Advice on Setting Up Application Insights for Function Apps

Question

Advice on Setting Up Application Insights for Function Apps

DJ 50

Hi,

We need some advice on how to set up Application Insights for our Function Apps. I noticed that all Application Insights for the Function Apps are connected to the same Log Analytics workspace. Should it be set up this way?

Additionally, each of our Function Apps serves a different purpose. One Function App is triggered when a message is received by our IoT Hub. The Application Insight for the IoT Hub needs to be disabled, as we do not need to store device sensor data from the IoT Hub. This would generate an excessive amount of unnecessary data and impact our budget unnecessarily. How can this be disabled?

Lastly, can we configure Application Insights to send email notifications for any exceptions or errors that occur, providing alerts instead of having to log in to the portal?

Best regards,

Khadeer Ali 5,990 Reputation points Microsoft External Staff Moderator

2025-03-17T12:51:35.24+00:00
@DJ ,

To provide the best advice on setting up Application Insights for your Function Apps, we need to clarify a few details:

Log Analytics Workspace Structure

Currently, all Application Insights instances for your Function Apps are connected to the same Log Analytics workspace. While this setup is valid, we’d like to confirm if it aligns with your operational and compliance needs. Please consider the following:

Billing Quotas: Do you require separate billing for different Function Apps?

Retention Periods: Does each Function App have different log retention requirements?

Regional Compliance: Are there regulations requiring different storage regions?

Environment Separation: Would having separate workspaces for development, testing, and production be beneficial?

If none of these factors apply, we recommend keeping the number of workspaces minimal to simplify management.
DJ 50 Reputation points

2025-03-17T15:18:27.09+00:00

@Khadeer Ali

No, we do not require different billing for different Function Apps.

Yes, the Function App needs to have minimal log retention, ideally close to zero. For example, the app that handles IoT Hub does not necessarily need to log everything—the only exception would be error logs. At the moment, it seems that when a device sends a message, the invocation is also logged, which is unnecessary for our requirements. We would like to eliminate the associated costs.

Other Function Apps are API-based and run on HTTPS, so logging can be enabled for debugging purposes when required. However, the maximum retention period should be 30 days.

No, at this stage, we do not have any regional or environment-specific requirements.

So, I assume we need to keep only one workspace. However, could you explain the purpose of the Log Analytics Workspace structure in relation to Application Insights?

How can we disable or limit the interaction of Application insight for the App which we would like to avoid having logs for, with only exception errors being logged.
Sai Prabhu Naveen Parimi 2,260 Reputation points Microsoft External Staff Moderator

2025-03-18T09:04:30.0133333+00:00

@DJ

The relationship between Log Analytics and App Insights. Log Analytics is the log storage and query resource which can be used by both infrastructure-level and application-level solutions. It is about storage and query of log data.

Application Insights is a layer on top of Log Analytics aimed at application-level telemetry and uses the log data stored in Log Analytics to provide an additional bunch of features that make App Insights an Application Performance Management tool.

Both are highly likely to be part of your architecture and provide great features to help you build better apps and operate well used infrastructure

Reference Doc: Manage data retention in a Log Analytics workspace - Azure Monitor | Microsoft Learn
DJ 50 Reputation points

2025-03-18T13:51:17.2733333+00:00

@Sai Prabhu Naveen Parimi

Thanks, how can i restrict what is sent to Application Insight form my Function App?
Khadeer Ali 5,990 Reputation points Microsoft External Staff Moderator

2025-03-18T14:10:03.6266667+00:00
@DJ ,

To restrict what is sent to Application Insights from your Function App and ensure that only exception logs are captured while avoiding unnecessary telemetry, you can configure the host.json file as follows:

Recommended Sample Configuration (host.json)

{ "logging": { "applicationInsights": { "samplingSettings": { "isEnabled": true, "includeTypes": "Exception", "excludeTypes": "Request, Trace, Dependency, Event" } } } }

https://learn.microsoft.com/en-us/azure/azure-functions/configure-monitoring?tabs=v2

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Khadeer Ali 5,990 Reputation points Microsoft External Staff Moderator

2025-03-17T12:51:35.24+00:00

@DJ ,

To provide the best advice on setting up Application Insights for your Function Apps, we need to clarify a few details:

Log Analytics Workspace Structure

Currently, all Application Insights instances for your Function Apps are connected to the same Log Analytics workspace. While this setup is valid, we’d like to confirm if it aligns with your operational and compliance needs. Please consider the following:

Billing Quotas: Do you require separate billing for different Function Apps?

