Tracing .NET Core Applications

Compatibility requirements

Supported .NET Core runtimes

The .NET Tracer supports instrumentation on .NET Core 2.1, 3.1, and .NET 5.

For a full list of supported libraries and processor architectures, see Compatibility Requirements.

Installation and getting started

Automatic instrumentation

Notes:

Datadog automatic instrumentation relies on the .NET CLR Profiling API. This API allows only one subscriber (for example, APM). To ensure maximum visibility, run only one APM solution in your application environment.
If you are using both automatic and custom instrumentation, it is important to keep the package versions (for example, MSI and NuGet) in sync.

Installing the tracer

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Download the .NET Tracer MSI installer. Select the MSI installer for the architecture that matches the operating system (x64 or x86).
Run the .NET Tracer MSI installer with administrator privileges.
Enable instrumentation in your service by setting the required environment variables. See the section Instrumenting your service, below.
Create application load.
Visit APM Live Traces.

Download and install the .NET Tracer into the application environment:

Debian or Ubuntu - Download and install the Debian package:

curl -LO https://github.com/DataDog/dd-trace-dotnet/releases/download/v<TRACER_VERSION>/datadog-dotnet-apm_<TRACER_VERSION>_amd64.deb
sudo dpkg -i ./datadog-dotnet-apm_<TRACER_VERSION>_amd64.deb

CentOS or Fedora - Download and install the RPM package:

curl -LO https://github.com/DataDog/dd-trace-dotnet/releases/download/v<TRACER_VERSION>/datadog-dotnet-apm-<TRACER_VERSION>-1.x86_64.rpm
sudo rpm -Uvh datadog-dotnet-apm-<TRACER_VERSION>-1.x86_64.rpm

Alpine or other musl-based distributions - Download the tar archive with the musl-linked binary:

sudo mkdir -p /opt/datadog
curl -L https://github.com/DataDog/dd-trace-dotnet/releases/download/v<TRACER_VERSION>/datadog-dotnet-apm-<TRACER_VERSION>-musl.tar.gz \
| sudo tar xzf - -C /opt/datadog

Other distributions - Download the tar archive with the glibc-linked binary:

sudo mkdir -p /opt/datadog
curl -L https://github.com/DataDog/dd-trace-dotnet/releases/download/v<TRACER_VERSION>/datadog-dotnet-apm-<TRACER_VERSION>.tar.gz \
| sudo tar xzf - -C /opt/datadog

Run the /opt/datadog/createLogPath.sh script, which creates a directory for the log files and sets appropriate directory permissions. The default directory for log files is /var/log/datadog/dotnet.
Enable instrumentation in your service by setting the required environment variables. See the section Instrumenting your service, below.
Create application load.
Visit APM Live Traces.

Instrumenting your service

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Internet Information Services (IIS)

To automatically instrument applications hosted in IIS, completely stop IIS and then start it by running the following commands as an administrator:

Note: You must use a stop and start command. A reset or restart command will not always work.

net stop /y was
net start w3svc

Windows services

To automatically instrument a Windows service, set the CORECLR_ENABLE_PROFILING and CORECLR_PROFILER environment variables for the service in the Windows Registry.

Using the Registry Editor:

In the Registry Editor, create a multi-string value called Environment in the HKLM\System\CurrentControlSet\Services\<SERVICE NAME> key and set the value data to:

CORECLR_ENABLE_PROFILING=1
CORECLR_PROFILER={846F5F1C-F9AE-4B07-969E-05C26BC060D8}

Using the Registry Editor to create environment variables for a Windows service

Using PowerShell:

[string[]] $v = @("CORECLR_ENABLE_PROFILING=1", "CORECLR_PROFILER={846F5F1C-F9AE-4B07-969E-05C26BC060D8}")
Set-ItemProperty HKLM:SYSTEM\CurrentControlSet\Services\<SERVICE NAME> -Name Environment -Value $v

Console applications

To automatically instrument a console application, set the CORECLR_ENABLE_PROFILING and CORECLR_PROFILER environment variables from a batch file before starting your application:

rem Set environment variables
SET CORECLR_ENABLE_PROFILING=1
SET CORECLR_PROFILER={846F5F1C-F9AE-4B07-969E-05C26BC060D8}

rem Start application
dotnet.exe example.dll

Other applications

To enable automatic instrumentation, you must set two environment variables before starting your application:

Name	Value
`CORECLR_ENABLE_PROFILING`	`1`
`CORECLR_PROFILER`	`{846F5F1C-F9AE-4B07-969E-05C26BC060D8}`

Note: The .NET runtime tries to load a profiler into any .NET process started with these environment variables set. You should limit instrumentation only to the applications that need to be instrumented. Don't set these environment variables globally because this causes all .NET processes on the host to load the profiler.

