Open source


prometheus.remote_write collects metrics sent from other components into a Write-Ahead Log (WAL) and forwards them over the network to a series of user-supplied endpoints. Metrics are sent over the network using the Prometheus Remote Write protocol.

Multiple prometheus.remote_write components can be specified by giving them different labels.


prometheus.remote_write "LABEL" {
  endpoint {




The following arguments are supported:

external_labelsmap(string)Labels to add to metrics sent over the


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

endpointendpointLocation to send metrics
endpoint > basic_authbasic_authConfigure basic_auth for authenticating to the
endpoint > authorizationauthorizationConfigure generic authorization to the
endpoint > oauth2oauth2Configure OAuth2 for authenticating to the
endpoint > oauth2 > tls_configtls_configConfigure TLS settings for connecting to the
endpoint > tls_configtls_configConfigure TLS settings for connecting to the
endpoint > queue_configqueue_configConfiguration for how metrics are batched before
endpoint > metadata_configmetadata_configConfiguration for how metric metadata is
walwalConfiguration for the component’s

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

endpoint block

The endpoint block describes a single location to send metrics to. Multiple endpoint blocks can be provided to send metrics to multiple locations.

The following arguments are supported:

urlstringFull URL to send metrics to.yes
namestringOptional name to identify the endpoint in
remote_timeoutdurationTimeout for requests made to the URL."30s"no
headersmap(string)Extra headers to deliver with the
send_exemplarsboolWhether exemplars should be sent.trueno
send_native_histogramsboolWhether native histograms should be sent.falseno
bearer_tokensecretBearer token to authenticate
bearer_token_filestringFile containing a bearer token to authenticate
proxy_urlstringHTTP proxy to proxy requests
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:

When multiple endpoint blocks are provided, metrics are concurrently sent to all configured locations. Each endpoint has a queue which is used to read metrics from the WAL and queue them for sending. The queue_config block can be used to customize the behavior of the queue.

Endpoints can be named for easier identification in debug metrics using the name argument. If the name argument isn’t provided, a name is generated based on a hash of the endpoint settings.

When send_native_histograms is true, native Prometheus histogram samples sent to prometheus.remote_write are forwarded to the configured endpoint. If the endpoint doesn’t support receiving native histogram samples, pushing metrics fails.

basic_auth block

usernamestringBasic auth
passwordsecretBasic auth
password_filestringFile containing the basic auth

password and password_file are mututally exclusive and only one can be provided inside of a basic_auth block.

authorization block

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

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

oauth2 block

client_idstringOAuth2 client
client_secretsecretOAuth2 client
client_secret_filestringFile containing the OAuth2 client
scopeslist(string)List of scopes to authenticate
token_urlstringURL to fetch the token
endpoint_paramsmap(string)Optional parameters to append to the token
proxy_urlstringOptional proxy URL for OAuth2

client_secret and client_secret_file are mututally 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

ca_filestringCA certificate to validate the server
cert_filestringCertificate file for client
key_filestringKey file for client
server_namestringServerName extension to indicate the name of the
insecure_skip_verifyboolDisables validation of the server
min_versionstringMinimum acceptable TLS

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)

queue_config block

capacitynumberNumber of samples to buffer per shard.2500no
min_shardsnumberMinimum amount of concurrent shards sending samples to the endpoint.1no
max_shardsnumberMaximum number of concurrent shards sending samples to the endpoint.200no
max_samples_per_sendnumberMaximum number of samples per send.500no
batch_send_deadlinedurationMaximum time samples will wait in the buffer before sending."5s"no
min_backoffdurationInitial retry delay. The backoff time gets doubled for each retry."30ms"no
max_backoffdurationMaximum retry delay."5s"no
retry_on_http_429boolRetry when an HTTP 429 status code is received.falseno

Each queue then manages a number of concurrent shards which is responsible for sending a fraction of data to their respective endpoints. The number of shards is automatically raised if samples are not being sent to the endpoint quickly enough. The range of permitted shards can be configured with the min_shards and max_shards arguments.

Each shard has a buffer of samples it will keep in memory, controlled with the capacity argument. New metrics aren’t read from the WAL unless there is at least one shard that is not at maximum capcity.

The buffer of a shard is flushed and sent to the endpoint either after the shard reaches the number of samples specified by max_samples_per_send or the duration specified by batch_send_deadline has elapsed since the last flush for that shard.

Shards retry requests which fail due to a recoverable error. An error is recoverable if the server responds with an HTTP 5xx status code. The delay between retries can be customized with the min_backoff and max_backoff arguments.

The retry_on_http_429 argument specifies whether HTTP 429 status code responses should be treated as recoverable errors; other HTTP 4xx status code responses are never considered recoverable errors. When retry_on_http_429 is enabled, Retry-After response headers from the servers are honored.

metadata_config block

sendboolControls whether metric metadata is sent to the endpoint.trueno
send_intervaldurationHow frequently metric metadata is sent to the endpoint."1m"no
max_samples_per_sendnumberMaximum number of metadata samples to send to the endpoint at once.500no

wal block

The wal block customizes the Write-Ahead Log (WAL) used to temporarily store metrics before they are sent to the configured set of endpoints.

truncate_frequencydurationHow frequently to clean up the WAL."2h"no
min_keepalive_timedurationMinimum time to keep data in the WAL before it can be removed."5m"no
max_keepalive_timedurationMaximum time to keep data in the WAL before removing it."8h"no

The WAL serves two primary purposes:

  • Buffer unsent metrics in case of intermittent network issues.
  • Populate in-memory cache after a process restart.

