Clustering

Axon Server Enterprise can be deployed as a cluster of instances (usually 3 or 5) to guarantee high availability. These instances (usually called “nodes”) replicate data between them. The client applications using Axon Server Enterprise are aware of the various nodes in existence and will connect another one if the node they’re currently connected to becomes unreachable. For maximum reliability, we recommend setting up the cluster so that nodes are located in separated data centers. In this setup, even the complete loss of a data center doesn’t cause loss of Axon Server availability or loss of data.

Multi-Context

Axon Server Enterprise allows the definition of an arbitrary number of logical contexts on a single cluster. This feature is comparable to defining multiple logical databases on a single RDBMS instance. It allows for strong segregation without incurring the overhead of deploying and managing a full instance in each case. There are many potential use cases for this feature. Axon Server contexts may be used for “bounded contexts” in the DDD sense, which has given the feature its name. Customers also use this feature for multi-tenancy (context per tenant), access control, and differentiated retention policies.