Messaging system

Different Nuxeo services rely on a messaging system, this is the case for the WorkManager, Nuxeo Stream and the Bulk Service, the PubSub services and the KeyValue Store.

Concepts

When running in cluster mode, the Nuxeo nodes need to communicate so the following services work in a distributed way:

• The WorkManager can distribute its Works among nodes and share a common state.
• Nuxeo Stream and the Bulk Service distribute processing among nodes and handle failover. It is used by critical features such as Document trashing, CSV export, document deletion, etc.
• The KeyValue Store is shared by all nodes and used by different services like the Transient Store.
• The PubSub Service is used to distribute cache invalidation among nodes.

Requirements

Kafka is required as a messaging system in Nuxeo LTS 2023 for all the above services except for the KeyValue Store which relies on the repository database.