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Experimental

loki.rules.kubernetes

EXPERIMENTAL: This is an experimental component. Experimental components are subject to frequent breaking changes, and may be removed with no equivalent replacement.

loki.rules.kubernetes discovers PrometheusRule Kubernetes resources and loads them into a Loki instance.

  • You can specify multiple loki.rules.kubernetes components by giving them different labels.
  • Kubernetes label selectors can be used to limit the Namespace and PrometheusRule resources considered during reconciliation.
  • Compatible with the Ruler APIs of Grafana Loki, Grafana Cloud, and Grafana Enterprise Metrics.
  • Compatible with the PrometheusRule CRD from the prometheus-operator.
  • This component accesses the Kubernetes REST API from within a Pod.

Note

This component requires [Role-based access control (RBAC)][] to be set up in Kubernetes for Grafana Agent to access it via the Kubernetes REST API.

Role-based access control (RBAC)]: https://kubernetes.io/docs/reference/access-authn-authz/rbac/

Usage

river
loki.rules.kubernetes "LABEL" {
  address = LOKI_RULER_URL
}

Arguments

loki.rules.kubernetes supports the following arguments:

NameTypeDescriptionDefaultRequired
addressstringURL of the Loki ruler.yes
tenant_idstringLoki tenant ID.no
use_legacy_routesboolWhether to use deprecated ruler API endpoints.falseno
sync_intervaldurationAmount of time between reconciliations with Loki.“30s”no
loki_namespace_prefixstringPrefix used to differentiate multiple Grafana Agent deployments.“agent”no
bearer_tokensecretBearer token to authenticate with.no
bearer_token_filestringFile containing a bearer token to authenticate with.no
proxy_urlstringHTTP proxy to proxy requests through.no
follow_redirectsboolWhether redirects returned by the server should be followed.trueno
enable_http2boolWhether HTTP2 is supported for requests.trueno

At most, one of the following can be provided:

If no tenant_id is provided, the component assumes that the Loki instance at address is running in single-tenant mode and no X-Scope-OrgID header is sent.

The sync_interval argument determines how often Loki’s ruler API is accessed to reload the current state. Interaction with the Kubernetes API works differently. Updates are processed as events from the Kubernetes API server according to the informer pattern.

You can use the loki_namespace_prefix argument to separate the rules managed by multiple Grafana Agent deployments across your infrastructure. You should set the prefix to a unique value for each deployment.

Blocks

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

HierarchyBlockDescriptionRequired
rule_namespace_selectorlabel_selectorLabel selector for Namespace resources.no
rule_namespace_selector > match_expressionmatch_expressionLabel match expression for Namespace resources.no
rule_selectorlabel_selectorLabel selector for PrometheusRule resources.no
rule_selector > match_expressionmatch_expressionLabel match expression for PrometheusRule resources.no
basic_authbasic_authConfigure basic_auth for authenticating to the endpoint.no
authorizationauthorizationConfigure generic authorization to the endpoint.no
oauth2oauth2Configure OAuth2 for authenticating to the endpoint.no
oauth2 > tls_configtls_configConfigure TLS settings for connecting to the endpoint.no
tls_configtls_configConfigure TLS settings for connecting to the endpoint.no

The > symbol indicates deeper levels of nesting. For example, oauth2 > tls_config refers to a tls_config block defined inside an oauth2 block.

label_selector block

The label_selector block describes a Kubernetes label selector for rule or namespace discovery.

The following arguments are supported:

NameTypeDescriptionDefaultRequired
match_labelsmap(string)Label keys and values used to discover resources.{}yes

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 rule or namespace discovery.

The following arguments are supported:

NameTypeDescriptionDefaultRequired
keystringThe label name to match against.yes
operatorstringThe operator to use when matching.yes
valueslist(string)The values used when matching.no

The operator argument should be one of the following strings:

  • "in"
  • "notin"
  • "exists"

basic_auth block

NameTypeDescriptionDefaultRequired
password_filestringFile containing the basic auth password.no
passwordsecretBasic auth password.no
usernamestringBasic auth username.no

password and password_file are mutually exclusive, and only one can be provided inside a basic_auth block.

authorization block

NameTypeDescriptionDefaultRequired
credentials_filestringFile containing the secret value.no
credentialssecretSecret value.no
typestringAuthorization type, for example, “Bearer”.no

credential and credentials_file are mutually exclusive, and only one can be provided inside an authorization block.

