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Last pushed: 3 days ago
Short Description
Telegraf is an agent for collecting metrics and writing them to InfluxDB or other outputs.
Full Description

Supported tags and respective Dockerfile links

(amd64/telegraf build job)

Quick reference

Telegraf

Telegraf is an open source agent written in Go for collecting metrics and data on the system it's running on or from other services. Telegraf writes data it collects to InfluxDB in the correct format.

Telegraf Official Docs

Using this image

Exposed Ports

  • 8125 StatsD
  • 8092 UDP
  • 8094 TCP

Using the default configuration

The default configuration requires a running InfluxDB instance as an output plugin. Ensure that InfluxDB is running on port 8086 before starting the Telegraf container.

Minimal example to start an InfluxDB container:

$ docker run -d --name influxdb -p 8083:8083 -p 8086:8086 influxdb

Starting Telegraf using the default config, which connects to InfluxDB at http://localhost:8086/:

$ docker run --net=container:influxdb telegraf

Using a custom config file

First, generate a sample configuration and save it as telegraf.conf on the host:

$ docker run --rm telegraf -sample-config > telegraf.conf

Once you've customized telegraf.conf, you can run the Telegraf container with it mounted in the expected location:

$ docker run -v $PWD/telegraf.conf:/etc/telegraf/telegraf.conf:ro telegraf

Modify $PWD to the directory where you want to store the configuration file.

Read more about the Telegraf configuration here.

Using the container with input plugins

These examples assume you are using a custom configuration file that takes advantage of Docker's built-in service discovery capability. In order to do so, we'll first create a new network:

$ docker network create influxdb

Next, we'll start our InfluxDB container named influxdb:

$ docker run -d --name=influxdb \
      --net=influxdb \
      influxdb

The telegraf.conf configuration can now resolve the influxdb container by name:

[[outputs.influxdb]]
    urls = ["http://influxdb:8086"]

Finally, we start our Telegraf container and verify functionality:

$ docker run -d --name=telegraf \
      --net=influxdb \
      -v $PWD/telegraf.conf:/etc/telegraf/telegraf.conf:ro \
      telegraf
$ docker logs -f telegraf

Aerospike

Start an instance of aerospike:

$ docker run -d --name aerospike \
      --net=influxdb \
      -p 3000-3003:3000-3003 \
      aerospike

Edit your Telegraf config file and set the correct connection parameter for Aerospike:

[[inputs.aerospike]]
    servers = ["aerospike:3000"]

Restart your telegraf container to pick up the changes:

$ docker restart telegraf

Nginx

Create an nginx_status.conf configuration file to expose metric data:

server {
    listen 8090;
    location /nginx_status {
        stub_status on;
        access_log on;
    }
}

Start an Nginx container utilizing it:

$ docker run -d --name=nginx \
      --net=influxdb \
      -p 8090:8090 -p 8080:80 \
      -v $PWD/nginx_status.conf:/etc/nginx/conf.d/nginx_status.conf:ro \
      nginx

Verify the status page: http://localhost:8090/nginx_status.

Configure the nginx input plugin in your Telegraf configuration file:

[[inputs.nginx]]
  urls = ["http://nginx:8090/nginx_status"]

Restart your telegraf container to pick up the changes:

$ docker restart telegraf

StatsD

Telegraf has a StatsD plugin, allowing Telegraf to run as a StatsD server that metrics can be sent to. In order for this to work, you must first configure the StatsD plugin in your config file.

Run Telegraf with the UDP port 8125 exposed:

$ docker run -d --name=telegraf \
      --net=influxdb \
      -p 8125:8125/udp \
      -v $PWD/telegraf.conf:/etc/telegraf/telegraf.conf:ro \
      telegraf

Send Mock StatsD data:

$ for i in {1..50}; do echo $i;echo "foo:1|c" | nc -u -w0 127.0.0.1 8125; done

Check that the measurement foo is added in the DB.

Supported Plugins Reference

Image Variants

The amd64/telegraf images come in many flavors, each designed for a specific use case.

amd64/telegraf:<version>

This is the defacto image. If you are unsure about what your needs are, you probably want to use this one. It is designed to be used both as a throw away container (mount your source code and start the container to start your app), as well as the base to build other images off of.

amd64/telegraf:alpine

This image is based on the popular Alpine Linux project, available in the alpine official image. Alpine Linux is much smaller than most distribution base images (~5MB), and thus leads to much slimmer images in general.

This variant is highly recommended when final image size being as small as possible is desired. The main caveat to note is that it does use musl libc instead of glibc and friends, so certain software might run into issues depending on the depth of their libc requirements. However, most software doesn't have an issue with this, so this variant is usually a very safe choice. See this Hacker News comment thread for more discussion of the issues that might arise and some pro/con comparisons of using Alpine-based images.

To minimize image size, it's uncommon for additional related tools (such as git or bash) to be included in Alpine-based images. Using this image as a base, add the things you need in your own Dockerfile (see the alpine image description for examples of how to install packages if you are unfamiliar).

License

View license information for the software contained in this image.

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