Azure-Admin

Lab 09a - Implement Web Apps

Lab introduction

In this lab, you learn about Azure web apps. You learn to configure a web app to display a Hello World application in an external GitHub repository. You learn to create a staging slot and swap with the production slot. You also learn about autoscaling to accommodate demand changes.

This lab requires an Azure subscription. Your subscription type may affect the availability of features in this lab. You may change the region, but the steps are written using East US.

Estimated timing: 20 minutes

Lab scenario

Your organization is interested in Azure Web apps for hosting your company websites. The websites are currently hosted in an on-premises data center. The websites are running on Windows servers using the PHP runtime stack. The hardware is nearing end-of-life and will soon need to be replaced. Your organization wants to avoid new hardware costs by using Azure to host the websites.

Interactive lab simulations

There are interactive lab simulations that you might find useful for this topic. The simulation lets you to click through a similar scenario at your own pace. There are differences between the interactive simulation and this lab, but many of the core concepts are the same. An Azure subscription is not required.

• Create a web app. Create a web app that runs a Docker container.

• Implement Azure web apps. Create an Azure web app, manage the deployment, and scale the app.

Architecture diagram

Job skills

• Task 1: Create and configure an Azure web app.
• Task 2: Create and configure a deployment slot.
• Task 3: Configure web app deployment settings.
• Task 4: Swap deployment slots.
• Task 5: Configure and test autoscaling of the Azure web app.

Task 1: Create and configure an Azure web app

In this task, you create an Azure web app. Azure App Services is a Platform As a Service (PAAS) solution for web, mobile, and other web-based applications. Azure web apps is part Azure App Services hosting most runtime environments, such as PHP, Java, and .NET. The app service plan that you select determines the web app compute, storage, and features.

1. Sign in to the Azure portal - https://portal.azure.com.

2. Search for and select App services.

3. Select + Create, from drop-down menu, Web App. Notice the other choices.

4. On the Basics tab of the Create Web App blade, specify the following settings (leave others with their default values):

   Setting	Value
   Subscription	your Azure subscription
   Resource group	az104-rg9 (If necessary, select Create new)
   Web app name	any globally unique name
   Publish	Code
   Runtime stack	PHP 8.2
   Operating system	Linux
   Region	East US
   Pricing plans	accept the defaults
   Zone redundancy	accept the defaults

5. Click Review + create, and then Create.

   Note: Wait until the Web App is created before you proceed to the next task. This should take about a minute.

6. After the deployment, select Go to resource.

Task 2: Create and configure a deployment slot

In this task, you will create a staging deployment slot. Deployment slots enable you to perform testing prior to making your app available to the public (or your end users). After you have performed testing, you can swap the slot from development or staging to production. Many organizations use slots to perform pre-production testing. Additionally, many organizations run multiple slots for every application (for example, development, QA, test, and production).

1. On the blade of the newly deployed Web App, click the Default domain link to display the default web page in a new browser tab.

2. Close the new browser tab and, back in the Azure portal, in the Deployment section of the Web App blade, click Deployment slots.

   Note: The Web App, at this point, has a single deployment slot labeled PRODUCTION (May not display until you create the staging slot).

3. Click + Add slot, and add a new slot with the following settings:

   Setting	Value
   Name	staging
   Clone settings from	Do not clone settings

4. Select Add.

5. Back on the Deployment slots blade of the Web App, click the entry representing the newly created staging slot.

   Note: This will open the blade displaying the properties of the staging slot.

6. Review the staging slot blade and note that its URL differs from the one assigned to the production slot.

Task 3: Configure Web App deployment settings

In this task, you will configure Web App deployment settings. Deployment settings allow for continuous deployment. This ensures that the app service has the latest version of the application.

1. In the staging slot, select Deployment Center and then select Settings.

   Note: Make sure you are on the staging slot blade (instead than the production slot).

2. In the Source drop-down list, select External Git. Notice the other choices.

3. In the repository field, enter https://github.com/Azure-Samples/php-docs-hello-world

4. In the branch field, enter master.

5. Select Save.

6. From the staging slot, select Overview.

7. Select the Default domain link, and open the URL in a new tab.

8. Verify that the staging slot displays Hello World.

Note: The deployment may take a minute. Be sure to Refresh the application page.

