{beatname_uc} supports autodiscover based on hints from the provider. The `hints` system looks for
hints in Kubernetes Pod annotations or Docker labels which have the prefix `co.elastic.metrics`. As soon as
the container starts, {beatname_uc} will check if it contains any hints and launch the proper config for
it. Hints tell {beatname_uc} how to get metrics for the given container. This is the full list of supported hints:

[float]
===== `co.elastic.metrics/module`

{beatname_uc} module to use to fetch metrics. See <<metricbeat-modules>> for the list of supported modules.

[float]
===== `co.elastic.metrics/hosts`

Hosts setting to use with the given module. Hosts can include `${data.host}`, `${data.port}`,
`${data.ports.<port_name>}` values from the autodiscover event, ie: `${data.host}:80`.
For Kuberentes autodiscover events users can leverage port names as well,
like `http://${data.host}:${data.ports.prometheus}/metrics`.
In the last one we refer to the container port with name `prometheus`.

[float]
===== `co.elastic.metrics/metricsets`

List of metricsets to use, comma separated. If no metricsets are provided, default metricsets for the module
are used.

[float]
===== `co.elastic.metrics/metrics_path`

The path to retrieve the metrics from (/metrics by default) for <<prometheus-module>>.

[float]
===== `co.elastic.metrics/period`

The time interval for metrics retrieval, ie: 10s

[float]
===== `co.elastic.metrics/timeout`

Metrics retrieval timeout, default: 3s

[float]
===== `co.elastic.metrics/username`

The username to use for authentication

[float]
===== `co.elastic.metrics/password`

The password to use for authentication. It is recommended to retrieve this sensitive information from an ENV variable
and avoid placing passwords in plain text. Unlike static autodiscover configuration, hints based autodiscover has
no access to the keystore of Metricbeat since it could be a potential security issue. However hints based autodiscover
can make use of Kuberentes Secrets as described in <<kubernetes-secrets>>.

[float]
===== `co.elastic.metrics/ssl.*`

SSL parameters, as seen in <<configuration-ssl>>.

[float]
===== `co.elastic.metrics/raw`
When an entire module configuration needs to be completely set the `raw` hint can be used. You can provide a
stringified JSON of the input configuration. `raw` overrides every other hint and can be used to create both a single or
a list of configurations.

["source","yaml",subs="attributes"]
-------------------------------------------------------------------------------------
co.elastic.metrics/raw: "[{\"enabled\":true,\"metricsets\":[\"default\"],\"module\":\"mockmoduledefaults\",\"period\":\"1m\",\"timeout\":\"3s\"}]"
-------------------------------------------------------------------------------------

[float]
===== `co.elastic.metrics/processors`

Define a processor to be added to the {beatname_uc} module configuration. See <<filtering-and-enhancing-data>> for the list
of supported processors.

In order to provide ordering of the processor definition, numbers can be provided. If not, the hints builder will do
arbitrary ordering:

["source","yaml",subs="attributes"]
-------------------------------------------------------------------------------------
co.elastic.logs/processors.1.add_locale.abbrevation: "MST"
co.elastic.logs/processors.add_locale.abbrevation: "PST"
-------------------------------------------------------------------------------------

In the above sample the processor definition tagged with `1` would be executed first.

[float]
=== Kubernetes

Kubernetes autodiscover provider supports hints in Pod annotations. To enable it just set `hints.enabled`:

["source","yaml",subs="attributes"]
-------------------------------------------------------------------------------------
metricbeat.autodiscover:
  providers:
    - type: kubernetes
      hints.enabled: true
-------------------------------------------------------------------------------------

This configuration enables the `hints` autodiscover for Kubernetes. The `hints` system looks for
hints in Kubernetes annotations or Docker labels which have the prefix `co.elastic.metrics`.

You can annotate Kubernetes Pods with useful info to spin up {beatname_uc} modules:

["source","yaml",subs="attributes"]
-------------------------------------------------------------------------------------
annotations:
  co.elastic.metrics/module: prometheus
  co.elastic.metrics/metricsets: collector
  co.elastic.metrics/hosts: '${data.host}:9090'
  co.elastic.metrics/period: 1m
-------------------------------------------------------------------------------------

The above annotations are used to spin up a Prometheus collector metricset and it polls the
parent container on port `9090` at a 1 minute interval.

[float]
===== Multiple containers

When a Pod has multiple containers, these settings are shared. To set hints specific to a container in
the pod you can put the container name in the hint.

When a pod has multiple containers, the settings are shared unless you put the container name in the
hint. For example, these hints configure a common behavior for all containers in the Pod, and sets a specific
`hosts` hint for the container called `sidecar`.

["source","yaml",subs="attributes"]
-------------------------------------------------------------------------------------
annotations:
  co.elastic.metrics/module: apache
  co.elastic.metrics/hosts: '${data.host}:80'
  co.elastic.metrics.sidecar/hosts: '${data.host}:8080'
-------------------------------------------------------------------------------------

[float]
===== Multiple sets of hints
When a container port needs multiple modules to be defined on it, sets of annotations can be provided with numeric prefixes.
If there are hints that don't have a numeric prefix then they get grouped together into a single configuration.

["source","yaml",subs="attributes"]
-------------------------------------------------------------------------------------
annotations:
  co.elastic.metrics/1.module: prometheus
  co.elastic.metrics/1.hosts: '${data.host}:80/metrics'
  co.elastic.metrics/1.period: 60s
  co.elastic.metrics/module: prometheus
  co.elastic.metrics/hosts: '${data.host}:80/metrics/p1'
  co.elastic.metrics/period: 5s
-------------------------------------------------------------------------------------

The above configuration would spin up two metricbeat module configurations to ensure that the endpoint "/metrics/p1" is
polled every 60s whereas the "/metrics" endpoint is polled every 60s.

[float]
===== Configuring Namespace Defaults

Hints can be configured on the Namespace's annotations as defaults to use when Pod level annotations are missing.
The resultant hints are a combination of Pod annotations and Namespace annotations with the Pod's taking precedence. To
enable Namespace defaults configure the `add_resource_metadata` for Namespace objects as follows:

["source","yaml",subs="attributes"]
-------------------------------------------------------------------------------------
metricbeat.autodiscover:
  providers:
    - type: kubernetes
      hints.enabled: true
      add_resource_metadata:
        namespace:
          enabled: true
-------------------------------------------------------------------------------------


[float]
=== Docker

Docker autodiscover provider supports hints in labels. To enable it just set `hints.enabled`:

["source","yaml",subs="attributes"]
-------------------------------------------------------------------------------------
metricbeat.autodiscover:
  providers:
    - type: docker
      hints.enabled: true
-------------------------------------------------------------------------------------

You can label Docker containers with useful info to spin up {beatname_uc} modules, for example:

["source","yaml",subs="attributes"]
-------------------------------------------------------------------------------------
  co.elastic.metrics/module: nginx
  co.elastic.metrics/metricsets: stubstatus
  co.elastic.metrics/hosts: '${data.host}:80'
  co.elastic.metrics/period: 10s
-------------------------------------------------------------------------------------

The above labels would allow {beatname_uc} to run the nginx module and poll port `80`
of the Docker container every 10 seconds.
