NGINX Native OpenTelemetry (OTel) Module

What is OpenTelemetry

OpenTelemetry (OTel) is an observability framework for monitoring, tracing, troubleshooting, and optimizing applications. OTel enables the collection of telemetry data from a deployed application stack.

What is the NGINX Native OTel Module

The ngx_otel_module dynamic module enables NGINX Open-Source or NGINX Plus to send telemetry data to an OTel collector. It provides support for W3C trace context propagation, OTLP/gRPC trace exports and offers several benefits over exiting OTel modules, including:

Better Performance

3rd-party OTel implementations reduce performance of request processing by as much as 50% when tracing is enabled. The NGINX Native module limits this impact to approximately 10-15%.

Easy Provisioning

Setup and configuration can be done right in NGINX configuration files.

Fully Dynamic Variable-Based Sampling

The module provides the ability to trace a particular session by cookie/token. Additionally, NGINX Plus, available as part of a commercial subscription, enables dynamic module control via the NGINX Plus API and key-value store modules.

Building

Follow these steps to build the ngx_otel_module dynamic module on Ubuntu or Debian based systems:

Install build tools and dependencies.

sudo apt install cmake build-essential libssl-dev zlib1g-dev libpcre3-dev
sudo apt install pkg-config libc-ares-dev libre2-dev # for gRPC

For the next step, you will need the configure script that is packaged with the NGINX source code. There are several methods for obtaining NGINX sources. You may choose to download them or clone them directly from the NGINX Github repository.

Important: To ensure compatibility, the ngx_otel_module and the NGINX binary that it will be used with, will need to be built using the same NGINX source code and operating system. We will build and install NGINX from obtained sources in a later step. When obtaining NGINX sources from Github, please ensure that you switch to the branch that you intend to use with the module binary. For simplicity, we will assume that the main branch will be used for the remainder of this tutorial.

git clone https://github.com/nginx/nginx.git

Configure NGINX to generate files necessary for dynamic module compilation. These files will be placed into the nginx/objs directory.

Important: If you did not obtain NGINX source code via the clone method in the previous step, you will need to adjust paths in the following commands to conform to your specific directory structure.

cd nginx
auto/configure --with-compat

Exit the NGINX directory and clone the ngx_otel_module repository.

cd ..
git clone https://github.com/nginxinc/nginx-otel.git

Configure and build the NGINX OTel module.

Important: replace the path in the cmake command with the path to the nginx/objs directory from above.

cd nginx-otel
mkdir build
cd build
cmake -DNGX_OTEL_NGINX_BUILD_DIR=/path/to/configured/nginx/objs ..
make

Compilation will produce a binary named ngx_otel_module.so.

Installation

Important: The built ngx_otel_module.so dynamic module binary will ONLY be compatible with the same version of NGINX source code that was used to build it. To guarantee proper operation, you will need to build and install NGINX from sources obtained in previous steps on the same operating system.

Follow instructions related to compiling and installing NGINX. Skip procedures for downloading source code.

By default, this will install NGINX into /usr/local/nginx. The following steps assume this directory structure.

Copy the ngx_otel_module.so dynamic module binary to /usr/local/nginx/modules.

Load the module by adding the following line to the top of the main NGINX configuration file, located at: /usr/local/nginx/conf/nginx.conf.

load_module modules/ngx_otel_module.so;

Configuring the Module

For a complete list of directives, embedded variables, default span attributes and sample configurations, please refer to the ngx_otel_module documentation.

Examples

Use these examples to configure some common use-cases for OTel tracing.

Simple Tracing

This example sends telemetry data for all http requests.

http {
    otel_trace on;
    server {
        location / {
            proxy_pass http://backend;
        }
    }
}

Parent-based Tracing

In this example, we inherit trace contexts from incoming requests and record spans only if a parent span is sampled. We also propagate trace contexts and sampling decisions to upstream servers.

http {
    server {
        location / {
            otel_trace $otel_parent_sampled;
            otel_trace_context propagate;

            proxy_pass http://backend;
        }
    }
}

Ratio-based Tracing

In this ratio-based example, tracing is configured for a percentage of traffic (in this case 10%):

http {
    # trace 10% of requests
    split_clients $otel_trace_id $ratio_sampler {
        10%     on;
        *       off;
    }

    # or we can trace 10% of user sessions
    split_clients $cookie_sessionid $session_sampler {
        10%     on;
        *       off;
    }

    server {
        location / {
            otel_trace $ratio_sampler;
            otel_trace_context inject;

            proxy_pass http://backend;
        }
    }
}

Collecting and Viewing Traces

There are several methods and available software packages for viewing traces. For a quick start, Jaeger provides an all-in-one container to collect, process and view OTel trace data. Follow these steps to download, install, launch and use Jaeger's OTel services.

Community

• Our Slack channel #nginx-opentelemetry-module, is the go-to place to start asking questions and sharing your thoughts.

• Our GitHub issues page offers space for a more technical discussion at your own pace.

Contributing

Get involved with the project by contributing! Please see our contributing guide for details.

Change Log

See our release page to keep track of updates.

License

Apache License, Version 2.0

© F5, Inc. 2023