loki.source.kubernetes.md

---

title: loki.source.kubernetes
labels:
  stage: experimental

---

loki.source.kubernetes

{{< docs/shared lookup="flow/stability/experimental.md" source="agent" >}}

loki.source.kubernetes tails logs from Kubernetes containers using the Kubernetes API. It has the following benefits over loki.source.file:

• It works without a privileged container.

• It works without a root user.

• It works without needing access to the filesystem of the Kubernetes node.

• It doesn't require a DaemonSet to collect logs, so one agent could collect logs for the whole cluster.

NOTE: Because loki.source.kubernetes uses the Kubernetes API to tail logs, it uses more network traffic and CPU consumption of Kubelets than loki.source.file.

Multiple loki.source.kubernetes components can be specified by giving them different labels.

Usage

loki.source.kubernetes "LABEL" {
  targets    = TARGET_LIST
  forward_to = RECEIVER_LIST
}

Arguments

The component starts a new reader for each of the given targets and fans out log entries to the list of receivers passed in forward_to.

loki.source.kubernetes supports the following arguments:

Name	Type	Description	Default	Required
targets	list(map(string))	List of files to read from.		yes
forward_to	list(LogsReceiver)	List of receivers to send log entries to.		yes

Each target in targets must have the following labels:

• __meta_kubernetes_namespace or __pod_namespace__ to specify the namespace of the pod to tail.

• __meta_kubernetes_pod_name or __pod_name__ to specify the name of the pod to tail.

• __meta_kubernetes_pod_container_name or __pod_container_name__ to specify the container within the pod to tail.

• __meta_kubernetes_pod_uid or __pod_uid__ to specify the UID of the pod to tail.

By default, all of these labels are present when the output discovery.kubernetes is used.

A log tailer is started for each unique target in targets. Log tailers will reconnect with exponential backoff to Kubernetes if the log stream returns before the container has permanently terminated.

Blocks

The following blocks are supported inside the definition of loki.source.kubernetes:

Hierarchy	Block	Description	Required
client	client	Configures Kubernetes client used to tail logs.	no
client > basic_auth	basic_auth	Configure basic_auth for authenticating to the endpoint.	no
client > authorization	authorization	Configure generic authorization to the endpoint.	no
client > oauth2	oauth2	Configure OAuth2 for authenticating to the endpoint.	no
client > oauth2 > tls_config	tls_config	Configure TLS settings for connecting to the endpoint.	no
client > tls_config	tls_config	Configure TLS settings for connecting to the endpoint.	no

The > symbol indicates deeper levels of nesting. For example, client > basic_auth refers to a basic_auth block defined inside a client block.

client block

The client block configures the Kubernetes client used to tail logs from containers. If the client block isn't provided, the default in-cluster configuration with the service account of the running Grafana Agent pod is used.

The following arguments are supported:

Name	Type	Description	Default	Required
api_server	string	URL of the Kubernetes API server.		no
kubeconfig_file	string	Path of the kubeconfig file to use for connecting to Kubernetes.		no
bearer_token	secret	Bearer token to authenticate with.		no
bearer_token_file	string	File containing a bearer token to authenticate with.		no
proxy_url	string	HTTP proxy to proxy requests through.		no
follow_redirects	bool	Whether redirects returned by the server should be followed.	true	no
enable_http2	bool	Whether HTTP2 is supported for requests.	true	no

At most one of the following can be provided:

• bearer_token argument.

• bearer_token_file argument.

• basic_auth block.

• authorization block.

• oauth2 block.

basic_auth block

{{< docs/shared lookup="flow/reference/components/basic-auth-block.md" source="agent" >}}

authorization block

{{< docs/shared lookup="flow/reference/components/authorization-block.md" source="agent" >}}

oauth2 block

{{< docs/shared lookup="flow/reference/components/oauth2-block.md" source="agent" >}}

tls_config block

{{< docs/shared lookup="flow/reference/components/tls-config-block.md" source="agent" >}}

Exported fields

loki.source.kubernetes does not export any fields.

Component health

loki.source.kubernetes is only reported as unhealthy if given an invalid configuration.

Debug information

loki.source.kubernetes exposes some target-level debug information per target:

• The labels associated with the target.

• The full set of labels which were found during service discovery.

• The most recent time a log line was read and forwarded to the next components in the pipeline.

• The most recent error from tailing, if any.

Debug metrics

loki.source.kubernetes does not expose any component-specific debug metrics.

Example

This example collects logs from all Kubernetes pods and forwards them to a loki.write component so they are written to Loki.

discovery.kubernetes "pods" {
  role = "pod"
}

loki.source.kubernetes "pods" {
  targets    = discovery.kubernetes.pods.targets
  forward_to = [loki.write.local.receiver]
}

loki.write "local" {
  endpoint {
    url = env("LOKI_URL")
  }
}