Application Monitoring for Azure App Service and Node.js

Članak
06/07/2022
6 min. za čitanje

Monitoring of your Node.js web applications running on Azure App Services does not require any modifications to the code. This article will walk you through enabling Azure Monitor Application Insights monitoring as well as provide preliminary guidance for automating the process for large-scale deployments.

Enable Application Insights

The easiest way to enable application monitoring for Node.js applications running on Azure App Services is through Azure portal. Turning on application monitoring in Azure portal will automatically instrument your application with Application Insights, and doesn't require any code changes.

Note

If both auto-instrumentation monitoring and manual SDK-based instrumentation are detected, only the manual instrumentation settings will be honored. This is to prevent duplicate data from being sent. To learn more about this, check out the troubleshooting section below.

Auto-instrumentation through Azure portal

You can turn on monitoring for your Node.js apps running in Azure App Service just with one click, no code change required. Application Insights for Node.js is integrated with Azure App Service on Linux - both code-based and custom containers, and with App Service on Windows for code-based apps. The integration is in public preview. The integration adds Node.js SDK, which is in GA.

Select Application Insights in the Azure control panel for your app service, then select Enable.
Choose to create a new resource, or select an existing Application Insights resource for this application.

Note

When you select OK to create the new resource you will be prompted to Apply monitoring settings. Selecting Continue will link your new Application Insights resource to your app service, doing so will also trigger a restart of your app service.
Once you have specified which resource to use, you are all set to go.

Enable client-side monitoring

To enable client-side monitoring for your Node.js application, you need to manually add the client-side JavaScript SDK to your application.

Automate monitoring

In order to enable telemetry collection with Application Insights, only the following Application settings need to be set:

Screenshot of App Service Application Settings with available Application Insights settings.

Application settings definitions

App setting name	Definition	Value
ApplicationInsightsAgent_EXTENSION_VERSION	Main extension, which controls runtime monitoring.	`~2` in Windows or `~3` in Linux.
XDT_MicrosoftApplicationInsights_NodeJS	Flag to control if Node.js agent is included.	0 or 1 (only applicable in Windows).

Note

Profiler and snapshot debugger are not available for Node.js applications

App Service Application settings with Azure Resource Manager

Application settings for App Services can be managed and configured with Azure Resource Manager templates. This method can be used when deploying new App Service resources with Azure Resource Manager automation, or for modifying the settings of existing resources.

The basic structure of the application settings JSON for an app service is below:

      "resources": [
        {
          "name": "appsettings",
          "type": "config",
          "apiVersion": "2015-08-01",
          "dependsOn": [
            "[resourceId('Microsoft.Web/sites', variables('webSiteName'))]"
          ],
          "tags": {
            "displayName": "Application Insights Settings"
          },
          "properties": {
            "key1": "value1",
            "key2": "value2"
          }
        }
      ]

For an example of an Azure Resource Manager template with Application settings configured for Application Insights, this template can be helpful, specifically the section starting on line 238.

Automate the creation of an Application Insights resource and link to your newly created App Service.

To create an Azure Resource Manager template with all the default Application Insights settings configured, begin the process as if you were going to create a new Web App with Application Insights enabled.

Create a new App Service resource with your desired web app information. Enabled Application Insights on the Monitoring tab.
Select Review +create then Download a template for automation at the bottom.

This option generates the latest Azure Resource Manager template with all required settings configured.

Below is a sample, replace all instances of AppMonitoredSite with your site name:

{
    "resources": [
        {
            "name": "[parameters('name')]",
            "type": "Microsoft.Web/sites",
            "properties": {
                "siteConfig": {
                    "appSettings": [
                        {
                            "name": "APPINSIGHTS_INSTRUMENTATIONKEY",
                            "value": "[reference('microsoft.insights/components/AppMonitoredSite', '2015-05-01').InstrumentationKey]"
                        },
                        {
                            "name": "APPLICATIONINSIGHTS_CONNECTION_STRING",
                            "value": "[reference('microsoft.insights/components/AppMonitoredSite', '2015-05-01').ConnectionString]"
                        },
                        {
                            "name": "ApplicationInsightsAgent_EXTENSION_VERSION",
                            "value": "~2"
                        }
                    ]
                },
                "name": "[parameters('name')]",
                "serverFarmId": "[concat('/subscriptions/', parameters('subscriptionId'),'/resourcegroups/', parameters('serverFarmResourceGroup'), '/providers/Microsoft.Web/serverfarms/', parameters('hostingPlanName'))]",
                "hostingEnvironment": "[parameters('hostingEnvironment')]"
            },
            "dependsOn": [
                "[concat('Microsoft.Web/serverfarms/', parameters('hostingPlanName'))]",
                "microsoft.insights/components/AppMonitoredSite"
            ],
            "apiVersion": "2016-03-01",
            "location": "[parameters('location')]"
        },
        {
            "apiVersion": "2016-09-01",
            "name": "[parameters('hostingPlanName')]",
            "type": "Microsoft.Web/serverfarms",
            "location": "[parameters('location')]",
            "properties": {
                "name": "[parameters('hostingPlanName')]",
                "workerSizeId": "[parameters('workerSize')]",
                "numberOfWorkers": "1",
                "hostingEnvironment": "[parameters('hostingEnvironment')]"
            },
            "sku": {
                "Tier": "[parameters('sku')]",
                "Name": "[parameters('skuCode')]"
            }
        },
        {
            "apiVersion": "2015-05-01",
            "name": "AppMonitoredSite",
            "type": "microsoft.insights/components",
            "location": "West US 2",
            "properties": {
                "ApplicationId": "[parameters('name')]",
                "Request_Source": "IbizaWebAppExtensionCreate"
            }
        }
    ],
    "parameters": {
        "name": {
            "type": "string"
        },
        "hostingPlanName": {
            "type": "string"
        },
        "hostingEnvironment": {
            "type": "string"
        },
        "location": {
            "type": "string"
        },
        "sku": {
            "type": "string"
        },
        "skuCode": {
            "type": "string"
        },
        "workerSize": {
            "type": "string"
        },
        "serverFarmResourceGroup": {
            "type": "string"
        },
        "subscriptionId": {
            "type": "string"
        }
    },
    "$schema": "https://schema.management.azure.com/schemas/2014-04-01-preview/deploymentTemplate.json#",
    "contentVersion": "1.0.0.0"
}

