Documentation Grafana Alloy Reference Components discovery discovery.docker

discovery.docker

discovery.docker discovers Docker Engine containers and exposes them as targets.

Usage

Alloy Copy

discovery.docker "<LABEL>" {
  host = "<DOCKER_ENGINE_HOST>"
}

Arguments

You can use the following arguments with discovery.docker:

At most, one of the following can be provided:

• authorization block
• basic_auth block
• bearer_token_file argument
• bearer_token argument
• oauth2 block

Blocks

You can use the following blocks with discovery.docker:

The > symbol indicates deeper levels of nesting. For example, oauth2 > tls_config refers to a tls_config block defined inside an oauth2 block.

authorization

The authorization block configures generic authorization to the endpoint.

basic_auth

The basic_auth block configures basic authentication to the endpoint.

filter

The filter block configures a filter to pass to the Docker Engine to limit the number of containers returned. You can specify the filter block multiple times to provide more than one filter.

Refer to List containers from the Docker Engine API documentation for the list of supported filters and their meaning.

oauth2

The oauth2 block configures OAuth 2.0 authentication to the endpoint.

tls_config

The tls_config block configures TLS settings for connecting to the endpoint.

Exported fields

The following fields are exported and can be referenced by other components:

Each target includes the following labels:

• __meta_docker_container_id: ID of the container.
• __meta_docker_container_label_<labelname>: Each label from the container.
• __meta_docker_container_name: Name of the container.
• __meta_docker_container_network_mode: Network mode of the container.
• __meta_docker_network_id: ID of the Docker network the container is in.
• __meta_docker_network_ingress: Set to true if the Docker network is an ingress network.
• __meta_docker_network_internal: Set to true if the Docker network is an internal network.
• __meta_docker_network_ip: The IP of the container in the network.
• __meta_docker_network_label_<labelname>: Each label from the network the container is in.
• __meta_docker_network_name: Name of the Docker network the container is in.
• __meta_docker_network_scope: The scope of the network the container is in.
• __meta_docker_port_private: The private port on the container.
• __meta_docker_port_public_ip: The public IP of the container, if a port mapping exists.
• __meta_docker_port_public: The publicly exposed port from the container, if a port mapping exists.

Each discovered container maps to one target per unique combination of networks and port mappings used by the container.

Component health

discovery.docker is only reported as unhealthy when given an invalid configuration. In those cases, exported fields retain their last healthy values.

Debug information

discovery.docker doesn’t expose any component-specific debug information.

Debug metrics

discovery.docker doesn’t expose any component-specific debug metrics.

Examples

Linux or macOS hosts

This example discovers Docker containers when the host machine is macOS or Linux:

Alloy Copy

discovery.docker "containers" {
  host = "unix:///var/run/docker.sock"
}

prometheus.scrape "demo" {
  targets    = discovery.docker.containers.targets
  forward_to = [prometheus.remote_write.demo.receiver]
}

prometheus.remote_write "demo" {
  endpoint {
    url = "<PROMETHEUS_REMOTE_WRITE_URL>"

    basic_auth {
      username = "<USERNAME>"
      password = "<PASSWORD>"
    }
  }
}

Replace the following:

• <PROMETHEUS_REMOTE_WRITE_URL>: The URL of the Prometheus remote_write-compatible server to send metrics to.
• <USERNAME>: The username to use for authentication to the remote_write API.
• <PASSWORD>: The password to use for authentication to the remote_write API.

Windows hosts

This example discovers Docker containers when the host machine is Windows:

Alloy Copy

discovery.docker "containers" {
  host = "tcp://localhost:2375"
}

prometheus.scrape "demo" {
  targets    = discovery.docker.containers.example.targets
  forward_to = [prometheus.remote_write.demo.receiver]
}

prometheus.remote_write "demo" {
  endpoint {
    url = "<PROMETHEUS_REMOTE_WRITE_URL>"

    basic_auth {
      username = "<USERNAME>"
      password = "<PASSWORD>"
    }
  }
}

Replace the following:

• <PROMETHEUS_REMOTE_WRITE_URL>: The URL of the Prometheus remote_write-compatible server to send metrics to.
• <USERNAME>: The username to use for authentication to the remote_write API.
• <PASSWORD>: The password to use for authentication to the remote_write API.

Compatible components

discovery.docker has exports that can be consumed by the following components:

• Components that consume Targets