Autodiscover

When you run applications on containers, they become moving targets to the monitoring system. Autodiscover allows you to track them and adapt settings as changes happen. By defining configuration templates, the autodiscover subsystem can 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 optionally use fields from the autodiscover event to set conditions that, when met, launch specific configurations.

On start, Metricbeat will scan existing containers and launch the proper configs for them. Then it will watch for new start/stop events. This ensures you don’t need to worry about state, but only define your desired configs.

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.

The kubernetes autodiscover provider has the following configuration settings:

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.

Declare exposed ports in your pod spec if possible. Otherwise, you will need to use multiple templates with complex filtering rules. The {port} variable will not be present, and you will need to hardcode ports. Example: {data.host}:1234

When ports are not declared, Autodiscover generates a config using your provided template once per pod, and once per container. These generated configs are de-duplicated after they are generated. If the generated configs for multiple containers are identical, they will be merged into one config.

Pods share an identical host. If only the {data.host} variable is interpolated, then one config will be generated per host. The configs will be identical. After they are de-duplicated, only one will be used.

The Jolokia autodiscover provider uses Jolokia Discovery to find agents running in your host or your network.

Jolokia Discovery mechanism is supported by any Jolokia agent since version 1.2.0, it is enabled by default when Jolokia is included in the application as a JVM agent, but disabled in other cases as the OSGI or WAR (Java EE) agents. In any case, this feature is controlled with two properties:

There are multiple ways of setting these properties, and they can vary from application to application, please refer to the documentation of your application to find the more suitable way to set them in your case.

Jolokia Discovery is based on UDP multicast requests. Agents join the multicast group 239.192.48.84, port 24884, and discovery is done by sending queries to this group. You have to take into account that UDP traffic between Metricbeat and the Jolokia agents has to be allowed. Also notice that this multicast address is in the 239.0.0.0/8 range, that is reserved for private use within an organization, so it can only be used in private networks.

These are the available fields on every event:

The configuration of this provider consists in a set of network interfaces, as well as a set of templates as in other providers. The network interfaces will be the ones used for discovery probes, they have these settings:

Metricbeat supports templates for modules:

metricbeat.autodiscover:
  providers:
    - type: jolokia
      interfaces:
      - name: br*
        interval: 5s
        grace_period: 10s
      - name: en*
      templates:
      - condition:
          contains:
            jolokia.server.product: "tomcat"
        config:
        - module: jolokia
          metricsets: ["jmx"]
          hosts: "${data.jolokia.url}"
          namespace: test
          jmx.mappings:
          - mbean: "java.lang:type=Runtime"
            attributes:
            - attr: Uptime
              field: uptime

This configuration starts a jolokia module that collects the uptime of each tomcat instance discovered. Discovery probes are sent using all interfaces starting with br and en, for the br interfaces the interval and grace_period is reduced to 5 and 10 seconds respectively.