Enable through PowerShell

In order to enable the application monitoring through PowerShell, only the underlying application settings need to be changed. Below is a sample, which enables application monitoring for a website called "AppMonitoredSite" in the resource group "AppMonitoredRG", and configures data to be sent to the "012345678-abcd-ef01-2345-6789abcd" instrumentation key.

Note

This article uses the Azure Az PowerShell module, which is the recommended PowerShell module for interacting with Azure. To get started with the Az PowerShell module, see Install Azure PowerShell. To learn how to migrate to the Az PowerShell module, see Migrate Azure PowerShell from AzureRM to Az.

$app = Get-AzWebApp -ResourceGroupName "AppMonitoredRG" -Name "AppMonitoredSite" -ErrorAction Stop
$newAppSettings = @{} # case-insensitive hash map
$app.SiteConfig.AppSettings | %{$newAppSettings[$_.Name] = $_.Value} # preserve non Application Insights application settings.
$newAppSettings["APPINSIGHTS_INSTRUMENTATIONKEY"] = "012345678-abcd-ef01-2345-6789abcd"; # set the Application Insights instrumentation key
$newAppSettings["APPLICATIONINSIGHTS_CONNECTION_STRING"] = "InstrumentationKey=012345678-abcd-ef01-2345-6789abcd"; # set the Application Insights connection string
$newAppSettings["ApplicationInsightsAgent_EXTENSION_VERSION"] = "~2"; # enable the ApplicationInsightsAgent
$app = Set-AzWebApp -AppSettings $newAppSettings -ResourceGroupName $app.ResourceGroup -Name $app.Name -ErrorAction Stop

Troubleshooting

Below is our step-by-step troubleshooting guide for extension/agent based monitoring for Node.js based applications running on Azure App Services.

Windows
Linux

Check that ApplicationInsightsAgent_EXTENSION_VERSION app setting is set to a value of "~2".
Browse to https://yoursitename.scm.azurewebsites.net/ApplicationInsights.
- Confirm that the Application Insights Extension Status is Pre-Installed Site Extension, version 2.8.x.xxxx, is running.
  
  If it is not running, follow the enable Application Insights monitoring instructions.
- Navigate to D:\local\Temp\status.json and open status.json.
Confirm that SDKPresent is set to false, AgentInitializedSuccessfully to true and IKey to have a valid iKey.

Below is an example of the JSON file:
```
    "AppType":"node.js",

    "MachineName":"c89d3a6d0357",

    "PID":"47",

    "AgentInitializedSuccessfully":true,

    "SDKPresent":false,

    "IKey":"00000000-0000-0000-0000-000000000000",

    "SdkVersion":"1.8.10"
```
If SDKPresent is true this indicates that the extension detected that some aspect of the SDK is already present in the Application, and will back-off.

Check that ApplicationInsightsAgent_EXTENSION_VERSION app setting is set to a value of "~3".
Navigate to /var/log/applicationinsights/ and open status.json.

Confirm that SDKPresent is set to false, AgentInitializedSuccessfully to true and IKey to have a valid iKey.

Below is an example of the JSON file:
```
    "AppType":"node.js",

    "MachineName":"c89d3a6d0357",

    "PID":"47",

    "AgentInitializedSuccessfully":true,

    "SDKPresent":false,

    "IKey":"00000000-0000-0000-0000-000000000000",

    "SdkVersion":"1.8.10"
```
If SDKPresent is true this indicates that the extension detected that some aspect of the SDK is already present in the Application, and will back-off.

Connection string and instrumentation key

When codeless monitoring is being used, only the connection string is required. However, we still recommend setting the instrumentation key to preserve backwards compatibility with older versions of the SDK when manual instrumentation is being performed.

Difference between Standard Metrics from Application Insights vs Azure App Service metrics?

Application Insights collects telemetry for those requests which made it to the application. If the failure occurred in WebApps/WebServer, and the request did not reach the user application, then Application Insights will not have any telemetry about it.

The duration for serverresponsetime calculated by Application Insights is not necessarily matching the server response time observed by Web Apps. This is because Application Insights only counts the duration when the request actual reaches user application. If the request is stuck/queued in WebServer, that waiting time will be included in the Web App metrics, but not in Application Insights metrics.

Release notes

For the latest updates and bug fixes, consult the release notes.

Next steps

Monitor Azure Functions with Application Insights.
Enable Azure diagnostics to be sent to Application Insights.
Monitor service health metrics to make sure your service is available and responsive.
Receive alert notifications whenever operational events happen or metrics cross a threshold.
Use Application Insights for JavaScript apps and web pages to get client telemetry from the browsers that visit a web page.
Set up Availability web tests to be alerted if your site is down.

Application Monitoring for Azure App Service and Node.js

Enable Application Insights

Auto-instrumentation through Azure portal

Enable client-side monitoring

Automate monitoring

Application settings definitions

App Service Application settings with Azure Resource Manager

Automate the creation of an Application Insights resource and link to your newly created App Service.

Enable through PowerShell

Troubleshooting

Connection string and instrumentation key

Difference between Standard Metrics from Application Insights vs Azure App Service metrics?

Release notes

Next steps

Povratne informacije