You deliver your application on several grouped servers, also known as a cluster. Each cluster consists of multiple nodes:
Node: A node is a single instance of a Couchbase Server running on a physical or virtual machine, or other environment.
Cluster: This is a collection of one or more nodes. All nodes in a cluster are identical in function, interfaces, components and systems. Couchbase Server manages data across nodes in a cluster. When you increase the size of a cluster, the cluster scales linearly; that is, there is no hierarchy or parent/child relationships between multiple nodes in a cluster.
Nodes or clusters typically reside on a separate physical machine than your web server. Your Couchbase node/cluster will communicate with your web application via a Couchbase SDK, which we describe in detail in this guide. Your application logic does not need to handle information about nodes or clusters; the Couchbase SDKs are able to automatically communicate with the appropriate Couchbase cluster nodes.