why does app insights need to be turned on manually after automated release?

Question

Why doesn't app insights turn on automatically after the release?

After executing the automated release, I'm getting this when navigating to app insights in the portal:

Here's how I've defined this in my ARM template:

{
  "type": "microsoft.insights/components",
  "kind": "web",
  "name": "[parameters('webAppName')]",
  "apiVersion": "2015-05-01",
  "location": "[parameters('location')]",
  "tags": {
    "[concat('hidden-link:', resourceGroup().id, '/providers/Microsoft.Web/sites/', parameters('webAppName'))]": "Resource",
    "displayName": "[parameters('webAppName')]"
  },
  "properties": {
    "Application_Type": "web"
  },
  "dependsOn": []
}

What am I doing wrong? Why isn't app insights automatically turned on?

Please note that I've added the following appsettings:

Answer 1

The accepted answer is outdated. It's not recommended to use APPINSIGHTS_INSTRUMENTATIONKEY with APPLICATIONINSIGHTS_CONNECTION_STRING. Whichever is provided last wins.

Using instrumentation key is deprecated, we should transition to using APPLICATIONINSIGHTS_CONNECTION_STRING instead.

Otherwise provided answer holds true. More info here:

https://learn.microsoft.com/en-us/azure/azure-monitor/app/migrate-from-instrumentation-keys-to-connection-strings

Answer 2

I had to set up 4 app settings for it to automatically register and turn on app-insights (using bicep in this case):

{
  name: 'APPLICATIONINSIGHTS_CONNECTION_STRING'
  value: applicationInsights.properties.ConnectionString
}
{
  name: 'APPINSIGHTS_INSTRUMENTATIONKEY'
  value: applicationInsights.properties.InstrumentationKey
}
{
  name: 'ApplicationInsightsAgent_EXTENSION_VERSION'
  value: '~3'
}
{
  name: 'XDT_MicrosoftApplicationInsights_Mode'
  value: 'recommended'
}

Answer 3

In order for the Azure Portal to show an active integration with Application Insights, you need to set two app settings. The reason is that you also need to configure the Application Insights Agent Extension.

Note that setting the InstrumentationKey(deprecated) or connection string might be enough for your application to send telemetry to ApplicationInsights, e.g. if you are using ASP.NET Core and the corresponding Nuget package. But you will need both settings for the portal to show the active integration.

{
    "resources": [
        {
            "name": "[parameters('name')]",
            "type": "Microsoft.Web/sites",
            "properties": {
                "siteConfig": {
                    "appSettings": [
                        {
                            "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"
}

See also my other answer on this: Azure Cli How to enable Application Insights for webapp

Edit: updated based on the new information in the answer by BearOakheart.