Use Change Analysis in Azure Monitor (preview)

Artikel
06/08/2022
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While standard monitoring solutions might alert you to a live site issue, outage, or component failure, they often don't explain the cause. For example, your site worked five minutes ago, and now it's broken. What changed in the last five minutes?

We've designed Change Analysis to answer that question in Azure Monitor.

Building on the power of Azure Resource Graph, Change Analysis:

Provides insights into your Azure application changes.
Increases observability.
Reduces mean time to repair (MTTR).

Important

Change Analysis is currently in preview. This version:

Is provided without a service-level agreement.
Is not recommended for production workloads.
Includes unsupported features and might have constrained capabilities.

For more information, see Supplemental terms of use for Microsoft Azure previews.

Note

Change Analysis is currently only available in Public Azure Cloud.

Overview

Change Analysis detects various types of changes, from the infrastructure layer through application deployment. Change Analysis is a subscription-level Azure resource provider that:

Checks resource changes in the subscription.
Provides data for various diagnostic tools to help users understand what changes might have caused issues.

The following diagram illustrates the architecture of Change Analysis:

Architecture diagram of how Change Analysis gets change data and provides it to client tools

Supported resource types

Azure Monitor Change Analysis service supports resource property level changes in all Azure resource types, including common resources like:

Virtual Machine
Virtual machine scale set
App Service
Azure Kubernetes Service (AKS)
Azure Function
Networking resources:
- Network Security Group
- Virtual Network
- Application Gateway, etc.
Data services:
- Storage
- SQL
- Redis Cache
- Cosmos DB, etc.

Data sources

Azure Monitor's Change Analysis queries for:

Azure Resource Manager tracked properties.
Proxied configurations.
Web app in-guest changes.

Change Analysis also tracks resource dependency changes to diagnose and monitor an application end-to-end.

Azure Resource Manager tracked properties changes

Using Azure Resource Graph, Change Analysis provides a historical record of how the Azure resources that host your application have changed over time. The following tracked settings can be detected:

Managed identities
Platform OS upgrade
Hostnames

Azure Resource Manager proxied setting changes

Unlike Azure Resource Graph, Change Analysis securely queries and computes IP Configuration rules, TLS settings, and extension versions to provide more change details in the app.

Changes in web app deployment and configuration (in-guest changes)

Every 30 minutes, Change Analysis captures the deployment and configuration state of an application. For example, it can detect changes in the application environment variables. The tool computes the differences and presents the changes.

Unlike Azure Resource Manager changes, code deployment change information might not be available immediately in the Change Analysis tool. To view the latest changes in Change Analysis, select Refresh.

Screenshot of the Scan changes now button

If you don't see changes within 30 minutes, refer to our troubleshooting guide.

Currently, all text-based files under site root wwwroot with the following extensions are supported:

*.json
*.xml
*.ini
*.yml
*.config
*.properties
*.html
*.cshtml
*.js
requirements.txt
Gemfile
Gemfile.lock
config.gemspec

Dependency changes

Changes to resource dependencies can also cause issues in a resource. For example, if a web app calls into a Redis cache, the Redis cache SKU could affect the web app performance.

As another example, if port 22 was closed in a virtual machine's Network Security Group, it will cause connectivity errors.

Web App diagnose and solve problems navigator (Preview)

To detect changes in dependencies, Change Analysis checks the web app's DNS record. In this way, it identifies changes in all app components that could cause issues.

Currently the following dependencies are supported in Web App Diagnose and solve problems | Navigator (Preview):

Web Apps
Azure Storage
Azure SQL

Change Analysis detects related resources. Common examples are:

Network Security Group
Virtual Network
Azure Monitor Gateway
Load Balancer related to a Virtual Machine.

Network resources are usually provisioned in the same resource group as the resources using it. Filter the changes by resource group to show all changes for the virtual machine and its related networking resources.

Screenshot of Networking changes

Azure Monitor's Change Analysis service enablement

The Change Analysis service:

Computes and aggregates change data from the data sources mentioned earlier.
Provides a set of analytics for users to:
- Easily navigate through all resource changes.
- Identify relevant changes in the troubleshooting or monitoring context.

Enable Change Analysis

You'll need to register the Microsoft.ChangeAnalysis resource provider with an Azure Resource Manager subscription to make the tracked properties and proxied settings change data available. The Microsoft.ChangeAnalysis resource is automatically registered as you either:

Enter the Web App Diagnose and Solve Problems tool, or
Bring up the Change Analysis standalone tab.

Enable Change Analysis for web app in-guest changes

For web app in-guest changes, separate enablement is required for scanning code files within a web app. For more information, see Change Analysis in the Diagnose and solve problems tool section.

Note

You may not immediately see web app in-guest file changes and configuration changes. Restart your web app and you should be able to view changes within 30 minutes. If not, refer to the troubleshooting guide.

Select Availability and Performance.
Select Application Changes (Preview).

The link leads to Azure Monitor's Change Analysis UI scoped to the web app.
Enable web app in-guest change tracking by either:
- Selecting Enable Now in the banner, or
- Selecting Configure from the top menu.
Toggle on Change Analysis status and select Save.
- The tool displays all web apps under an App Service plan, which you can toggle on and off individually.

You can also view change data via the Web App Down and Application Crashes detectors. The graph summarizes:

The change types over time.
Details on those changes.

By default, the graph displays changes from within the past 24 hours help with immediate problems.

Screenshot of the change diff view

Enable Change Analysis at scale for Web App in-guest file and environment variable changes

If your subscription includes several web apps, enabling the service at the web app level would be inefficient. Instead, run the following script to enable all web apps in your subscription.

Pre-requisites

PowerShell Az Module. Follow instructions at Install the Azure PowerShell module

Run the following script:

# Log in to your Azure subscription
Connect-AzAccount

# Get subscription Id
$SubscriptionId = Read-Host -Prompt 'Input your subscription Id'

# Make Feature Flag visible to the subscription
Set-AzContext -SubscriptionId $SubscriptionId

# Register resource provider
Register-AzResourceProvider -ProviderNamespace "Microsoft.ChangeAnalysis"

# Enable each web app
$webapp_list = Get-AzWebApp | Where-Object {$_.kind -eq 'app'}
foreach ($webapp in $webapp_list)
{
    $tags = $webapp.Tags
    $tags[“hidden-related:diagnostics/changeAnalysisScanEnabled”]=$true
    Set-AzResource -ResourceId $webapp.Id -Tag $tags -Force
}

Next steps

Learn about visualizations in Change Analysis
Learn how to troubleshoot problems in Change Analysis
Enable Application Insights for Azure App Services apps.
Enable Application Insights for Azure VM and Azure virtual machine scale set IIS-hosted apps.