Retention Periods: Does each Function App have different log retention requirements?

Regional Compliance: Are there regulations requiring different storage regions?

Environment Separation: Would having separate workspaces for development, testing, and production be beneficial?

If none of these factors apply, we recommend keeping the number of workspaces minimal to simplify management.
DJ 50 Reputation points

2025-03-17T15:18:27.09+00:00

@Khadeer Ali

No, we do not require different billing for different Function Apps.

Yes, the Function App needs to have minimal log retention, ideally close to zero. For example, the app that handles IoT Hub does not necessarily need to log everything—the only exception would be error logs. At the moment, it seems that when a device sends a message, the invocation is also logged, which is unnecessary for our requirements. We would like to eliminate the associated costs.

Other Function Apps are API-based and run on HTTPS, so logging can be enabled for debugging purposes when required. However, the maximum retention period should be 30 days.

No, at this stage, we do not have any regional or environment-specific requirements.

So, I assume we need to keep only one workspace. However, could you explain the purpose of the Log Analytics Workspace structure in relation to Application Insights?

How can we disable or limit the interaction of Application insight for the App which we would like to avoid having logs for, with only exception errors being logged.
Sai Prabhu Naveen Parimi 2,260 Reputation points Microsoft External Staff Moderator

2025-03-18T09:04:30.0133333+00:00

@DJ

The relationship between Log Analytics and App Insights. Log Analytics is the log storage and query resource which can be used by both infrastructure-level and application-level solutions. It is about storage and query of log data.

Application Insights is a layer on top of Log Analytics aimed at application-level telemetry and uses the log data stored in Log Analytics to provide an additional bunch of features that make App Insights an Application Performance Management tool.

Both are highly likely to be part of your architecture and provide great features to help you build better apps and operate well used infrastructure

Reference Doc: Manage data retention in a Log Analytics workspace - Azure Monitor | Microsoft Learn
DJ 50 Reputation points

2025-03-18T13:51:17.2733333+00:00

@Sai Prabhu Naveen Parimi

Thanks, how can i restrict what is sent to Application Insight form my Function App?
Khadeer Ali 5,990 Reputation points Microsoft External Staff Moderator

2025-03-18T14:10:03.6266667+00:00

@DJ ,

To restrict what is sent to Application Insights from your Function App and ensure that only exception logs are captured while avoiding unnecessary telemetry, you can configure the host.json file as follows:

Recommended Sample Configuration (host.json)

{ "logging": { "applicationInsights": { "samplingSettings": { "isEnabled": true, "includeTypes": "Exception", "excludeTypes": "Request, Trace, Dependency, Event" } } } }

https://learn.microsoft.com/en-us/azure/azure-functions/configure-monitoring?tabs=v2

Answer 1

Khadeer Ali 5,990 Microsoft External Staff Moderator

@DJ ,

Based on our discussion, I have outlined the optimal setup for Application Insights in your Function Apps while ensuring cost efficiency and capturing only relevant logs.

Log Analytics Workspace Structure

You do not require separate billing, regional compliance, or environment-specific requirements. Since Function Apps have minimal retention needs, a single Log Analytics workspace is sufficient to manage all Application Insights telemetry.

Restricting Logs Sent to Application Insights

To control what gets logged, modify the host.json configuration in your Function App:

json
{
  "logging": {
    "applicationInsights": {
      "samplingSettings": {
        "isEnabled": true,
        "includeTypes": "Exception",
        "excludeTypes": "Request, Trace, Dependency, Event"
      }
    }
  }
}

Khadeer Ali 5,990 Reputation points Microsoft External Staff Moderator

2025-03-20T11:39:42.6766667+00:00

@DJ ,

I wanted to check in and see if you still need assistance or have additional questions, feel free to share more details.

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Advice on Setting Up Application Insights for Function Apps

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