Configuration

To start a Crux node, use the Java API or the Clojure crux.api.

There are different configurations of a Crux node:

Use a cluster node when horizontal scalability is required or when you want the guarantees that Kafka offers in terms of resiliency, availability, and retention of data.

Multiple cluster nodes participate in a cluster using Kafka as the primary store and as the central means of coordination.

The JDBC node is for when you don’t want the overhead of maintaining a Kafka cluster. Read more about the motivations of this setup here.

The Standalone node is where a single Crux instance has everything it needs locally. This is good for experimenting with Crux and for small to medium sized deployments, where running a single instance is permissible.

Crux nodes implement the ICruxAPI interface and are the starting point for making use of Crux. Nodes also implement java.io.Closeable and can therefore be lifecycle managed.

The follow properties are required for any type of Crux Node:

Using a Crux standalone node is the best way to get started. Once you’ve started a standalone Crux instance as described below, you can then follow the getting started example.

When using Crux at scale it is recommended to use multiple Crux nodes connected via a Kafka cluster.

The following properties are required for a Kafka Cluster Node:

JDBC Nodes use next.jdbc internally and pass through the relevant configuration options that you can find here.

Below is the minimal configuration you will need:

Add crux-jdbc to your project dependencies:

Use the API to start a JDBC node, configuring it with the required parameters:

Crux can be used programmatically as a library, but Crux also ships with an embedded HTTP server, that allows clients to use the API remotely via REST.

Set the server-port configuration property on a Crux node to expose a HTTP port that will accept REST requests:

Visit the guide on using the REST api for examples of how to interact with Crux over HTTP.

If you want to experiment with Crux using a demo Docker container from Docker Hub (no JVM/JDK/Clojure install required, only Docker!) then please see the standalone web service example. You can also use this self-contained demonstration image to experiment with the REST API.

Crux provides utility APIs for local backup and restore when you are using the standalone mode. For an example of usage, see the standalone web service example.

An additional example of backup and restore is provided that only applies to a stopped standalone node here.

In a clustered deployment, only Kafka’s official backup and restore functionality should be relied on to provide safe durability. The standalone mode’s backup and restore operations can instead be used for creating operational snapshots of a node’s indexes for scaling purposes.