--- title: "discovery.kubelet | Grafana Alloy documentation" description: "Learn about discovery.kubelet" --- # `discovery.kubelet` `discovery.kubelet` discovers Kubernetes Pods running on the specified Kubelet and exposes them as scrape targets. ## Usage Alloy ![Copy code to clipboard](/media/images/icons/icon-copy-small-2.svg) Copy ```alloy discovery.kubelet "LABEL" { } ``` ## Requirements - The Kubelet must be reachable from the `alloy` Pod network. - Follow the [Kubelet authorization](https://kubernetes.io/docs/reference/access-authn-authz/kubelet-authn-authz/#kubelet-authorization) documentation to configure authentication to the Kubelet API. ## Arguments You can use the following arguments with `discovery.kubelet`: Expand table | Name | Type | Description | Default | Required | |--------------------------|---------------------|--------------------------------------------------------------------------------------------------|-----------------------------|----------| | `url` | `string` | URL of the Kubelet server. | `"https://localhost:10250"` | no | | `refresh_interval` | `duration` | How often the Kubelet should be polled for scrape targets. | `"5s"` | no | | `namespaces` | `list(string)` | A list of namespaces to extract target Pods from. | | no | | `bearer_token_file` | `string` | File containing a bearer token to authenticate with. | | no | | `bearer_token` | `secret` | Bearer token to authenticate with. | | no | | `enable_http2` | `bool` | Whether HTTP2 is supported for requests. | `true` | no | | `follow_redirects` | `bool` | Whether redirects returned by the server should be followed. | `true` | no | | `http_headers` | `map(list(secret))` | Custom HTTP headers to be sent along with each request. The map key is the header name. | | no | | `proxy_url` | `string` | HTTP proxy to send requests through. | | no | | `no_proxy` | `string` | Comma-separated list of IP addresses, CIDR notations, and domain names to exclude from proxying. | | no | | `proxy_from_environment` | `bool` | Use the proxy URL indicated by environment variables. | `false` | no | | `proxy_connect_header` | `map(list(secret))` | Specifies headers to send to proxies during CONNECT requests. | | no | 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`]\[authorization] block - \[`basic_auth`]\[basic\_auth] block - [`bearer_token_file`](#arguments) argument - [`bearer_token`](#arguments) argument - \[`oauth2`]\[oauth2] 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. ## Blocks You can use the following blocks with `discovery.kubelet`: No valid configuration blocks found. ### `authorization` The `authorization` block configures generic authorization to the endpoint. Expand table | Name | Type | Description | Default | Required | |--------------------|----------|--------------------------------------------|---------|----------| | `credentials_file` | `string` | File containing the secret value. | | no | | `credentials` | `secret` | Secret value. | | no | | `type` | `string` | Authorization 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. Expand table | Name | Type | Description | Default | Required | |-----------------|----------|------------------------------------------|---------|----------| | `password_file` | `string` | File containing the basic auth password. | | no | | `password` | `secret` | Basic auth password. | | no | | `username` | `string` | Basic 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. Expand table | Name | Type | Description | Default | Required | |--------------------------|---------------------|--------------------------------------------------------------------------------------------------|---------|----------| | `client_id` | `string` | OAuth2 client ID. | | no | | `client_secret_file` | `string` | File containing the OAuth2 client secret. | | no | | `client_secret` | `secret` | OAuth2 client secret. | | no | | `endpoint_params` | `map(string)` | Optional parameters to append to the token URL. | | no | | `no_proxy` | `string` | Comma-separated list of IP addresses, CIDR notations, and domain names to exclude from proxying. | | no | | `proxy_connect_header` | `map(list(secret))` | Specifies headers to send to proxies during CONNECT requests. | | no | | `proxy_from_environment` | `bool` | Use the proxy URL indicated by environment variables. | `false` | no | | `proxy_url` | `string` | HTTP proxy to send requests through. | | no | | `scopes` | `list(string)` | List of scopes to authenticate with. | | no | | `token_url` | `string` | URL 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. Expand table | Name | Type | Description | Default | Required | |------------------------|----------|----------------------------------------------------------|---------|----------| | `ca_pem` | `string` | CA PEM-encoded text to validate the server with. | | no | | `ca_file` | `string` | CA certificate to validate the server with. | | no | | `cert_pem` | `string` | Certificate PEM-encoded text for client authentication. | | no | | `cert_file` | `string` | Certificate file for client authentication. | | no | | `insecure_skip_verify` | `bool` | Disables validation of the server certificate. | | no | | `key_file` | `string` | Key file for client authentication. | | no | | `key_pem` | `secret` | Key PEM-encoded text for client authentication. | | no | | `min_version` | `string` | Minimum acceptable TLS version. | | no | | `server_name` | `string` | ServerName 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: Expand table | Name | Type | Description | |-----------|---------------------|-----------------------------------------------------| | `targets` | `list(map(string))` | The set of targets discovered from the Kubelet API. | 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_`: Each label from the Pod object. - `__meta_kubernetes_pod_labelpresent_`: `true` for each label from the Pod object. - `__meta_kubernetes_pod_annotation_`: Each annotation from the Pod object. - `__meta_kubernetes_pod_annotationpresent_`: `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 `://`. - `__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 can’t 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` 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 code to clipboard](/media/images/icons/icon-copy-small-2.svg) Copy ```alloy 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 = "" basic_auth { username = "" password = "" } } } ``` Replace the following: - *``* : The URL of the Prometheus remote\_write-compatible server to send metrics to. - *``* : The username to use for authentication to the `remote_write` API. - *``* : 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 code to clipboard](/media/images/icons/icon-copy-small-2.svg) Copy ```alloy 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 = "" basic_auth { username = "" password = ">PASSWORD>" } } } ``` Replace the following: - *``* : The URL of the Prometheus remote\_write-compatible server to send metrics to. - *``* : The username to use for authentication to the `remote_write` API. - *``* : 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](../../../compatibility/#targets-consumers) > 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.