Documentation Grafana Alloy Reference Components discovery discovery.kubelet

discovery.kubelet

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

Usage

Alloy Copy

discovery.kubelet "LABEL" {
}

Requirements

• The Kubelet must be reachable from the alloy Pod network.
• Follow the Kubelet authorization documentation to configure authentication to the Kubelet API.

Arguments

You can use the following arguments with discovery.kubelet:

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

discovery.kubelet appends a /pods path to url to request the available Pods. You can have additional paths in the url. For example, if url is https://kubernetes.default.svc.cluster.local:443/api/v1/nodes/cluster-node-1/proxy, then discovery.kubelet sends a request on https://kubernetes.default.svc.cluster.local:443/api/v1/nodes/cluster-node-1/proxy/pods

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.kubelet:

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.

oauth2

The oauth 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:

• __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.

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 doesn’t expose any component-specific debug information.

Debug metrics

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

Examples

Bearer token file authentication

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

Alloy 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:

Alloy 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