Datadog Nginx Tracing Playground

Why

I want to verify that nginx can be installed, operated, and traced using Datadog on a variety of Linux distributions.

What

This is a docker-compose setup that installs and runs the most recent open source release of nginx on a specified base image, and then stands up the Datadog agent and a downstream web server.

Query http://localhost:8080 and http://localhost:8080/downstream from the host machine, and then search the Datadog UI for traces having service:test_playground_nginx.

How

$ bin/run --help
nginx tracing playground

usage:
    DD_API_KEY=KEY bin/run IMAGE
        Install nginx on the specified Docker base IMAGE, and bring up nginx along with
        the Datadog agent and a downstream web server, all accessible on port
        8080 of the host.  Use the specified KEY to authenticate the Datadog agent.

    bin/run --help
    bin/run -h
        Print this message.

$ DD_API_KEY=<REDACTED> bin/run ubuntu:18.04 &
... lots of output ...

$ curl http://localhost:8080/downstream
You hit the node script, congrats. Here are your headers:

{
  "x-datadog-trace-id": "3536317360567308007",
  "x-datadog-parent-id": "3536317360567308007",
  "x-datadog-sampling-priority": "1",
  "host": "downstream:8080",
  "connection": "close",
  "user-agent": "curl/7.74.0",
  "accept": "*/*"
}

$ kill %1

Then a Datadog search for traces using the service:test_playground_nginx filter shows something like:

More

Dependencies

• docker-compose
• docker

Known to Work

The following base images have been tested using this docker-compose setup and are known to work:

• centos:7 (unexpected, but it works for this setup)
• centos:8
• ubuntu:18.04
• ubuntu:20.04
• debian:buster
• debian:bullseye
• opensuse/leap:15.2

Known to Fail

The following base image has been tested using this docker-compose setup and is known not to work:

• alpine:3 (see the note about glibc in nginx/setup-base-apk.sh)

Repository Layout

• assets/ contains images used in this readme file.
• bin/ contains the run script, which is a wrapper around docker-compose.
• downstream/ contains the definition of a docker image for a node.js web server, which is to be reverse proxied by nginx.
• nginx contains the definition of a docker image for a recent version of nginx running on a specified Linux distribution.
• docker-compose.yml combines the above elements.