API Gateway Components
API Gateway consists of the following components:
The following table lists the purpose and characteristics of the API Gateway components:
Component | Purpose | Characteristics |
Integration Server | Policy Enforcement Engine |  Stateless engine  Two or more instances can operate as a cluster  Supports vertical and horizontal scaling  It runs an embedded Apache Tomcat server to host API Gateway console UI |
Elasticsearch | Persistence layer for API configurations and API analytics |  Stateful persistence  Externalized Elasticsearch is supported  Needs quorum (odd number of instances) to operate in a cluster Note: Best practice is to separate the API analytics in a dedicated cluster.  Supports horizontal scaling and data- sharing |
Kibana | Dashboard for the API analytics |  Stateless engine  Externalized Kibana is supported  Two instances can operate in a cluster  Scaling more than two is generally not required |
Cluster Coordinator | In-Memory Distributed Caching |  Stateful engine for cluster coordination and service result caching  Two options: Ignite Terracotta Server Array (TSA)  Ignite is embedded and scales as you scale the Integration Server.  TSA operates in an active-passive setup, typically, two instances are sufficient. Scaling more than two is not required and an anti-pattern . |
Note:
All the components can run in containers.
For more information on the supported versions of external Elasticsearch, Kibana, and Terracotta Server Array, see
API Gateway, Elasticsearch, Kibana, and TSA Compatibility
Matrix.