Autodiscover

Autodiscover allows you to watch for system changes and dynamically adapt settings to them, as they happen. This is especially 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. The autodiscover subsystem will use them to monitor services as they start running.

You define autodiscover settings in the metricbeat.autodiscover section of the metricbeat.yml config file. To enable autodiscover, you specify a list of 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.

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

For example:

{
  "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 the data namespace. For example, with the example event, "${data.port}" resolves to 6379.

Metricbeat supports templates for modules:

metricbeat.autodiscover:
  providers:
    - type: docker
      templates:
        - condition:
            contains:
              docker.container.image: "redis"
          config:
            - module: redis
              metricsets: ["info", "keyspace"]
              hosts: "${data.host}:6379"

This configuration launches a redis module for all containers running an image with redis in the name.

The Kubernetes autodiscover provider watches for Kubernetes pods to start, update, and stop. These are the available fields on every event:

If the include_annotations config is added to the provider config, then the list of annotations present in the config are added to the event.

For example:

{
  "host": "172.17.0.21",
  "port": 9090,
  "kubernetes": {
    "container": {
      "id": "bb3a50625c01b16a88aa224779c39262a9ad14264c3034669a50cd9a90af1527",
      "image": "prom/prometheus",
      "name": "prometheus"
    },
    "labels": {
      "project": "prometheus",
      ...
    },
    "namespace": "default",
    "node": {
      "name": "minikube"
    },
    "pod": {
      "name": "prometheus-2657348378-k1pnh"
    }
  },
}

The configuration of templates and conditions is similar to that of the Docker provider. Configuration templates can contain variables from the autodiscover event. They can be accessed under data namespace.

Metricbeat supports templates for modules:

metricbeat.autodiscover:
  providers:
    - type: kubernetes
      include_annotations: ["prometheus.io.scrape"]
      templates:
        - condition:
            contains:
              kubernetes.annotations.prometheus.io.scrape: "true"
          config:
            - module: prometheus
              metricsets: ["collector"]
              hosts: "${data.host}:{data.port}"

This configuration launches a prometheus module for all containers of pods annotated prometheus.io.scrape=true.