The following environment variables are required to enable automatic instrumentation:

Note: If the .NET Tracer is installed into a path other than the default /opt/datadog path, ensure the paths are changed to match.

Name	Value
`CORECLR_ENABLE_PROFILING`	`1`
`CORECLR_PROFILER`	`{846F5F1C-F9AE-4B07-969E-05C26BC060D8}`
`CORECLR_PROFILER_PATH`	`/opt/datadog/Datadog.Trace.ClrProfiler.Native.so`
`DD_INTEGRATIONS`	`/opt/datadog/integrations.json`
`DD_DOTNET_TRACER_HOME`	`/opt/datadog`

Bash script

To set the required environment variables from a bash file before starting your application:

# Set environment variables
export CORECLR_ENABLE_PROFILING=1
export CORECLR_PROFILER={846F5F1C-F9AE-4B07-969E-05C26BC060D8}
export CORECLR_PROFILER_PATH=/opt/datadog/Datadog.Trace.ClrProfiler.Native.so
export DD_INTEGRATIONS=/opt/datadog/integrations.json
export DD_DOTNET_TRACER_HOME=/opt/datadog

# Start your application
dotnet example.dll

Linux Docker container

To set the required environment variables on a Linux Docker container:

# Set environment variables
ENV CORECLR_ENABLE_PROFILING=1
ENV CORECLR_PROFILER={846F5F1C-F9AE-4B07-969E-05C26BC060D8}
ENV CORECLR_PROFILER_PATH=/opt/datadog/Datadog.Trace.ClrProfiler.Native.so
ENV DD_INTEGRATIONS=/opt/datadog/integrations.json
ENV DD_DOTNET_TRACER_HOME=/opt/datadog

# Start your application
CMD ["dotnet", "example.dll"]

`systemctl` (per service)

When using systemctl to run .NET applications as a service, you can add the required environment variables to be loaded for a specific service.

Create a file called environment.env containing:

CORECLR_ENABLE_PROFILING=1
CORECLR_PROFILER={846F5F1C-F9AE-4B07-969E-05C26BC060D8}
CORECLR_PROFILER_PATH=/opt/datadog/Datadog.Trace.ClrProfiler.Native.so
DD_INTEGRATIONS=/opt/datadog/integrations.json
DD_DOTNET_TRACER_HOME=/opt/datadog
# any other environment variable used by the application

In the service’s configuration file, reference this as an EnvironmentFile in the service block:

[Service]
EnvironmentFile=/path/to/environment.env
ExecStart=<command used to start the application>

Restart the .NET service for the environment variable settings to take effect.

`systemctl` (all services)

Note: The .NET runtime tries to load a profiler into any .NET process that is started with these environment variables set. You should limit instrumentation to only the applications that need to be traced. Don't set these environment variables globally as this causes all .NET processes on the host to load the profiler.

When using systemctl to run .NET applications as a service, you can also set environment variables to be loaded for all services run by systemctl.

Set the required environment variables by running systemctl set-environment:

systemctl set-environment CORECLR_ENABLE_PROFILING=1
systemctl set-environment CORECLR_PROFILER={846F5F1C-F9AE-4B07-969E-05C26BC060D8}
systemctl set-environment CORECLR_PROFILER_PATH=/opt/datadog/Datadog.Trace.ClrProfiler.Native.so
systemctl set-environment DD_INTEGRATIONS=/opt/datadog/integrations.json
systemctl set-environment DD_DOTNET_TRACER_HOME=/opt/datadog

Verify that the environment variables were set by running systemctl show-environment.
Restart the .NET service for the environment variables to take effect.

Configure the Datadog Agent for APM

Install and configure the Datadog Agent to receive traces from your instrumented application. By default the Datadog Agent is enabled in your datadog.yaml file under apm_config with enabled: true and listens for trace traffic at localhost:8126. For containerized environments, follow the links below to enable trace collection in the Datadog Agent.

Dropdown

Set apm_non_local_traffic: true in the apm_config section of your main datadog.yaml configuration file.
See the specific setup instructions to ensure that the Agent is configured to receive traces in a containerized environment:

After instrumenting your application, the tracing client sends traces to localhost:8126 by default. If this is not the correct host and port change it by setting the below env variables:
DD_AGENT_HOST and DD_TRACE_AGENT_PORT.
See Configuration for more information on how to set these variables.

