[[configuration-autodiscover]]
== Autodiscover

Autodiscover allows you to watch for system changes and dynamically adapt settings to them, as they happen.
This is specially useful when running your infrastructure on containers.

When you run an application on containers it becomes a moving target to the monitoring system. Autodiscover
allows you to automatically detect what's running and update settings to monitor it.

You can define configuration templates for different containers. Autodiscover subsystem will use them
to monitor services as they start running.

You define autodiscover settings in the  +{beatname_lc}.autodiscover+ section of the +{beatname_lc}.yml+
config file. To enable autodiscover, you specify a list of providers.

[float]
=== Providers

Autodiscover providers work by watching for events on the system and translating those events into internal autodiscover
events with a common format. When you configure the provider, you can use fields from the autodiscover event to set
conditions that, when met, launch specific configurations.

[float]
===== Docker

Docker autodiscover provider watches for Docker containers start and stop. These are the available fields on every
event:

  * host
  * port
  * docker.container.id
  * docker.container.image
  * docker.container.name
  * docker.container.labels


For example:

[source,yaml]
-------------------------------------------------------------------------------------
{
  "host": "10.4.15.9",
  "port": 6379,
  "docker": {
    "container": {
      "id": "382184ecdb385cfd5d1f1a65f78911054c8511ae009635300ac28b4fc357ce51"
      "name": "redis",
      "image": "redis:3.2.11",
      "labels": {
        "io.kubernetes.pod.namespace": "default"
        ...
      }
    }
  }
}
-------------------------------------------------------------------------------------

You can define a set of configuration templates to be applied when the condition matches an event. Templates define
a condition to match on autodiscover events, together with the list of configurations to launch when this condition
happens.

Conditions match events from the provider. Providers use the same format for <<conditions>> that
processors use.

Configuration templates can contain variables from the autodiscover event. They can be accessed under `data` namespace.
For example, with the example event, "`${data.port}`" will resolves to `6379`.

include::../../{beatname_lc}/docs/autodiscover-docker-config.asciidoc[]