: azureResourceManagerConnection
    displayName: Service Connection Name
    type: string
    default: ''
  - name: subscriptionId
    displayName: Subscription Id
    type: string
    default: ''
  - name: resourceGroupName
    displayName: Resource Group Name
    type: string
    default: ''
  - name: location
    displayName: Deployment Location
    type: string
    default: ''

pool:
  vmImage: ubuntu-latest

stages:
  - stage: Lint
    jobs: 
    - job: Lint
      steps:
        - script: |
            az bicep build --file main.bicep
  - stage: Validate
    jobs:
    - job: Validate
      steps:
        - task: AzureResourceManagerTemplateDeployment@3
          inputs:
            connectedServiceName: ${{ parameters.azureResourceManagerConnection}}
            location: ${{ parameters.location}}
            deploymentMode: Validation
            resourceGroupName: ${{ parameters.resourceGroupName}}
            csmFile: main.bicep
            overrideParameters: -arcMachineName ${{ parameters.arcMachineName}} -storageAccountName ${{ parameters.storageAccountName}} -storageContainerName ${{ parameters.storageContainerName}} -scriptFileName ${{ parameters.scriptFileName}}
  - stage: Deploy
    jobs:
      - job: Deploy
        steps:
        - task: AzureResourceManagerTemplateDeployment@3
          inputs:
            deploymentScope: 'Resource Group'
            azureResourceManagerConnection: ${{ parameters.azureResourceManagerConnection}}
            subscriptionId: ${{ parameters.subscriptionId}}
            action: 'Create Or Update Resource Group'
            resourceGroupName: ${{ parameters.resourceGroupName}}
            location: ${{ parameters.location}}
            templateLocation: 'Linked artifact'
            csmFile: 'main.bicep'
            deploymentMode: 'Incremental'
            overrideParameters: -arcMachineName ${{ parameters.arcMachineName}} -storageAccountName ${{ parameters.storageAccountName}} -storageContainerName ${{ parameters.storageContainerName}} -scriptFileName ${{ parameters.scriptFileName}}

To set up the necessary pipeline, start by accessing Azure DevOps and navigating to Pipelines.

Once in the Pipelines section, click on ‘New Pipeline’ at the top right corner.

Select Azure Repos Git, choose your recently created Git repository, and then opt for the Starter Pipeline. Remove all the existing content in the Starter Pipeline and replace it with the provided snippet.

After pasting the snippet, click the dropdown arrow next to the ‘Save and run’ button and select “Save.”

If you opt for a different Git Repository outside of Azure DevOps, the steps outlined earlier might differ in their execution or interface layout.

Step 3 (Optional): Schedule the Pipeline to run using a schedule on a daily basis

To schedule the Pipeline to run for example on a daily basis, just add the following block underneath trigger:none.

schedules:
- cron: "0 0 * * *"
  displayName: DailyScheduledPipeline
  branches:
    include:
    - '*'
  always: true

Step 4: Running the Pipeline and verifying Script Deployment

Navigate to the recently created build pipeline and select ‘Run Pipeline.’ You’ll be prompted for specific inputs. Once you’ve provided all the required information, click ‘Run’ to initiate the process.

If the Pipeline succeeds, you will be presented with the following

To visually confirm the successful execution of the script, go to the Azure Portal and access the Arc-enabled server extensions blade. Validate that the status of the ‘customScriptExtension’ is indicated as ‘Succeeded’.

Finally, click on ‘customScriptExtension’ and examine the Status message.

That’s it! You’re now ready to automate script execution on Azure Arc-enabled VMs using Bicep and Azure DevOps.

In conclusion, leveraging Bicep and Azure DevOps empowers you to manage and automate Azure Arc resources effectively, streamlining your deployment processes.

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