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Documentation Grafana Agent Grafana Agent Flow Reference Components loki.source.podlogs

loki.source.podlogs

loki.source.podlogs discovers PodLogs resources on Kubernetes and, using the Kubernetes API, tails logs from Kubernetes containers of Pods specified by the discovered them.

loki.source.podlogs is similar to loki.source.kubernetes, but uses custom resources rather than being fed targets from another Flow component.

NOTE: Unlike loki.source.kubernetes, it is not possible to distribute responsibility of collecting logs across multiple agents. To avoid collecting duplicate logs, only one agent should be running a loki.source.podlogs component.

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

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

Usage

Alloy Copy

loki.source.podlogs "LABEL" {
  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.podlogs supports the following arguments:

loki.source.podlogs searches for PodLogs resources on Kubernetes. Each PodLogs resource describes a set of pods to tail logs from.

PodLogs custom resource

The PodLogs resource describes a set of Pods to collect logs from.

NOTE: loki.source.podlogs looks for PodLogs of monitoring.grafana.com/v1alpha2, and is not compatible with PodLogs from the Grafana Agent Operator, which are version v1alpha1.

PodLogsSpec

PodLogsSpec describes a set of Pods to collect logs from.

If selector is left as the default value, all Pods are discovered. If namespaceSelector is left as the default value, all Namespaces are used for Pod discovery.

The relabelings field can be used to modify labels from discovered Pods. The following meta labels are available for relabeling:

• __meta_kubernetes_namespace: The namespace of the Pod.
• __meta_kubernetes_pod_name: The name of the Pod.
• __meta_kubernetes_pod_ip: The pod IP of the Pod.
• __meta_kubernetes_pod_label_<labelname>: Each label from the Pod.
• __meta_kubernetes_pod_labelpresent_<labelname>: true for each label from the Pod.
• __meta_kubernetes_pod_annotation_<annotationname>: Each annotation from the Pod.
• __meta_kubernetes_pod_annotationpresent_<annotationname>: true for each annotation from the Pod.
• __meta_kubernetes_pod_container_init: true if the container is an InitContainer.
• __meta_kubernetes_pod_container_name: Name of the container.
• __meta_kubernetes_pod_container_image: The image the container is using.
• __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.
• __meta_kubernetes_pod_controller_kind: Object kind of the Pod’s controller.
• __meta_kubernetes_pod_controller_name: Name of the Pod’s controller.

In addition to the meta labels, the following labels are exposed to tell loki.source.podlogs which container to tail:

• __pod_namespace__: The namespace of the Pod.
• __pod_name__: The name of the Pod.
• __pod_container_name__: The container name within the Pod.
• __pod_uid__: The UID of the Pod.

Blocks

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

The > symbol indicates deeper levels of nesting. For example, client > http_client_config refers to an http_client_config 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:

http_client_config block

The http_client_config block configures settings used to connect to the Kubernetes API server.

selector block

The selector block describes a Kubernetes label selector for PodLogs or Namespace discovery.

The following arguments are supported:

When the match_labels argument is empty, all resources will be matched.

match_expression block

The match_expression block describes a Kubernetes label match expression for PodLogs or Namespace discovery.

The following arguments are supported:

The operator argument must be one of the following strings:

• "In"
• "NotIn"
• "Exists"
• "DoesNotExist"

Both selector and namespace_selector can make use of multiple match_expression inner blocks which are treated as AND clauses.

Exported fields

loki.source.podlogs does not export any fields.

Component health

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

Debug information

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

Example

This example discovers all PodLogs resources and forwards collected logs to a loki.write component so they are can be written to Loki.

Alloy Copy

loki.source.podlogs "default" {
  forward_to = [loki.write.local.receiver]
}

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