discovery.docker.md

---

title: discovery.docker

---

discovery.docker

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

Usage

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

Arguments

The following arguments are supported:

Name	Type	Description	Default	Required
host	string	Address of the Docker Daemon to connect to.		yes
port	number	Port to use for collecting metrics when containers don't have any port mappings.	80	no
host_networking_host	string	Host to use if the container is in host networking mode.	"localhost"	no
refresh_interval	duration	Frequency to refresh list of containers.	"1m"	no
bearer_token	secret	Bearer token to authenticate with.		no
bearer_token_file	string	File containing a bearer token to authenticate with.		no
proxy_url	string	HTTP proxy to proxy requests through.		no
follow_redirects	bool	Whether redirects returned by the server should be followed.	true	no
enable_http2	bool	Whether HTTP2 is supported for requests.	true	no

At most one of the following can be provided:

• bearer_token argument.

• bearer_token_file argument.

• basic_auth block.

• authorization block.

• oauth2 block.

Blocks

The following blocks are supported inside the definition of discovery.docker:

Hierarchy	Block	Description	Required
filter	filter	Filters discoverable resources.	no
basic_auth	basic_auth	Configure basic_auth for authenticating to the endpoint.	no
authorization	authorization	Configure generic authorization to the endpoint.	no
oauth2	oauth2	Configure OAuth2 for authenticating to the endpoint.	no
oauth2 > tls_config	tls_config	Configure TLS settings for connecting to the endpoint.	no

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

filter block

The filter block configures a filter to pass to the Docker Engine to limit the amount of containers returned. The filter block can be specified multiple times to provide more than one filter.

Name	Type	Description	Default	Required
name	string	Filter name to use.		yes
values	list(string)	Values to pass to the filter.		yes

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

basic_auth block

{{< docs/shared lookup="flow/reference/components/basic-auth-block.md" source="agent" >}}

authorization block

{{< docs/shared lookup="flow/reference/components/authorization-block.md" source="agent" >}}

oauth2 block

{{< docs/shared lookup="flow/reference/components/oauth2-block.md" source="agent" >}}

tls_config block

{{< docs/shared lookup="flow/reference/components/tls-config-block.md" source="agent" >}}

Exported fields

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

Name	Type	Description
targets	list(map(string))	The set of targets discovered from the docker API.

Each target includes the following labels:

• __meta_docker_container_id: ID of the container.

• __meta_docker_container_name: Name of the container.

• __meta_docker_container_network_mode: Network mode of the container.

• __meta_docker_container_label_<labelname>: Each label from the container.

• __meta_docker_network_id: ID of the Docker network the container is in.

• __meta_docker_network_name: Name 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_label_<labelname>: Each label from the network the container is in.

• __meta_docker_network_scope: The scope of the network the container is in.

• __meta_docker_network_ip: The IP of the container in the network.

• __meta_docker_port_private: The private port on the container.

• __meta_docker_port_public: The publicly exposed port from the container, if a port mapping exists.

• __meta_docker_port_public_ip: The public IP of 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 does not expose any component-specific debug information.

Debug metrics

discovery.docker does not expose any component-specific debug metrics.

Examples

Linux or macOS hosts

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

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

Windows hosts

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

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

NOTE: This example requires the "Expose daemon on tcp://localhost:2375 without TLS" setting to be enabled in the Docker Engine settings.