To set up Datadog APM in AWS Lambda, see the Tracing Serverless Functions documentation.

To set up Datadog APM in Azure App Service, see the Tracing Azure App Service Extension documentation.

Tracing is available for a number of other environments, such as Heroku, Cloud Foundry, and AWS Elastic Beanstalk.

For other environments, please refer to the Integrations documentation for that environment and contact support if you are encountering any setup issues.

Custom instrumentation

Note: If you are using both automatic and custom instrumentation, it is important to keep the package versions (for example, MSI and NuGet) in sync.

To use custom instrumentation in your .NET application:

Add the Datadog.Trace NuGet package to your application.
In your application code, access the global tracer through the Datadog.Trace.Tracer.Instance property to create new spans.

For additional details on custom instrumentation and custom tagging, see the .NET Custom Instrumentation documentation.

Configuration

The .NET Tracer has configuration settings which you can set by any of these methods:

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To configure the tracer using environment variables, set the variables before launching the instrumented application.

Windows

rem Set environment variables
SET DD_TRACE_AGENT_URL=http://localhost:8126
SET DD_ENV=prod
SET DD_SERVICE=MyService
SET DD_VERSION=abc123

rem Launch application
example.exe

Note: To set environment variables for a Windows Service, use the multi-string key HKLM\System\CurrentControlSet\Services\{service name}\Environment in the Windows Registry, as described above.

Because IIS runs all applications under one Windows Service, Datadog recommends you use another configuration option (Code, web.config, or JSON file) for application-specific settings such as DD_SERVICE.

Linux

# Set environment variables
export DD_TRACE_AGENT_URL=http://localhost:8126
export DD_ENV=prod
export DD_SERVICE=MyService
export DD_VERSION=abc123

# Launch application
dotnet example.dll

To configure the Tracer in application code, create a TracerSettings instance from the default configuration sources. Set properties on this TracerSettings instance before passing it to a Tracer constructor. For example:

Note: Settings must be set on TracerSettings before creating the Tracer. Changes made to TracerSettings properties after the Tracer is created are ignored.

using Datadog.Trace;
using Datadog.Trace.Configuration;

// read default configuration sources (env vars, web.config, datadog.json)
var settings = TracerSettings.FromDefaultSources();

// change some settings
settings.Environment = "prod";
settings.ServiceName = "MyService";
settings.ServiceVersion = "abc123";
settings.AgentUri = new Uri("http://localhost:8126/");

// create a new Tracer using these settings
var tracer = new Tracer(settings);

// set the global tracer
Tracer.Instance = tracer;

To configure the Tracer using a JSON file, create datadog.json in the instrumented application’s directory. The root JSON object must be an object with a key-value pair for each setting. For example:

{
  "DD_TRACE_AGENT_URL": "http://localhost:8126",
  "DD_ENV": "prod",
  "DD_SERVICE": "MyService",
  "DD_VERSION": "abc123",
}

Configuration settings

Note: On Linux, the names of environment variables are case-sensitive.

Using the methods described above, customize your tracing configuration with the following variables. Use the environment variable name (for example, DD_TRACE_AGENT_URL) when setting environment variables or configuration files. Use the TracerSettings property (for example, AgentUri) when changing settings in code.

Unified Service Tagging

To use Unified Service Tagging, configure the following settings for your services:

DD_ENV: TracerSettings property: Environment
If specified, adds the env tag with the specified value to all generated spans. Added in version 1.17.0.
DD_SERVICE: TracerSettings property: ServiceName
If specified, sets the service name. Otherwise, the .NET Tracer tries to determine service name automatically from application name (IIS application name, process entry assembly, or process name). Added in version 1.17.0.
DD_VERSION: TracerSettings property: ServiceVersion
If specified, sets the version of the service. Added in version 1.17.0.

Optional configuration

The following configuration variables are available for both automatic and custom instrumentation:

