========================== CrateDB Prometheus Adapter

|version| |ci-tests| |license|

This is an adapter that accepts Prometheus remote read/write requests, and sends them to CrateDB. This allows using CrateDB as long term storage for Prometheus.

Along the lines, the program also exports metrics about itself, using the cratedb_prometheus_adapter_ prefix.

Setup

The CrateDB Prometheus Adapter is offered in two different distribution variants. You can choose freely which fits your needs best.

• Native release archives_ for Linux, Darwin and Windows platforms.
• Public Docker image ghcr.io/crate/cratedb-prometheus-adapter_.

.. _Native release archives: https://cdn.crate.io/downloads/dist/prometheus/ .. _ghcr.io/crate/cratedb-prometheus-adapter: https://ghcr.io/crate/cratedb-prometheus-adapter

Usage

Create the following table in your CrateDB database:

.. code-block:: sql

CREATE TABLE "metrics" ( "timestamp" TIMESTAMP, "labels_hash" STRING, "labels" OBJECT(DYNAMIC), "value" DOUBLE, "valueRaw" LONG, "day__generated" TIMESTAMP GENERATED ALWAYS AS date_trunc('day', "timestamp"), PRIMARY KEY ("timestamp", "labels_hash", "day__generated") ) PARTITIONED BY ("day__generated");

Depending on data volume and retention you might want to optimize your partitioning scheme and create hourly, weekly, ... partitions.

Then run the adapter::

# When using the single binary
./cratedb-prometheus-adapter

# When using Docker
docker run -it --rm --publish=9268:9268 ghcr.io/crate/cratedb-prometheus-adapter

By default the adapter will listen on port 9268 and will use a built-in configuration as outlined in the next section. This and more is configurable via command line flags, which you can see by passing the -h flag.

The CrateDB endpoints are provided in a configuration file, which defaults to config.yml (-config.file flag). The included example configuration file forwards samples to a CrateDB running on localhost on port 5432.

CrateDB Adapter Endpoint Configuration

The path to the YAML-based configuration file can be provided by using the -config.file command line option. The settings describe the CrateDB endpoints the adapter will write to.

If multiple endpoints are listed, the adapter will load-balance between them. The options (with one example endpoint) are as below:

.. code-block:: yaml

cratedb_endpoints:

• host: "localhost" # Host to connect to (default: "localhost"). port: 5432 # Port to connect to (default: 5432). user: "crate" # Username to use (default: "crate") password: "" # Password to use (default: ""). schema: "" # Schema to use (default: ""). connect_timeout: 10 # TCP connect timeout (seconds) (default: 10). max_connections: 5 # The maximum number of concurrent connections (default: 5). enable_tls: false # Whether to connect using TLS (default: false). allow_insecure_tls: false # Whether to allow insecure / invalid TLS certificates (default: false).

Prometheus Configuration

In order to forward write and read requests to the CrateDB adapter, adjust your prometheus.yml like:

.. code-block:: yaml

remote_write: - url: http://localhost:9268/write remote_read: - url: http://localhost:9268/read

The adapter also exposes Prometheus metrics on /metrics, which can be scraped in the usual way.

Running as service

In order to run cratedb-prometheus-adapter as a system service on Linux, the repository provides configuration files to configure the program as a systemd service unit. This section outlines how to apply that configuration.

Copy <config.yml>_ to /etc/cratedb-prometheus-adapter/config.yml and adjust as needed.

Copy <systemd/cratedb-prometheus-adapter.service>_ to /etc/systemd/system/cratedb-prometheus-adapter.service or just link the service file by running: sudo systemctl link $(pwd)/cratedb-prometheus-adapter.service and run::

systemctl daemon-reload

Change flag-based configuration by changing the settings in /etc/default/cratedb-prometheus-adapter based on the <systemd/cratedb-prometheus-adapter.default>_ template. After that you can::

systemctl start cratedb-prometheus-adapter
systemctl enable cratedb-prometheus-adapter

.. |version| image:: https://img.shields.io/github/tag/crate/cratedb-prometheus-adapter.svg :alt: Version :target: https://github.com/crate/cratedb-prometheus-adapter

.. |ci-tests| image:: https://github.com/crate/cratedb-prometheus-adapter/workflows/Tests/badge.svg :alt: CI status :target: https://github.com/crate/cratedb-prometheus-adapter/actions?workflow=Tests

.. |license| image:: https://img.shields.io/badge/License-Apache%202.0-blue.svg :alt: License: Apache 2.0 :target: https://opensource.org/licenses/Apache-2.0