Task 4: Swap deployment slots

In this task, you will swap the staging slot with the production slot. Swapping a slot allows you to use the code that you have tested in your staging slot, and move it to production. The Azure portal will also prompt you if you need to move other application settings that you have customized for the slot. Swapping slots is a common task for application teams and application support teams, especially those deploying routine app updates and bug fixes.

1. Navigate back to the Deployment slots blade, and then select Swap.

2. Review the default settings and click Swap.

3. On the Overview blade of the Web App select the Default domain link to display the website home page.

4. Verify the production web page displays the Hello World! page.

   Note: Copy the Default domain URL you will need it for load testing in the next task.

Task 5: Configure and test Autoscaling of the Azure web app

In this task, you will configure and test autoscaling of Azure web app.

1. On the blade displaying the production slot of the web app, in the Settings section, click Scale out (App Service plan).

2. In the Scaling section, Scale out method, select Rules Based

3. Select the Configure button.

4. Select the Custom autoscale radio button.

5. In the Default* rule section, for Scale mode, Select Scale based on a metric.

6. On the Rules banner that appears, Select Add a rule.

7. On the Scale rule blade, specify the following settings (leave others with their default values):

   Setting	Value
   Metric source	Current resource
   Metric namespace	Standard metrics
   Metric name	CPU Percentage
   Operator	Greater than
   Metric threshold to trigger scale action	2
   Duration (in minutes)	1
   Time grain statistic	Maximum
   Operation	Increase count by
   Cool down (minutes)	2
   Instance count	1

   Note: Obviously these values do not represent a realistic configuration, since their purpose is to trigger autoscaling as soon as possible, without extended wait period.

8. Click Add and, back on the Default* rule for Instance limits, specify the following settings.

   Setting	Value
   Instance limits Minimum	1
   Instance limits Maximum	3
   Instance limits Default	1

9. Click Save.

10. In the Azure portal, open the Azure Cloud Shell by clicking on the icon in the top right of the Azure Portal.

11. If prompted to select either Bash or PowerShell, select PowerShell.

12. From the Cloud Shell pane, run the following to identify the URL of the Azure web app.

    $rgName = 'az104-rg9'
    
    $webapp = Get-AzWebApp -ResourceGroupName $rgName
    

13. From the Cloud Shell pane, run the following to start and infinite loop that sends the HTTP requests to the web app:

    while ($true) { Invoke-WebRequest -Uri $webapp.DefaultHostName }
    

14. Minimize the Cloud Shell pane (but do not close it). In the Autoscale setting blade, take note of the Instance count.

15. Wait for a minute and then refresh the blade

16. Monitor the utilization and the number of instances for a few minutes.

    Note: You may need to Refresh the page.

17. Once you notice that the number of instances has increased to 2, reopen the Cloud Shell pane and terminate the script by pressing Ctrl+C.

18. Close the Cloud Shell pane.

Cleanup your resources

If you are working with your own subscription take a minute to delete the lab resources. This will ensure resources are freed up and cost is minimized. The easiest way to delete the lab resources is to delete the lab resource group.

• In the Azure portal, select the resource group, select Delete the resource group, Enter resource group name, and then click Delete.
• Using Azure PowerShell, Remove-AzResourceGroup -Name resourceGroupName.
• Using the CLI, az group delete --name resourceGroupName.

Key takeaways

Congratulations on completing the lab. Here are the main takeaways for this lab.

• Azure App Services lets you quickly build, deploy, and scale web apps.
• App Service includes support for many developer environments including ASP.NET, Java, PHP, and Python.
• Deployment slots allow you to create separate environments for deploying and testing your web app.
• You can manually or automatically scale a web app to handle additional demand.
• A wide variety of diagnostics and testing tools are available.

Learn more with self-paced training

• Stage a web app deployment for testing and rollback by using App Service deployment slots. Use deployment slots to streamline deployment and roll back a web app in Azure App Service.
• Scale an App Service web app to efficiently meet demand with App Service scale up and scale out. Respond to periods of increased activity by incrementally increasing the resources available and then, to reduce costs, decreasing these resources when activity drops.