Install DataDog Agent as a docker container

November 23, 2018 — 2 Min Read

DataDog is a monitoring service for cloud-scale applications, in the following guide we’ll see how to create a docker container with the DataDog agent and how to use it to publish custom metrics.

Requirements

In the following article we assume that yuo have:

a DataDog account with a valid API key; you can get the key from Integrations > API;
Docker installed.

Setup docker container

As first thing, we create an environment variable that we’ll use to pass the API key to the docker container:

DD_API_KEY=<API_KEY>

Then we run the container with the agent with:

docker run --rm -d -v /var/run/docker.sock:/var/run/docker.sock:ro -v /proc/:/host/proc/:ro -v /sys/fs/cgroup/:/host/sys/fs/cgroup:ro -e DD_API_KEY=$DD_API_KEY --name dd-agent datadog/agent:latest

The previous command should be enough for the most common cases, but if for specific reasons you need to send metrics from your host machine to the DataDog agent, you should run the following:

$ docker run \
  --rm \
  -d \
  -v /var/run/docker.sock:/var/run/docker.sock:ro \
  -v /proc/:/host/proc/:ro \
  -v /sys/fs/cgroup/:/host/sys/fs/cgroup:ro \
  -e DD_API_KEY=$DD_API_KEY \
  -e DD_DOGSTATSD_NON_LOCAL_TRAFFIC=true \
  -p 8125:8125/udp \
  --name dd-agent \
  datadog/agent:latest

This way the container port is exposed to the local machine.

You can refer to the official documentation for more specific configurations.

Test the agent

In order to test if the agent works properly we’re going to send a custom metric from the command line.

If the container exposes the port to the host, it is possible to use one the following:

# Linux
echo -n "custom_metric:20|g|#shell" > /dev/udp/localhost/8125
# macOS
echo -n "custom_metric:20|g|#shell" | nc -4u -w0 localhost 8125

It is also possible to send a metric from within the container itself:

# open a shell in the container
docker exec -i -t dd-agent /bin/bash

# send the custom metrics using the container's shell
echo -n "custom_metric:20|g|#shell" > /dev/udp/localhost/8125