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General availability (GA) Open source

discovery.marathon

discovery.marathon allows you to retrieve scrape targets from Marathon’s Service API.

Usage

Alloy 
discovery.marathon "<LABEL>" {
  servers = ["<MARATHON_SERVER1>", "<MARATHON_SERVER2>"...]
}

Arguments

You can use the following arguments with discovery.marathon:

NameTypeDescriptionDefaultRequired
serverslist(string)List of Marathon servers.yes
auth_token_filestringFile containing an auth token to authenticate with.no
auth_tokensecretAuth token to authenticate with.no
bearer_token_filestringFile containing a bearer token to authenticate with.no
bearer_tokensecretBearer token to authenticate with.no
enable_http2boolWhether HTTP2 is supported for requests.trueno
follow_redirectsboolWhether redirects returned by the server should be followed.trueno
http_headersmap(list(secret))Custom HTTP headers to be sent along with each request. The map key is the header name.no
no_proxystringComma-separated list of IP addresses, CIDR notations, and domain names to exclude from proxying.no
proxy_connect_headermap(list(secret))Specifies headers to send to proxies during CONNECT requests.no
proxy_from_environmentboolUse the proxy URL indicated by environment variables.falseno
proxy_urlstringHTTP proxy to send requests through.no
refresh_intervaldurationInterval at which to refresh the list of targets."30s"no

At most, one of the following can be provided:

no_proxy can contain IPs, CIDR notations, and domain names. IP and domain names can contain port numbers. proxy_url must be configured if no_proxy is configured.

proxy_from_environment uses the environment variables HTTP_PROXY, HTTPS_PROXY, and NO_PROXY (or the lowercase versions thereof). Requests use the proxy from the environment variable matching their scheme, unless excluded by NO_PROXY. proxy_url and no_proxy must not be configured if proxy_from_environment is configured.

proxy_connect_header should only be configured if proxy_url or proxy_from_environment are configured.

Blocks

You can use the following blocks with discovery.marathon:

BlockDescriptionRequired
authorizationConfigure generic authorization to the endpoint.no
basic_authConfigure basic_auth for authenticating to the endpoint.no
oauth2Configure OAuth 2.0 for authenticating to the endpoint.no
oauth2 > tls_configConfigure TLS settings for connecting to the endpoint.no
tls_configConfigure 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.

authorization

The authorization block configures generic authorization to the endpoint.

NameTypeDescriptionDefaultRequired
credentials_filestringFile containing the secret value.no
credentialssecretSecret value.no
typestringAuthorization type, for example, “Bearer”.no

credential and credentials_file are mutually exclusive, and only one can be provided inside an authorization block.

Warning

Using credentials_file causes the file to be read on every outgoing request. Use the local.file component with the credentials attribute instead to avoid unnecessary reads.

basic_auth

The basic_auth block configures basic authentication to the endpoint.

NameTypeDescriptionDefaultRequired
password_filestringFile containing the basic auth password.no
passwordsecretBasic auth password.no
usernamestringBasic auth username.no

password and password_file are mutually exclusive, and only one can be provided inside a basic_auth block.

Warning

Using password_file causes the file to be read on every outgoing request. Use the local.file component with the password attribute instead to avoid unnecessary reads.

oauth2

The oauth block configures OAuth 2.0 authentication to the endpoint.

NameTypeDescriptionDefaultRequired
client_idstringOAuth2 client ID.no
client_secret_filestringFile containing the OAuth2 client secret.no
client_secretsecretOAuth2 client secret.no
endpoint_paramsmap(string)Optional parameters to append to the token URL.no
no_proxystringComma-separated list of IP addresses, CIDR notations, and domain names to exclude from proxying.no
proxy_connect_headermap(list(secret))Specifies headers to send to proxies during CONNECT requests.no
proxy_from_environmentboolUse the proxy URL indicated by environment variables.falseno
proxy_urlstringHTTP proxy to send requests through.no
scopeslist(string)List of scopes to authenticate with.no
token_urlstringURL to fetch the token from.no

client_secret and client_secret_file are mutually exclusive, and only one can be provided inside an oauth2 block.

Warning

Using client_secret_file causes the file to be read on every outgoing request. Use the local.file component with the client_secret attribute instead to avoid unnecessary reads.

The oauth2 block may also contain a separate tls_config sub-block.

no_proxy can contain IPs, CIDR notations, and domain names. IP and domain names can contain port numbers. proxy_url must be configured if no_proxy is configured.

proxy_from_environment uses the environment variables HTTP_PROXY, HTTPS_PROXY, and NO_PROXY (or the lowercase versions thereof). Requests use the proxy from the environment variable matching their scheme, unless excluded by NO_PROXY. proxy_url and no_proxy must not be configured if proxy_from_environment is configured.

proxy_connect_header should only be configured if proxy_url or proxy_from_environment are configured.

tls_config

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

NameTypeDescriptionDefaultRequired
ca_pemstringCA PEM-encoded text to validate the server with.no
ca_filestringCA certificate to validate the server with.no
cert_pemstringCertificate PEM-encoded text for client authentication.no
cert_filestringCertificate file for client authentication.no
insecure_skip_verifyboolDisables validation of the server certificate.no
key_filestringKey file for client authentication.no
key_pemsecretKey PEM-encoded text for client authentication.no
min_versionstringMinimum acceptable TLS version.no
server_namestringServerName extension to indicate the name of the server.no

The following pairs of arguments are mutually exclusive and can’t both be set simultaneously:

  • ca_pem and ca_file
  • cert_pem and cert_file
  • key_pem and key_file

When configuring client authentication, both the client certificate (using cert_pem or cert_file) and the client key (using key_pem or key_file) must be provided.

When min_version isn’t provided, the minimum acceptable TLS version is inherited from Go’s default minimum version, TLS 1.2. If min_version is provided, it must be set to one of the following strings:

  • "TLS10" (TLS 1.0)
  • "TLS11" (TLS 1.1)
  • "TLS12" (TLS 1.2)
  • "TLS13" (TLS 1.3)

Exported fields

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

NameTypeDescription
targetslist(map(string))The set of targets discovered from the Marathon servers.

Each target includes the following labels:

  • __meta_marathon_app_label_<labelname>: Any Marathon labels attached to the app.
  • __meta_marathon_app: The name of the app, with slashes replaced by dashes.
  • __meta_marathon_image: The name of the Docker image used, if available.
  • __meta_marathon_port_definition_label_<labelname>: The port definition labels.
  • __meta_marathon_port_index: The port index number, for example 1 for PORT1.
  • __meta_marathon_port_mapping_label_<labelname>: The port mapping labels.
  • __meta_marathon_task: The ID of the Apache Mesos task.

Component health

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

Debug information

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

Debug metrics

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

Example

This example discovers targets from a Marathon server:

Alloy 
discovery.marathon "example" {
  servers = ["localhost:8500"]
}

prometheus.scrape "demo" {
  targets    = discovery.marathon.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.marathon has exports that can be consumed by the following components:

Note

Connecting some components may not be sensible or components may require further configuration to make the connection work correctly. Refer to the linked documentation for more details.