Every system on which you install a module in the Advisors suite, where the module uses an Advisors Platform database, is a node in a cluster. It can be a physical computer, or a virtual machine on a VM host. It has an IP address.
A node in a cluster is also referred to as a member of the cluster.
Even if you install Advisors on only one system, that system is a node in a cluster containing that one system.
A module is an application in the Advisors suite that you can install separate from other applications. For example, WA Server is a module, and Contact Center Advisor XML Generator is a module.
Members of the cluster communicate to share data that is cached in memory. They also communicate via messages, to perform workflows that require more than one module.
A system that is a node in a cluster can run one Advisors module, or more than one Advisors module.
For example, the WA Server and WA Web Services are two modules, and you can install both on the same node. Alternatively, you can install the WA server on one cluster member, and WA web services on another cluster member.
Another example: WA Server and CCAdv XML Generator are two modules, and you can install them both on the same node or on different nodes. In the first case, you would have one cluster member, and in the second case, you would have two. See diagrams of possible configurations.
For instructions about how to modify a cluster after you have installed Advisors, see Change Advisors Cluster Membership.