WAS ND Architecture main components

Deployment Manager
The Deployment Manager process provides a centralized administration mechanism for all nodes in a cell, including all WAS processes on each nodes as well as the cell configuration repository for both WAS and installed applications. The Dmgr works in conjunction with each node agent to control processes on each node and to maintain the configuration for each node. By providing a central point for management, the Dmgr allows you to control cells consisting of numerous nodes and in turn nodes running one or more server.

Node agent

A node agent is a local administrative agent process running on every node in the cell. The node agent server acts as local proxy for deployment manager, providing capability to manage servers and the configuration for each servers defined on a node. The node agent is intended solely as an administative process, the node agent does not provide a J2EE application runtime.If you use wsadmin tool to directly connect to node agent then you will only get access to AdminControl functions, AdminConfig and AdminApp functions are not available to safeguard against accidental changing of the configuration data

Application server
Application server in ND environment is same as the application server in standalone environment, but the difference is that it does not have a Administrative console application, instead configuration for the application server is managed centerally by the Deployment Manager. If you use wsadmin tool to directly connect to application server then you will only get access to AdminControl functions, AdminConfig and AdminApp functions are not available to safeguard against accidental changing of the configuration data

JMS Server
This server hosts the WebSphere Embedded messaging service on a node. In WAS ND there can be one JMS server node.

Admin Client
WAS provides two different admin clients, one is Web based Admin console and other is wasadmin command which is a command line tool