Troubleshooting .NET automatic instrumentation issues

General steps

If you encounter any issue with OpenTelemetry .NET Automatic Instrumentation, there are steps that can help you understand the problem.

Enable detailed logging

Detailed debug logs can help you troubleshoot instrumentation issues, and can be attached to issues in this project to facilitate investigation.

To get the detailed logs from the OpenTelemetry .NET Automatic Instrumentation, set the OTEL_LOG_LEVEL environment variable to debug before the instrumented process starts.

By default, the library writes the log files under predefined locations. If needed, change the default location by updating the OTEL_DOTNET_AUTO_LOG_DIRECTORY environment variable.

After obtaining the logs, remove the OTEL_LOG_LEVEL environment variable, or set it to less verbose level to avoid unnecessary overhead.

Enable host tracing

Host tracing can be used to gather the information needed to investigate the problems related to various issues, like assemblies not being found. Set the following environment variables:

COREHOST_TRACE=1
COREHOST_TRACEFILE=corehost_verbose_tracing.log

Then restart the application to collect the logs.

Common issues

No telemetry is produced

There is no telemetry generated. There are no logs in OpenTelemetry .NET Automatic Instrumentation internal logs location.

It might occur that the .NET Profiler is unable to attach and therefore no logs would be emitted.

The most common reason is that the instrumented application has no permissions to load the OpenTelemetry .NET Automatic Instrumentation assemblies.

Could not install package ‘OpenTelemetry.AutoInstrumentation.Runtime.Native’

When adding the NuGet packages to your project you get an error message similar to:

Could not install package 'OpenTelemetry.AutoInstrumentation.Runtime.Native 1.0.0-rc.1'. You are trying to install this package into a project that targets '.NETFramework,Version=v4.7.2', but the package does not contain any assembly references or content files that are compatible with that framework. For more information, contact the package author.

The NuGet packages don’t support old-style csproj projects. Either deploy the automatic instrumentation to the machine instead of using NuGet packages, or migrate your project to the SDK style csproj.

Performance issues

If high CPU usage occurs, make sure that you have not enabled the automatic instrumentation globally by setting the environment variables at system or user scope.

If the usage of system or user scope is intentional, use the OTEL_DOTNET_AUTO_EXCLUDE_PROCESSES environment variables to exclude applications from the automatic instrumentation.

dotnet CLI tool is crashing

You get error messages similar to the one below when running an app, for example with dotnet run:

PS C:\Users\Administrator\Desktop\OTelConsole-NET6.0> dotnet run My.Simple.Console
Unhandled exception. System.Reflection.TargetInvocationException: Exception has been thrown by the target of an invocation.
---> System.Reflection.TargetInvocationException: Exception has been thrown by the target of an invocation.
---> System.TypeInitializationException: The type initializer for 'OpenTelemetry.AutoInstrumentation.Loader.Startup' threw an exception.
---> System.Reflection.TargetInvocationException: Exception has been thrown by the target of an invocation.
---> System.IO.FileNotFoundException: Could not load file or assembly 'Microsoft.Extensions.Configuration.Abstractions, Version=7.0.0.0, Culture=neutral, PublicKeyToken=adb9793829ddae60'. The system cannot find the file specified.

With version v0.6.0-beta.1 and lower, there were issues when instrumenting the dotnet CLI tool.

Therefore, if you are using one of these versions, we advise executing dotnet build before instrumenting the terminal session or calling it in a separate terminal session.

See #1744 for more information.

Assembly version conflicts

Error message similar to the one below:

Unhandled exception. System.IO.FileNotFoundException: Could not load file or assembly 'Microsoft.Extensions.DependencyInjection.Abstractions, Version=7.0.0.0, Culture=neutral, PublicKeyToken=adb9793829ddae60'. The system cannot find the file specified.

File name: 'Microsoft.Extensions.DependencyInjection.Abstractions, Version=7.0.0.0, Culture=neutral, PublicKeyToken=adb9793829ddae60'
   at Microsoft.AspNetCore.Builder.WebApplicationBuilder..ctor(WebApplicationOptions options, Action`1 configureDefaults)
   at Microsoft.AspNetCore.Builder.WebApplication.CreateBuilder(String[] args)
   at Program.<Main>$(String[] args) in /Blog.Core/Blog.Core.Api/Program.cs:line 26

OpenTelemetry .NET NuGet packages and its dependencies are deployed with the OpenTelemetry .NET Automatic Instrumentation.

To handle dependency versions conflicts, update the instrumented application’s project references to use the same versions as OpenTelemetry .NET Automatic Instrumentation.

A simple way to ensure that no such conflicts happen is to add the OpenTelemetry.AutoInstrumentation package to your application. For instructions about how to add it to your application, see Using the OpenTelemetry.AutoInstrumentation NuGet packages.

Alternatively add only the conflicting packages to your project. The following dependencies are used by OpenTelemetry .NET Automatic Instrumentation:

• OpenTelemetry.AutoInstrumentation
• OpenTelemetry.AutoInstrumentation.AdditionalDeps

Find their versions in the following locations:

• Directory.Packages.props
• src/Directory.Packages.props
• src/OpenTelemetry.AutoInstrumentation.AdditionalDeps/Directory.Packages.props

By default, assembly references for .NET Framework applications are redirected during runtime to the versions used by the automatic instrumentation. This behavior can be controlled through the OTEL_DOTNET_AUTO_NETFX_REDIRECT_ENABLED setting.

If the application already ships binding redirection for assemblies used by automatic instrumentation this automatic redirection may fail, see #2833. Check if any existing binding redirect prevent redirection to the versions listed at netfx_assembly_redirection.h.

For the automatic redirection above to work there are two specific scenarios that require the assemblies used to instrument .NET Framework applications, the ones under the netfx folder of the installation directory, to be also installed into the Global Assembly Cache (GAC):

1. Monkey patch instrumentation of assemblies loaded as domain-neutral.
2. Assembly redirection for strong-named applications if the app also ships different versions of some assemblies also shipped in the netfx folder.

If you are having problems in one of the scenarios above run again the Install-OpenTelemetryCore command from the PowerShell installation module to ensure that the required GAC installations are updated.

For more information about the GAC usage by the automatic instrumentation, see here.

See #2269 and #2296 for more information.

Assembly in AdditionalDeps was not found

Symptoms

You get an error message similar to the following:

An assembly specified in the application dependencies manifest (OpenTelemetry.AutoInstrumentation.AdditionalDeps.deps.json) was not found

This might be related to the following issues:

• #1744
• #2181

Other issues

If you encounter an issue not listed on this page, see General steps to collect additional diagnostic information. This might help facilitate troubleshooting.