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Grafana Agent Flow mode Reference Components reference discovery.nomad
Open source

discovery.consul

discovery.nomad allows you to retrieve scrape targets from Nomad’s Service API.

Usage

river 
discovery.nomad "LABEL" {
  server = NOMAD_SERVER
}

Arguments

The following arguments are supported:

NameTypeDescriptionDefaultRequired
serverstringAddress of nomad server.http://localhost:4646no
namespacestringNomad namespace to use.defaultno
regionstringNomad region to use.globalno
allow_staleboolAllow reading from non-leader nomad instances.trueno
tag_separatorstringSeperator to join nomad tags into Prometheus labels.,no
refresh_intervaldurationFrequency to refresh list of containers."30s"no
bearer_tokensecretBearer token to authenticate with.no
bearer_token_filestringFile containing a bearer token to authenticate with.no
proxy_urlstringHTTP proxy to proxy requests through.no
follow_redirectsboolWhether redirects returned by the server should be followed.trueno
enable_http2boolWhether HTTP2 is supported for requests.trueno

You can provide one of the following arguments for authentication:

Blocks

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

HierarchyBlockDescriptionRequired
basic_authbasic_authConfigure basic_auth for authenticating to the endpoint.no
authorizationauthorizationConfigure generic authorization to the endpoint.no
oauth2oauth2Configure OAuth2 for authenticating to the endpoint.no
oauth2 > tls_configtls_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.

basic_auth block

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

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

authorization block

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

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

oauth2 block

NameTypeDescriptionDefaultRequired
client_idstringOAuth2 client ID.no
client_secretsecretOAuth2 client secret.no
client_secret_filestringFile containing the OAuth2 client secret.no
scopeslist(string)List of scopes to authenticate with.no
token_urlstringURL to fetch the token from.no
endpoint_paramsmap(string)Optional parameters to append to the token URL.no
proxy_urlstringOptional proxy URL for OAuth2 requests.no

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

The oauth2 block may also contain its own separate tls_config sub-block.

tls_config block

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
key_pemsecretKey PEM-encoded text for client authentication.no
key_filestringKey file for client authentication.no
server_namestringServerName extension to indicate the name of the server.no
insecure_skip_verifyboolDisables validation of the server certificate.no
min_versionstringMinimum acceptable TLS version.no

The following pairs of arguments are mutually exclusive and cannot 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 is not 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 nomad server.

Each target includes the following labels:

  • __meta_nomad_address: the service address of the target.
  • __meta_nomad_dc: the datacenter name for the target.
  • __meta_nomad_namespace: the namespace of the target.
  • __meta_nomad_node_id: the node name defined for the target.
  • __meta_nomad_service: the name of the service the target belongs to.
  • __meta_nomad_service_address: the service address of the target.
  • __meta_nomad_service_id: the service ID of the target.
  • __meta_nomad_service_port: the service port of the target.
  • __meta_nomad_tags: the list of tags of the target joined by the tag separator.

Component health

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

Debug information

discovery.nomad does not expose any component-specific debug information.

Debug metrics

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

Example

This example discovers targets from Consul for the specified list of services:

river 
discovery.nomad "example" {
  server = "localhost:8500"
}

prometheus.scrape "demo" {
  targets    = discovery.nomad.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.