Caution
Grafana Alloy is the new name for our distribution of the OTel collector. Grafana Agent has been deprecated and is in Long-Term Support (LTS) through October 31, 2025. Grafana Agent will reach an End-of-Life (EOL) on November 1, 2025. Read more about why we recommend migrating to Grafana Alloy.
Important: This documentation is about an older version. It's relevant only to the release noted, many of the features and functions have been updated or replaced. Please view the current version.
loki.source.kubernetes
EXPERIMENTAL: This is an experimental component. Experimental components are subject to frequent breaking changes, and may be removed with no equivalent replacement.
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 thanloki.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:
basic_auth block
Name | Type | Description | Default | Required |
---|---|---|---|---|
username | string | Basic auth username. | no | |
password | secret | Basic auth password. | no | |
password_file | string | File containing the basic auth password. | no |
password
and password_file
are mutually exclusive and only one can be
provided inside of a basic_auth
block.
authorization block
Name | Type | Description | Default | Required |
---|---|---|---|---|
type | string | Authorization type, for example, “Bearer”. | no | |
credentials | secret | Secret value. | no | |
credentials_file | string | File containing the secret value. | no |
credential
and credentials_file
are mutually exclusive and only one can be
provided inside of an authorization
block.
oauth2 block
Name | Type | Description | Default | Required |
---|---|---|---|---|
client_id | string | OAuth2 client ID. | no | |
client_secret | secret | OAuth2 client secret. | no | |
client_secret_file | string | File containing the OAuth2 client secret. | no | |
scopes | list(string) | List of scopes to authenticate with. | no | |
token_url | string | URL to fetch the token from. | no | |
endpoint_params | map(string) | Optional parameters to append to the token URL. | no | |
proxy_url | string | Optional proxy URL for OAuth2 requests. | no |
client_secret
and client_secret_file
are mutually exclusive and only one
can be provided inside of an oauth2
block.
The oauth2
block may also contain its own separate tls_config
sub-block.
tls_config block
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 | |
key_pem | secret | Key PEM-encoded text for client authentication. | no | |
key_file | string | Key file for client authentication. | no | |
server_name | string | ServerName extension to indicate the name of the server. | no | |
insecure_skip_verify | bool | Disables validation of the server certificate. | no | |
min_version | string | Minimum acceptable TLS version. | no |
The following pairs of arguments are mutually exclusive and cannot both be set simultaneously:
ca_pem
andca_file
cert_pem
andcert_file
key_pem
andkey_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)
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")
}
}