Send Prometheus metrics to Promscale

Promscale can be used as a remote storage for Prometheus and has native support for the Prometheus remote write and read protocols as well as full PromQL support.

Configure Prometheus to read and write data from Promscale

You can configure Prometheus to use Promscale as a remote storage. Open the Prometheus configuration file and add or edit these lines:

  2. remote_write:
  4.   - url: "http://<connector-address>:9201/write"
  6. remote_read:
  8.   - url: "http://<connector-address>:9201/read"
  10.     read_recent: true
important

We highly recommend that you set Prometheus to query data from Promscale for all PromQL queries. To do this, set the read_recent parameter to true.

Configure Prometheus for better performance with Promscale

This section contains information about configuring the Prometheus remote-write settings to maximize performance from Promscale.

Remote-write performance is dependent on queue_config. Changing values in queue_config allows you to change the remote-write component for different scenarios. For most cases, these settings work well:

  2. remote_write:
  4.   remote_timeout: 100s
  6.   queue_config:
  8.     max_samples_per_send: 10000

This section contains further explanation of each parameter.

For more information about Prometheus remote-write configuration, see the Prometheus documentation.

Remote timeout

Set with the remote_timeout field in remote_write.

This parameter corresponds to the timeout value of HTTP POST requests, which carry the samples batch to the remote storage. If Promscale is far from where Prometheus is deployed, or you have a high cardinality of data being ingested, you can set this to remote_timeout: 100s. However, higher values for remote_timeout can be considered, based on the requirements.

Maximum samples per send

Set with the max_samples_per_send field in queue_config.

This parameter is the maximum number of samples that can fit in a single write request to the remote storage system. Samples batch less than max_samples_per_send are sent only when batch_send_deadline expires. Promscale performs better with larger batches, so set the default to max_samples_per_send: 10000.