DD_TRACE_AGENT_URL: TracerSettings property: AgentUri
Sets the URL endpoint where traces are sent. Overrides DD_AGENT_HOST and DD_TRACE_AGENT_PORT if set.
Default: http://<DD_AGENT_HOST>:<DD_TRACE_AGENT_PORT>
DD_AGENT_HOST: Sets the host where traces are sent (the host running the Agent). Can be a hostname or an IP address. Ignored if DD_TRACE_AGENT_URL is set.
Default: localhost
DD_TRACE_AGENT_PORT: Sets the port where traces are sent (the port where the Agent is listening for connections). Ignored if DD_TRACE_AGENT_URL is set.
Default: 8126
DD_LOGS_INJECTION: TracerSettings property: LogsInjectionEnabled
Enables or disables automatic injection of correlation identifiers into application logs.
DD_MAX_TRACES_PER_SECOND: TracerSettings property: MaxTracesSubmittedPerSecond
The number of traces allowed to be submitted per second.
DD_TRACE_GLOBAL_TAGS: TracerSettings property: GlobalTags
If specified, adds all of the specified tags to all generated spans.
DD_TRACE_DEBUG: TracerSettings property: DebugEnabled
Enables or disables debug logging. Valid values are: true or false.
Default: false
DD_TRACE_HEADER_TAGS: TracerSettings property:HeaderTags
Accepts a map of case-insensitive header keys to tag names and automatically applies matching header values as tags on root spans. Also accepts entries without a specified tag name.
Example: CASE-insensitive-Header:my-tag-name,User-ID:userId,My-Header-And-Tag-Name
Added in version 1.18.3. Response header support and entries without tag names added in version 1.26.0.
DD_TAGS: TracerSettings property: GlobalTags
If specified, adds all of the specified tags to all generated spans.
Example: layer:api,team:intake
Added in version 1.17.0.
DD_TRACE_LOG_DIRECTORY: Sets the directory for .NET Tracer logs.
Default: %ProgramData%\Datadog .NET Tracer\logs\
DD_TRACE_LOG_PATH: Sets the path for the automatic instrumentation log file and determines the directory of all other .NET Tracer log files. Ignored if DD_TRACE_LOG_DIRECTORY is set.
DD_TRACE_LOGGING_RATE: Sets rate limiting for log messages. If set, unique log lines are written once per x seconds. For example, to log a given message once per 60 seconds, set to 60. Setting to 0 disables log rate limiting. Added in version 1.24.0. Disabled by default.
DD_TRACE_SERVICE_MAPPING: Rename services using configuration. Accepts a map of service name keys to rename, and the name to use instead, in the format [from-key]:[to-name].
Example: mysql:main-mysql-db, mongodb:offsite-mongodb-service
The from-key value is specific to the integration type, and should exclude the application name prefix. For example, to rename my-application-sql-server to main-db, use sql-server:main-db. Added in version 1.23.0

Automatic instrumentation optional configuration

The following configuration variables are available only when using automatic instrumentation:

DD_TRACE_ENABLED: TracerSettings property: TraceEnabled
Enables or disables all automatic instrumentation. Setting the environment variable to false completely disables the CLR profiler. For other configuration methods, the CLR profiler is still loaded, but traces will not be generated. Valid values are: true or false.
Default: true
DD_HTTP_CLIENT_ERROR_STATUSES: Sets status code ranges that will cause HTTP client spans to be marked as errors.
Default: 400-499
DD_HTTP_SERVER_ERROR_STATUSES: Sets status code ranges that will cause HTTP server spans to be marked as errors.
Default: 500-599
DD_RUNTIME_METRICS_ENABLED: Enables .NET runtime metrics. Valid values are true or false.
Default: false
Added in version 1.23.0.
DD_TRACE_ADONET_EXCLUDED_TYPES: TracerSettings property: AdoNetExcludedTypes
Sets a list of AdoNet types (for example, System.Data.SqlClient.SqlCommand) that will be excluded from automatic instrumentation.

Automatic instrumentation integration configuration

The following table lists configuration variables that are available only when using automatic instrumentation and can be set for each integration.

DD_DISABLED_INTEGRATIONS: TracerSettings property: DisabledIntegrationNames
Sets a list of integrations to disable. All other integrations remain enabled. If not set, all integrations are enabled. Supports multiple values separated with semicolons. Valid values are the integration names listed in the Integrations section.
DD_TRACE_<INTEGRATION_NAME>_ENABLED: TracerSettings property: Integrations[<INTEGRATION_NAME>].Enabled
Enables or disables a specific integration. Valid values are: true or false. Integration names are listed in the Integrations section.
Default: true

Experimental features

The following configuration variables are for features that are available for use but may change in future releases.

DD_TRACE_ROUTE_TEMPLATE_RESOURCE_NAMES_ENABLED: Enables improved resource names for web spans when set to true. Uses route template information where available, adds an additional span for ASP.NET Core integrations, and enables additional tags. Added in version 1.26.0.
Default: false
DD_TRACE_PARTIAL_FLUSH_ENABLED: Enables incrementally flushing large traces to the Datadog Agent, reducing the chance of rejection by the Agent. Use only when you have long-lived traces or traces with many spans. Valid values are true or false. Added in version 1.26.0, only compatible with the Datadog Agent 7.26.0+.
Default: false