The WAL is located inside a component-specific directory relative to the storage path Grafana Agent is configured to use. See the agent run documentation for how to change the storage path.

The truncate_frequency argument configures how often to clean up the WAL. Every time the truncate_frequency period elapses, the lower two-thirds of data is removed from the WAL and is no available for sending.

When a WAL clean-up starts, the lowest successfully sent timestamp is used to determine how much data is safe to remove from the WAL. The min_keepalive_time and max_keepalive_time control the permitted age range of data in the WAL; samples aren’t removed until they are at least as old as min_keepalive_time, and samples are forcibly removed if they are older than max_keepalive_time.

Exported fields

The following fields are exported and can be referenced by other components:

receiverreceiverA value which other components can use to send metrics to.

Component health

prometheus.remote_write is only reported as unhealthy if given an invalid configuration. In those cases, exported fields are kept at their last healthy values.

Debug information

prometheus.remote_write does not expose any component-specific debug information.

Debug metrics

  • agent_wal_storage_active_series (gauge): Current number of active series being tracked by the WAL.
  • agent_wal_storage_deleted_series (gauge): Current number of series marked for deletion from memory.
  • agent_wal_storage_created_series_total (counter): Total number of created series appended to the WAL.
  • agent_wal_storage_removed_series_total (counter): Total number of series removed from the WAL.
  • agent_wal_samples_appended_total (counter): Total number of samples appended to the WAL.
  • agent_wal_exemplars_appended_total (counter): Total number of exemplars appended to the WAL.
  • prometheus_remote_storage_samples_total (counter): Total number of samples sent to remote storage.
  • prometheus_remote_storage_exemplars_total (counter): Total number of exemplars sent to remote storage.
  • prometheus_remote_storage_metadata_total (counter): Total number of metadata entries sent to remote storage.
  • prometheus_remote_storage_samples_failed_total (counter): Total number of samples that failed to send to remote storage due to non-recoverable errors.
  • prometheus_remote_storage_exemplars_failed_total (counter): Total number of exemplars that failed to send to remote storage due to non-recoverable errors.
  • prometheus_remote_storage_metadata_failed_total (counter): Total number of metadata entries that failed to send to remote storage due to non-recoverable errors.
  • prometheus_remote_storage_samples_retries_total (counter): Total number of samples that failed to send to remote storage but were retried due to recoverable errors.
  • prometheus_remote_storage_exemplars_retried_total (counter): Total number of exemplars that failed to send to remote storage but were retried due to recoverable errors.
  • prometheus_remote_storage_metadata_retried_total (counter): Total number of metadata entries that failed to send to remote storage but were retried due to recoverable errors.
  • prometheus_remote_storage_samples_dropped_total (counter): Total number of samples which were dropped after being read from the WAL before being sent to remote_write because of an unknown reference ID.
  • prometheus_remote_storage_exemplars_dropped_total (counter): Total number of exemplars which were dropped after being read from the WAL before being sent to remote_write because of an unknown reference ID.
  • prometheus_remote_storage_enqueue_retries_total (counter): Total number of times enqueue has failed because a shard’s queue was full.
  • prometheus_remote_storage_sent_batch_duration_seconds (histogram): Duration of send calls to remote storage.
  • prometheus_remote_storage_queue_highest_sent_timestamp_seconds (gauge): Unix timestamp of the latest WAL sample successfully sent by a queue.
  • prometheus_remote_storage_samples_pending (gauge): The number of samples pending in shards to be sent to remote storage.
  • prometheus_remote_storage_exemplars_pending (gauge): The number of exemplars pending in shards to be sent to remote storage.
  • prometheus_remote_storage_shard_capacity (gauge): The capacity of shards within a given queue.
  • prometheus_remote_storage_shards (gauge): The number of shards used for concurrent delivery of metrics to an endpoint.
  • prometheus_remote_storage_shards_min (gauge): The minimum number of shards a queue is allowed to run.
  • prometheus_remote_storage_shards_max (gauge): The maximum number of a shards a queue is allowed to run.
  • prometheus_remote_storage_shards_desired (gauge): The number of shards a queue wants to run to be able to keep up with the amount of incoming metrics.
  • prometheus_remote_storage_bytes_total (counter): Total number of bytes of data sent by queues after compression.
  • prometheus_remote_storage_metadata_bytes_total (counter): Total number of bytes of metadata sent by queues after compression.
  • prometheus_remote_storage_max_samples_per_send (gauge): The maximum number of samples each shard is allowed to send in a single request.
  • prometheus_remote_storage_samples_in_total (counter): Samples read into remote storage.
  • prometheus_remote_storage_exemplars_in_total (counter): Exemplars read into remote storage.


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"

// Configure a prometheus.scrape component to send metrics to
// prometheus.remote_write component.
prometheus.scrape "demo" {
  targets = [
    // Collect metrics from Grafana Agent's default HTTP listen address.
    {"__address__" = ""},
  forward_to = [prometheus.remote_write.staging.receiver]