Track a web app outage using Change Analysis

When issues happen, one of the first things to check is what changed in application, configuration and resources to triage and root cause issues. Change Analysis provides a centralized view of the changes in your subscriptions for up to the past 14 days to provide the history of changes for troubleshooting issues.

To track an outage, we will:

• Clone, create, and deploy a sample web application with a storage account.
• Enable Change Analysis to track changes for Azure resources and for Azure Web App configurations
• Troubleshoot a Web App issue using Change Analysis

Pre-requisites

• Install .NET 7.0 or above.
• Install the Azure CLI.

Set up the test application

Clone

1. In your preferred terminal, log in to your Azure subscription.

az login
az account set --s {azure-subscription-id}

1. Clone the sample web application with storage to test Change Analysis.

git clone https://github.com/Azure-Samples/changeanalysis-webapp-storage-sample.git

1. Change the working directory to the project folder.

cd changeanalysis-webapp-storage-sample

Run the PowerShell script

1. Open Publish-WebApp.ps1.

2. Edit the SUBSCRIPTION_ID and LOCATION environment variables.

   Environment variable	Description
   SUBSCRIPTION_ID	Your Azure subscription ID.
   LOCATION	The location of the resource group where you'd like to deploy the sample application.

3. Run the script from the ./changeanalysis-webapp-storage-sample directory.

./Publish-WebApp.ps1

Enable Change Analysis

In the Azure portal, navigate to the Change Analysis standalone UI. Page loading may take a few minutes as the Microsoft.ChangeAnalysis resource provider is registered.

Once the Change Analysis page loads, you can see resource changes in your subscriptions. To view detailed web app in-guest change data:

• Select Enable now from the banner, or
• Select Configure from the top menu.

In the web app in-guest enablement pane, select the web app you'd like to enable:

Now Change Analysis is fully enabled to track both resources and web app in-guest changes.

Simulate a web app outage

In a typical team environment, multiple developers can work on the same application without notifying the other developers. Simulate this scenario and make a change to the web app setting:

az webapp config appsettings set -g {resourcegroup_name} -n {webapp_name} --settings AzureStorageConnection=WRONG_CONNECTION_STRING 

Visit the web app URL to view the following error:

Troubleshoot the outage using Change Analysis

In the Azure portal, navigate to the Change Analysis overview page. Since you've triggered a web app outage, you'll see an entry of change for AzureStorageConnection:

Since the connection string is a secret value, we hide it on the overview page for security purposes. With sufficient permission to read the web app, you can select the change to view details around the old and new values:

The change details pane also shows important information, including who made the change.

Now that you've discovered the web app in-guest change and understand next steps, you can proceed with troubleshooting the issue.

Virtual network changes

Knowing what changed in your application's networking resources is critical due to their effect on connectivity, availability, and performance. Change Analysis supports all network resource changes and captures those changes immediately. Networking changes include:

• Firewalls created or edited
• Network critical changes (for example, blocking port 22 for TCP connections)
• Load balancer changes
• Virtual network changes

The sample application includes a virtual network to make sure the application remains secure. Via the Azure portal, you can view and assess the network changes captured by Change Analysis.

Next steps

Learn more about Change Analysis.