Added information about Azure Login for CI/CD

Author: ntrogh

articles/load-testing/tutorial-cicd-github-actions.md

@@ -56,11 +56,17 @@ The sample application's source repo includes an Apache JMeter script named *Sam
 
 ## Set up GitHub access permissions for Azure
 
-In this section, you'll configure your GitHub repository to have permissions for accessing the Azure Load Testing resource.
+The GitHub Actions workflow needs to authenticate with Azure to access Azure resources. In the sample application, you use the [Azure Login](https://github.com/Azure/login) action and an Azure Active Directory service principal to authenticate with Azure. For other options to authenticate to Azure, see the [Azure and GitHub integration site](/azure/developer/github).
 
-To access Azure resources, you'll create an Azure Active Directory service principal and use role-based access control to assign the necessary permissions.
+In this section, you'll go through the following steps:
 
-1. Run the following Azure CLI command to create a service principal:
+- Create an Azure Active Directory service principal with the Contributor role.
+- Add the service principal as a GitHub secret to the sample application repository.
+- Assign the Load Test Contributor role to the service principal.
+
+Set up your GitHub repository to have permissions to access your Azure load testing resource:
+
+1. Run the following Azure CLI command to create a service principal and assign the Contributor role:
 
     ```azurecli
     az ad sp create-for-rbac --name "my-load-test-cicd" --role contributor \
@@ -108,6 +114,27 @@ To access Azure resources, you'll create an Azure Active Directory service princ
         --subscription "<subscription-name-or-id>"
     ```
 
+You can now use the `AZURE_CREDENTIALS` secret with the Azure Login action in your CI/CD workflow. The following code snippet describes how this for the sample application:
+
+```yml
+jobs:
+  build-and-deploy:
+    # The type of runner that the job will run on
+    runs-on: ubuntu-latest
+
+    # Steps represent a sequence of tasks that will be executed as part of the job
+    steps:
+      # Checks-out your repository under $GITHUB_WORKSPACE, so your job can access it
+      - name: Checkout GitHub Actions 
+        uses: actions/checkout@v2
+        
+      - name: Login to Azure
+        uses: azure/login@v1
+        continue-on-error: false
+        with:
+          creds: ${{ secrets.AZURE_CREDENTIALS }}
+```
+
 ## Configure the GitHub Actions workflow to run a load test
 
 In this section, you'll set up a GitHub Actions workflow that triggers the load test. The sample application repository contains a workflow file *SampleApp.yaml*. The workflow first deploys the sample web application to Azure App Service, and then invokes the load test. The GitHub action uses an environment variable to pass the URL of the web application to the Apache JMeter script.