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Reference

Components

loki

loki.source.podlogs

Open source

loki.source.podlogs

loki.source.podlogs discovers PodLogs resources on Kubernetes. The PodLogs resources provide rules for which Kubernetes Pods to discover on your cluster.

loki.source.podlogs uses the Kubernetes API to tail the logs from the discovered Kubernetes Pods.

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

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:

Name	Type	Description	Default	Required
`forward_to`	`list(LogsReceiver)`	List of receivers to send log entries to.		yes

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 Agent Operator, which are version v1alpha1.

Field	Type	Description
`apiVersion`	string	`monitoring.grafana.com/v1alpha2`
`kind`	string	`PodLogs`
`metadata`	ObjectMeta	Metadata for the PodLogs.
`spec`	PodLogsSpec	Definition of what Pods to collect logs from.

PodLogsSpec

PodLogsSpec describes a set of Pods to collect logs from.

Field	Type	Description
`selector`	LabelSelector	Label selector of Pods to collect logs from.
`namespaceSelector`	LabelSelector	Label selector of Namespaces that Pods can be discovered in.
`relabelings`	RelabelConfig	Relabel rules to apply to discovered Pods.

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:

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
selector	selector	Label selector for which `PodLogs` to discover.	no
selector > match_expression	match_expression	Label selector expression for which `PodLogs` to discover.	no
namespace_selector	selector	Label selector for which namespaces to discover `PodLogs` in.	no
namespace_selector > match_expression	match_expression	Label selector expression for which namespaces to discover `PodLogs` in.	no
clustering	clustering	Configure the component for when Alloy is running in clustered mode.	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 Alloy 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_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
`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

At most, one of the following can be provided:

bearer_token argument.
bearer_token_file argument.
basic_auth block.
authorization block.
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.

basic_auth block

Name	Type	Description	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.

authorization block

Name	Type	Description	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.

oauth2 block

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
`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
`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.

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_connect_header should only be configured if proxy_url or proxy_from_environment are configured.

tls_config block

Name	Type	Description	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 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)

selector block

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

The following arguments are supported:

Name	Type	Description	Default	Required
`match_labels`	`map(string)`	Label keys and values used to discover resources.	`{}`	no

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:

Name	Type	Description	Required
`key`	`string`	The label name to match against.	yes
`operator`	`string`	The operator to use when matching.	yes
`values`	`list(string)`	The values used when matching.	no

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.

clustering block

Name	Type	Description	Default	Required
`enabled`	`bool`	Distribute log collection with other cluster nodes.		yes

When Alloy is using clustering, and enabled is set to true, then this loki.source.podlogs component instance opts-in to participating in the cluster to distribute the load of log collection between all cluster nodes.

If Alloy is not running in clustered mode, then the block is a no-op and loki.source.podlogs collects logs based on every PodLogs resource discovered.

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 written to Loki.

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

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

Compatible components

loki.source.podlogs can accept arguments from the following components:

Components that export Loki LogsReceiver

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.

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