oauth2 block

NameTypeDescriptionDefaultRequired
client_idstringOAuth2 client ID.no
client_secret_filestringFile containing the OAuth2 client secret.no
client_secretsecretOAuth2 client secret.no
endpoint_paramsmap(string)Optional parameters to append to the token URL.no
proxy_urlstringHTTP proxy to send requests through.no
no_proxystringComma-separated list of IP addresses, CIDR notations, and domain names to exclude from proxying.no
proxy_from_environmentboolUse the proxy URL indicated by environment variables.falseno
proxy_connect_headermap(list(secret))Specifies headers to send to proxies during CONNECT requests.no
scopeslist(string)List of scopes to authenticate with.no
token_urlstringURL 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

NameTypeDescriptionDefaultRequired
ca_pemstringCA PEM-encoded text to validate the server with.no
ca_filestringCA certificate to validate the server with.no
cert_pemstringCertificate PEM-encoded text for client authentication.no
cert_filestringCertificate file for client authentication.no
insecure_skip_verifyboolDisables validation of the server certificate.no
key_filestringKey file for client authentication.no
key_pemsecretKey PEM-encoded text for client authentication.no
min_versionstringMinimum acceptable TLS version.no
server_namestringServerName 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)

Exported fields

loki.rules.kubernetes does not export any fields.

Component health

loki.rules.kubernetes is reported as unhealthy if given an invalid configuration or an error occurs during reconciliation.

Debug information

loki.rules.kubernetes exposes resource-level debug information.

The following are exposed per discovered PrometheusRule resource:

  • The Kubernetes namespace.
  • The resource name.
  • The resource uid.
  • The number of rule groups.

The following are exposed per discovered Loki rule namespace resource:

  • The namespace name.
  • The number of rule groups.

Only resources managed by the component are exposed - regardless of how many actually exist.

Debug metrics

Metric NameTypeDescription
loki_rules_config_updates_totalcounterNumber of times the configuration has been updated.
loki_rules_events_totalcounterNumber of events processed, partitioned by event type.
loki_rules_events_failed_totalcounterNumber of events that failed to be processed, partitioned by event type.
loki_rules_events_retried_totalcounterNumber of events that were retried, partitioned by event type.
loki_rules_client_request_duration_secondshistogramDuration of requests to the Loki API.

Example

This example creates a loki.rules.kubernetes component that loads discovered rules to a local Loki instance under the team-a tenant. Only namespaces and rules with the agent label set to yes are included.

river
loki.rules.kubernetes "local" {
    address = "loki:3100"
    tenant_id = "team-a"

    rule_namespace_selector {
        match_labels = {
            agent = "yes",
        }
    }

    rule_selector {
        match_labels = {
            agent = "yes",
        }
    }
}

This example creates a loki.rules.kubernetes component that loads discovered rules to Grafana Cloud.

river
loki.rules.kubernetes "default" {
    address = "GRAFANA_CLOUD_URL"
    basic_auth {
        username = "GRAFANA_CLOUD_USER"
        password = "GRAFANA_CLOUD_API_KEY"
        // Alternatively, load the password from a file:
        // password_file = "GRAFANA_CLOUD_API_KEY_PATH"
    }
}

The following example is an RBAC configuration for Kubernetes. It authorizes Grafana Agent to query the Kubernetes REST API:

yaml
apiVersion: v1
kind: ServiceAccount
metadata:
  name: grafana-agent
  namespace: default
---
apiVersion: rbac.authorization.k8s.io/v1
kind: ClusterRole
metadata:
  name: grafana-agent
rules:
- apiGroups: [""]
  resources: ["namespaces"]
  verbs: ["get", "list", "watch"]
- apiGroups: ["monitoring.coreos.com"]
  resources: ["prometheusrules"]
  verbs: ["get", "list", "watch"]
---
apiVersion: rbac.authorization.k8s.io/v1
kind: ClusterRoleBinding
metadata:
  name: grafana-agent
subjects:
- kind: ServiceAccount
  name: grafana-agent
  namespace: default
roleRef:
  kind: ClusterRole
  name: grafana-agent
  apiGroup: rbac.authorization.k8s.io