This is documentation for the next version of Alloy. For the latest stable release, go to the latest version.
loki.source.kubernetes
loki.source.kubernetes
tails logs from Kubernetes containers using the Kubernetes API.
Note
This component collects logs from Kubernetes Pods. You can’t use this component to collect logs from Kubernetes Nodes.
This component 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 Alloy could collect logs for the whole cluster.
Note
Becauseloki.source.kubernetes
uses the Kubernetes API to tail logs, it uses more network traffic and CPU consumption of Kubelets thanloki.source.file
.
You can specify multiple loki.source.kubernetes
components 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 |
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:
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 | 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.
authorization block
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.
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_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 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 | |
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
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)
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.kubernetes
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.kubernetes
collects logs from every target it receives in its arguments.
Clustering only looks at the following labels for determining the shard key:
__pod_namespace__
__pod_name__
__pod_container_name__
__pod_uid__
__meta_kubernetes_namespace
__meta_kubernetes_pod_name
__meta_kubernetes_pod_container_name
__meta_kubernetes_pod_uid
container
pod
job
namespace
Exported fields
loki.source.kubernetes
doesn’t 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 = sys.env("LOKI_URL")
}
}
Compatible components
loki.source.kubernetes
can accept arguments from the following components:
- Components that export Targets
- 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.