How does sampling work and when should I configure it?

Sampling reduces the volume of telemetry sent to Application Insights while preserving statistically accurate metrics. Adaptive sampling (the default in ASP.NET SDKs) automatically adjusts the rate to stay near a target volume. Fixed-rate sampling applies a consistent percentage across all telemetry. Ingestion sampling is applied server-side on telemetry that has already been sent. For production applications generating more than 5 GB/month, configure sampling to control costs. A 25% sampling rate typically provides sufficient data for trend analysis while reducing costs by 75%.

What is the difference between URL ping tests and standard tests?

URL ping tests send a single HTTP GET request from selected Azure locations and check for a valid response with optional content matching. Standard tests (formerly multi-step) support HEAD, GET, and POST methods with custom headers, request bodies, SSL certificate validation, response time thresholds, and dependent request tracking. Standard tests are more flexible and recommended for new availability monitoring. Both test types run at 5-15 minute intervals from up to 16 Azure locations, and you can alert on consecutive failures from a configured number of locations.

Application Insights Config Builder

MonitoringAzure

Build Application Insights configurations with availability tests and sampling.

Application Insights Configuration

Build Application Insights configs with availability tests, sampling, smart detection, and diagnostics.

Required Fields

nameresourceGroupapplicationTypeworkspaceResourceIdretentionInDays

{
  "name": "appi-webapp-prod",
  "resourceGroup": "rg-monitoring",
  "location": "eastus2",
  "kind": "web",
  "applicationType": "web",
  "workspaceResourceId": "/subscriptions/00000000-0000-0000-0000-000000000000/resourceGroups/rg-monitoring/providers/Microsoft.OperationalInsights/workspaces/law-central-prod",
  "retentionInDays": 90,
  "ingestionMode": "LogAnalytics",
  "publicNetworkAccessForIngestion": "Enabled",
  "publicNetworkAccessForQuery": "Enabled",
  "disableLocalAuth": false,
  "samplingSettings": {
    "isEnabled": true,
    "maxTelemetryItemsPerSecond": 20,
    "excludedTypes": "Exception;Trace"
  },
  "liveMetrics": {
    "enabled": true,
    "authenticationApiKey": false
  },
  "availabilityTests": [
    {
      "name": "Homepage Availability",
      "kind": "standard",
      "url": "https://www.contoso.com",
      "frequency": 300,
      "timeout": 120,
      "enabled": true,
      "locations": [
        { "id": "us-va-ash-azr", "displayName": "East US" },
        { "id": "emea-nl-ams-azr", "displayName": "West Europe" },
        { "id": "apac-sg-sin-azr", "displayName": "Southeast Asia" }
      ],
      "expectedHttpStatusCode": 200,
      "sslCheck": true,
      "sslCertRemainingLifetimeCheck": 7
    },
    {
      "name": "API Health Check",
      "kind": "standard",
      "url": "https://api.contoso.com/health",
      "frequency": 300,
      "timeout": 30,
      "enabled": true,
      "locations": [
        { "id": "us-va-ash-azr", "displayName": "East US" },
        { "id": "emea-gb-db3-azr", "displayName": "UK South" }
      ],
      "expectedHttpStatusCode": 200
    }
  ],
  "smartDetection": {
    "failureAnomalies": true,
    "requestDurationDegradation": true,
    "dependencyDurationDegradation": true,
    "traceSeverityDetector": true,
    "exceptionVolumeChangedDetector": true,
    "memoryLeakDetector": true,
    "potentialSecurityIssueDetector": true
  },
  "diagnosticSettings": {
    "name": "ds-appi-to-law",
    "logs": [
      { "category": "AppAvailabilityResults", "enabled": true },
      { "category": "AppBrowserTimings", "enabled": true },
      { "category": "AppEvents", "enabled": true },
      { "category": "AppExceptions", "enabled": true },
      { "category": "AppMetrics", "enabled": true },
      { "category": "AppRequests", "enabled": true },
      { "category": "AppDependencies", "enabled": true },
      { "category": "AppTraces", "enabled": true }
    ],
    "workspaceId": "/subscriptions/00000000-0000-0000-0000-000000000000/resourceGroups/rg-monitoring/providers/Microsoft.OperationalInsights/workspaces/law-central-prod"
  }
}

Generated Output

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About This Tool

Azure Application Insights is an APM (Application Performance Management) service in Azure Monitor that provides deep observability into application performance, availability, and usage. Configuration involves setting up the instrumentation connection string, configuring sampling to control data volume and cost, defining availability tests (URL ping and multi-step), setting up custom metrics and dimensions, and configuring alerting on performance anomalies. The Config Builder helps you define Application Insights settings including sampling percentages, availability test configurations, and smart detection rules.

When to Use This Tool

•Configuring adaptive sampling that automatically adjusts telemetry volume to stay within budget while preserving representative data
•Setting up multi-location availability tests that probe application endpoints and alert on failures or high latency
•Defining custom dimensions and metrics for tracking business-specific KPIs alongside technical telemetry

Frequently Asked Questions

How does sampling work and when should I configure it?: Sampling reduces the volume of telemetry sent to Application Insights while preserving statistically accurate metrics. Adaptive sampling (the default in ASP.NET SDKs) automatically adjusts the rate to stay near a target volume. Fixed-rate sampling applies a consistent percentage across all telemetry. Ingestion sampling is applied server-side on telemetry that has already been sent. For production applications generating more than 5 GB/month, configure sampling to control costs. A 25% sampling rate typically provides sufficient data for trend analysis while reducing costs by 75%.
What is the difference between URL ping tests and standard tests?: URL ping tests send a single HTTP GET request from selected Azure locations and check for a valid response with optional content matching. Standard tests (formerly multi-step) support HEAD, GET, and POST methods with custom headers, request bodies, SSL certificate validation, response time thresholds, and dependent request tracking. Standard tests are more flexible and recommended for new availability monitoring. Both test types run at 5-15 minute intervals from up to 16 Azure locations, and you can alert on consecutive failures from a configured number of locations.

Related Learning Guides

Azure Monitor & Application Insights26 min read

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