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Reference

Components

prometheus

prometheus.operator.servicemonitors

Open source

prometheus.operator.servicemonitors

prometheus.operator.servicemonitors discovers ServiceMonitor resources in your kubernetes cluster and scrapes the targets they reference. This component performs three main functions:

Discover ServiceMonitor resources from your Kubernetes cluster.
Discover Services and Endpoints in your cluster that match those ServiceMonitors.
Scrape metrics from those Endpoints, and forward them to a receiver.

The default configuration assumes Alloy is running inside a Kubernetes cluster, and uses the in-cluster configuration to access the Kubernetes API. It can be run from outside the cluster by supplying connection info in the client block, but network level access to discovered endpoints is required to scrape metrics from them.

ServiceMonitors may reference secrets for authenticating to targets to scrape them. In these cases, the secrets are loaded and refreshed only when the ServiceMonitor is updated or when this component refreshes its’ internal state, which happens on a 5-minute refresh cycle.

Usage

prometheus.operator.servicemonitors "LABEL" {
    forward_to = RECEIVER_LIST
}

Arguments

The following arguments are supported:

Name	Type	Description	Default	Required
`forward_to`	`list(MetricsReceiver)`	List of receivers to send scraped metrics to.		yes
`namespaces`	`list(string)`	List of namespaces to search for ServiceMonitor resources. If not specified, all namespaces will be searched.		no

Blocks

The following blocks are supported inside the definition of prometheus.operator.servicemonitors:

Hierarchy	Block	Description	Required
client	client	Configures Kubernetes client used to find ServiceMonitors.	no
client > basic_auth	basic_auth	Configure basic authentication to the Kubernetes API.	no
client > authorization	authorization	Configure generic authorization to the Kubernetes API.	no
client > oauth2	oauth2	Configure OAuth2 for authenticating to the Kubernetes API.	no
client > oauth2 > tls_config	tls_config	Configure TLS settings for connecting to the Kubernetes API.	no
client > tls_config	tls_config	Configure TLS settings for connecting to the Kubernetes API.	no
rule	rule	Relabeling rules to apply to discovered targets.	no
scrape	scrape	Default scrape configuration to apply to discovered targets.	no
selector	selector	Label selector for which ServiceMonitors to discover.	no
selector > match_expression	match_expression	Label selector expression for which ServiceMonitors to discover.	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 discover ServiceMonitors. 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)

rule block

The rule block contains the definition of any relabeling rules that can be applied to an input metric. If more than one rule block is defined, the transformations are applied in top-down order.

The following arguments can be used to configure a rule. All arguments are optional. Omitted fields take their default values.

Name	Type	Description	Default	Required
`action`	`string`	The relabeling action to perform.	replace	no
`modulus`	`uint`	A positive integer used to calculate the modulus of the hashed source label values.		no
`regex`	`string`	A valid RE2 expression with support for parenthesized capture groups. Used to match the extracted value from the combination of the `source_label` and `separator` fields or filter labels during the `labelkeep/labeldrop/labelmap` actions.	`(.*)`	no
`replacement`	`string`	The value against which a regular expression replace is performed, if the regular expression matches the extracted value. Supports previously captured groups.	`"$1"`	no
`separator`	`string`	The separator used to concatenate the values present in `source_labels`.	;	no
`source_labels`	`list(string)`	The list of labels whose values are to be selected. Their content is concatenated using the `separator` and matched against `regex`.		no
`target_label`	`string`	Label to which the resulting value will be written to.		no

You can use the following actions:

drop - Drops metrics where regex matches the string extracted using the source_labels and separator.
dropequal - Drop targets for which the concatenated source_labels do match target_label.
hashmod - Hashes the concatenated labels, calculates its modulo modulus and writes the result to the target_label.
keep - Keeps metrics where regex matches the string extracted using the source_labels and separator.
keepequal - Drop targets for which the concatenated source_labels do not match target_label.
labeldrop - Matches regex against all label names. Any labels that match are removed from the metric’s label set.
labelkeep - Matches regex against all label names. Any labels that don’t match are removed from the metric’s label set.
labelmap - Matches regex against all label names. Any labels that match are renamed according to the contents of the replacement field.
lowercase - Sets target_label to the lowercase form of the concatenated source_labels.
replace - Matches regex to the concatenated labels. If there’s a match, it replaces the content of the target_label using the contents of the replacement field.
uppercase - Sets target_label to the uppercase form of the concatenated source_labels.

