Does OpenTelemetry setting of Container Apps Environment actually work?

Question

Does OpenTelemetry setting of Container Apps Environment actually work?

Shigeru Nakagaki 120

Hello

I'm trying Function Optimized Container Apps.

I read this article. I configured settings of Container Apps Environment.

resource "azapi_update_resource" "container_apps_environment" {
  type      = "Microsoft.App/managedEnvironments@2025-02-02-preview"
  name      = azurerm_container_app_environment.main.name
  parent_id = data.azurerm_resource_group.main.id
  body = {
    properties = {
      appInsightsConfiguration = {
        connectionString = data.azurerm_application_insights.main.connection_string
      }
      openTelemetryConfiguration = {
        tracesConfiguration = {
          destinations = ["appInsights"]
        }
        logsConfiguration = {
          destinations = ["appInsights"]
        }
      }
    }
  }
}

    "properties": {
        "provisioningState": "Succeeded",
        "daprAIInstrumentationKey": null,
        "daprAIConnectionString": null,
        "vnetConfiguration": {
            "internal": false,
            "infrastructureSubnetId": "/subscriptions/xxx",
            "dockerBridgeCidr": null,
            "platformReservedCidr": "10.1.0.0/16",
            "platformReservedDnsIP": "10.1.0.2"
        },
        "defaultDomain": "xxx.japaneast.azurecontainerapps.io",
        "staticIp": "xxx",
        "appLogsConfiguration": {
            "destination": "azure-monitor",
            "logAnalyticsConfiguration": null
        },
        "openTelemetryConfiguration": {
            "destinationsConfiguration": null,
            "tracesConfiguration": {
                "includeDapr": false,
                "destinations": [
                    "appInsights"
                ]
            },
            "logsConfiguration": {
                "destinations": [
                    "appInsights"
                ]
            },
            "metricsConfiguration": null
        },
        "zoneRedundant": false,
        "availabilityZones": null,
        "kedaConfiguration": {
            "version": "2.16.1"
        },
        "daprConfiguration": {
            "version": "1.13.6-msft.4"
        },
        "ingressConfiguration": null,
        "eventStreamEndpoint": "https://japaneast.azurecontainerapps.dev/subscriptions/xxx/eventstream",
        "customDomainConfiguration": {
            "customDomainVerificationId": "xxx",
            "dnsSuffix": null,
            "certificateKeyVaultProperties": null,
            "certificateValue": null,
            "certificatePassword": null,
            "thumbprint": null,
            "subjectName": null,
            "expirationDate": null
        },
        "workloadProfiles": null,
        "appInsightsConfiguration": {
            "connectionString": null
        },
        "infrastructureResourceGroup": null,
        "peerAuthentication": {
            "mtls": {
                "enabled": false
            }
        },
        "peerTrafficConfiguration": {
            "encryption": {
                "enabled": false
            }
        },
        "publicNetworkAccess": "Enabled",
        "diskEncryptionConfiguration": null
    },
    "identity": {
        "type": "UserAssigned",
        "userAssignedIdentities": {
            "/subscriptions/xxx": {
                "principalId": "xxx",
                "clientId": "xxx"
            }
        }
    }

I believe the reason the connectionString in appInsightsConfiguration is null is because it's a sensitive value.

When I delete APPLICATIONINSIGHTS_CONNECTION_STRING from environment variable of Container Apps (not Container Apps Environment), there is no traces in transaction search of Application Insights.thanks

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Answer 1

Sai Prabhu Naveen Parimi 3,235 Microsoft External Staff Moderator

Hello @Shigeru Nakagaki

The OpenTelemetry settings in Azure Container Apps will function as expected when configured properly. The null value for the connectionString in appInsightsConfiguration confirms that it is a sensitive value, intentionally hidden for security purposes.

If the APPLICATIONINSIGHTS_CONNECTION_STRING environment variable is removed from your Container Apps, traces will not appear in Application Insights. This connection string is critical for the Application Insights SDK to transmit telemetry data. Make sure the connection string is accurately set in your environment variables to ensure successful telemetry data transmission.

Also, verify that your OpenTelemetry agent is configured to send data to the correct destinations as outlined in your settings.

References:

Shigeru Nakagaki 120 Reputation points

2025-08-06T01:12:04.8433333+00:00

Hi, Sai

Function Optimized Container Apps can send telemetry by itself.

What is OpenTelemetry settings of Container Apps Environment for??
Sai Prabhu Naveen Parimi 3,235 Reputation points Microsoft External Staff Moderator

2025-08-06T05:46:01.9233333+00:00
Hello @Shigeru Nakagaki

You’re correct—Function Optimized Container Apps are capable of sending telemetry independently, provided your application is instrumented with the OpenTelemetry SDK and the necessary environment variables, such as APPLICATIONINSIGHTS_CONNECTION_STRING, are configured.

The OpenTelemetry configuration at the Container Apps Environment level is optional. This feature is primarily beneficial if you want to delegate telemetry routing to a managed agent. By doing so, you can direct logs and traces to various destinations like Application Insights, Datadog, or any backend compatible with OTLP, without the need to run a custom collector inside your container.

However, you might consider using the OpenTelemetry agent in cases where:

You need centralized management of telemetry destinations.

You plan to send data to multiple observability platforms.

You would rather not handle telemetry configuration within each individual app.

In summary, the environment-level OpenTelemetry configuration is optional, but it can be quite helpful depending on your requirements.

I hope this explanation provides additional clarity.
Shigeru Nakagaki 120 Reputation points

2025-08-06T09:15:14.78+00:00
I understood.

The document said

If you want to protect your Application Insights resource from misuse, see Microsoft Entra authentication for Application Insights. However, the Application Insights resource must allow local authentication to receive data from the OpenTelemetry data agent.

Current OpenTelemetry agent does not support Entra authentication yet.

When it supports Entra authentication, I'll consider the agent.

Thank you Sai for helping me understand.
Sai Prabhu Naveen Parimi 3,235 Reputation points Microsoft External Staff Moderator

2025-08-06T09:55:50.13+00:00

You're most welcome, Shigeru Nakagaki really glad I could help clear things up! And yes, you caught an important point in the documentation. Thanks again for the thoughtful questions and the engaging conversation.

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Does OpenTelemetry setting of Container Apps Environment actually work?

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