Important: This documentation is about an older version. It's relevant only to the release noted, many of the features and functions have been updated or replaced. Please view the current version.

DocumentationGrafana AgentFlow modeReferenceComponents referencediscovery.kubelet

discovery.kubelet

discovery.kubelet discovers Kubernetes pods running on the specified Kubelet and exposes them as scrape targets.

Usage

river Copy

discovery.kubelet "LABEL" {
}

Requirements

• The Kubelet must be reachable from the grafana-agent pod network.
• Follow the Kubelet authorization documentation to configure authentication to the Kubelet API.

Arguments

The following arguments are supported:

One of the following authentication methods must be provided if kubelet authentication is enabled

• bearer_token argument.
• bearer_token_file argument.
• authorization block.

The namespaces list limits the namespaces to discover resources in. If omitted, all namespaces are searched.

Blocks

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

authorization block

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

tls_config block

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 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:

Each target includes the following labels:

• __address__: The target address to scrape derived from the pod IP and container port.
• __meta_kubernetes_namespace: The namespace of the pod object.
• __meta_kubernetes_pod_name: The name of the pod object.
• __meta_kubernetes_pod_ip: The pod IP of the pod object.
• __meta_kubernetes_pod_label_<labelname>: Each label from the pod object.
• __meta_kubernetes_pod_labelpresent_<labelname>: true for each label from the pod object.
• __meta_kubernetes_pod_annotation_<annotationname>: Each annotation from the pod object.
• __meta_kubernetes_pod_annotationpresent_<annotationname>: true for each annotation from the pod object.
• __meta_kubernetes_pod_container_init: true if the container is an InitContainer.
• __meta_kubernetes_pod_container_name: Name of the container the target address points to.
• __meta_kubernetes_pod_container_id: ID of the container the target address points to. The ID is in the form <type>://<container_id>.
• __meta_kubernetes_pod_container_image: The image the container is using.
• __meta_kubernetes_pod_container_port_name: Name of the container port.
• __meta_kubernetes_pod_container_port_number: Number of the container port.
• __meta_kubernetes_pod_container_port_protocol: Protocol of the container port.
• __meta_kubernetes_pod_ready: Set to true or false for the pod’s ready state.
• __meta_kubernetes_pod_phase: Set to Pending, Running, Succeeded, Failed or Unknown in the lifecycle.
• __meta_kubernetes_pod_node_name: The name of the node the pod is scheduled onto.
• __meta_kubernetes_pod_host_ip: The current host IP of the pod object.
• __meta_kubernetes_pod_uid: The UID of the pod object.
• __meta_kubernetes_pod_controller_kind: Object kind of the pod controller.
• __meta_kubernetes_pod_controller_name: Name of the pod controller.

Note: The Kubelet API used by this component is an internal API and therefore the data in the response returned from the API cannot be guaranteed between different versions of the Kubelet.

Component health

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

Debug information

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

Debug metrics

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

Examples

Bearer token file authentication

This example uses a bearer token file to authenticate to the Kubelet API:

river Copy

discovery.kubelet "k8s_pods" {
  bearer_token_file = "/var/run/secrets/kubernetes.io/serviceaccount/token"
}

prometheus.scrape "demo" {
  targets    = discovery.kubelet.k8s_pods.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.

Limit searched namespaces

This example limits the namespaces where pods are discovered using the namespaces argument:

river Copy

discovery.kubelet "k8s_pods" {
  bearer_token_file = "/var/run/secrets/kubernetes.io/serviceaccount/token"
  namespaces = ["default", "kube-system"]
}

prometheus.scrape "demo" {
  targets    = discovery.kubelet.k8s_pods.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.kubelet has exports that can be consumed by the following components:

• Components that consume Targets