Note
The regular expression capture groups can be referred to using either the $CAPTURE_GROUP_NUMBER or ${CAPTURE_GROUP_NUMBER} notation.

scrape block

Name	Type	Description	Default	Required
`default_scrape_interval`	`duration`	The default interval between scraping targets. Used as the default if the target resource doesn’t provide a scrape interval.	`1m`	no
`default_scrape_timeout`	`duration`	The default timeout for scrape requests. Used as the default if the target resource doesn’t provide a scrape timeout.	`10s`	no

selector block

The selector block describes a Kubernetes label selector for ServiceMonitors.

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 ServiceMonitor resources will be matched.

match_expression block

The match_expression block describes a Kubernetes label matcher expression for ServiceMonitors 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"

If there are multiple match_expressions blocks inside of a selector block, they are combined together with AND clauses.

clustering block

Name	Type	Description	Default	Required
`enabled`	`bool`	Enables sharing targets with other cluster nodes.	`false`	yes

When Alloy is using using clustering, and enabled is set to true, then this component instance opts-in to participating in the cluster to distribute scrape load between all cluster nodes.

Clustering assumes that all cluster nodes are running with the same configuration file, and that all prometheus.operator.servicemonitors components that have opted-in to using clustering, over the course of a scrape interval have the same configuration.

All prometheus.operator.servicemonitors components instances opting in to clustering use target labels and a consistent hashing algorithm to determine ownership for each of the targets between the cluster peers. Then, each peer only scrapes the subset of targets that it is responsible for, so that the scrape load is distributed. When a node joins or leaves the cluster, every peer recalculates ownership and continues scraping with the new target set. This performs better than hashmod sharding where all nodes have to be re-distributed, as only 1/N of the target’s ownership is transferred, but is eventually consistent (rather than fully consistent like hashmod sharding is).

If Alloy is not running in clustered mode, then the block is a no-op, and prometheus.operator.servicemonitors scrapes every target it receives in its arguments.

Exported fields

prometheus.operator.servicemonitors does not export any fields. It forwards all metrics it scrapes to the receiver configures with the forward_to argument.

Component health

prometheus.operator.servicemonitors is reported as unhealthy when given an invalid configuration, Prometheus components fail to initialize, or the connection to the Kubernetes API could not be established properly.

Debug information

prometheus.operator.servicemonitors reports the status of the last scrape for each configured scrape job on the component’s debug endpoint, including discovered labels, and the last scrape time.

It also exposes some debug information for each ServiceMonitor it has discovered, including any errors found while reconciling the scrape configuration from the ServiceMonitor.

Debug metrics

prometheus.operator.servicemonitors does not expose any component-specific debug metrics.

Example

This example discovers all ServiceMonitors in your cluster, and forwards collected metrics to a prometheus.remote_write component.

prometheus.remote_write "staging" {
  // Send metrics to a locally running Mimir.
  endpoint {
    url = "http://mimir:9009/api/v1/push"

    basic_auth {
      username = "example-user"
      password = "example-password"
    }
  }
}

prometheus.operator.servicemonitors "services" {
    forward_to = [prometheus.remote_write.staging.receiver]
}

This example will limit discovered ServiceMonitors to ones with the label team=ops in a specific namespace: my-app.

prometheus.operator.servicemonitors "services" {
    forward_to = [prometheus.remote_write.staging.receiver]
    namespaces = ["my-app"]
    selector {
        match_expression {
            key = "team"
            operator = "In"
            values = ["ops"]
        }
    }
}

This example will apply additional relabel rules to discovered targets to filter by hostname. This may be useful if running Alloy as a DaemonSet.

prometheus.operator.servicemonitors "services" {
    forward_to = [prometheus.remote_write.staging.receiver]
    rule {
      action = "keep"
      regex = sys.env("HOSTNAME")
      source_labels = ["__meta_kubernetes_pod_node_name"]
    }
}

Compatible components

prometheus.operator.servicemonitors can accept arguments from the following components:

Components that export Prometheus MetricsReceiver

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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prometheus.operator.servicemonitors

Usage

Arguments

Blocks

client block

basic_auth block

authorization block

oauth2 block

tls_config block

rule block

scrape block

selector block

match_expression block

clustering block

Exported fields

Component health

Debug information

Debug metrics

Example

Compatible components

Was this page helpful?

Related documentation

prometheus.operator.servicemonitors

Usage

Arguments

Blocks

client block

basic_auth block

authorization block

oauth2 block

tls_config block

rule block

scrape block

selector block

match_expression block

clustering block

Exported fields

Component health

Debug information

Debug metrics

Example

Compatible components

Was this page helpful?

Related documentation

Related resources from Grafana Labs