nextcloud-docs/crate/content.md

What is Crate?

Crate is an Elastic SQL Data Store. Distributed by design, Crate makes centralized database servers obsolete. Realtime non-blocking SQL engine with full blown search. Highly available, massively scalable yet simple to use.

Crate

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How to use this image

docker run -d -p 4200:4200 -p 4300:4300 crate:latest

Attach persistent data directory

docker run -d -p 4200:4200 -p 4300:4300 -v <data-dir>:/data crate

Use custom Crate configuration

docker run -d -p 4200:4200 -p 4300:4300 crate -Des.config=/path/to/crate.yml

Any configuration settings may be specified upon startup using the -D option prefix. For example, configuring the cluster name by using system properties will work this way:

docker run -d -p 4200:4200 -p 4300:4300 crate crate -Des.cluster.name=cluster

For further configuration options please refer to the Configuration section of the online documentation.

Environment

To set environment variables for Crate Data you need to use the --env option when starting the docker image.

For example, setting the heap size:

docker run -d -p 4200:4200 -p 4300:4300 --env CRATE_HEAP_SIZE=32g crate

Multicast

Crate uses multicast for node discovery by default. However, Docker does only support multicast on the same host. This means that nodes that are started on the same host will discover each other automatically, but nodes that are started on different hosts need unicast enabled.

You can enable unicast in your custom crate.yml. See also: Using Crate Data in a Multi Node Setup.