Managed and unmanaged nodes
A node is a logical grouping of managed servers.
A node usually corresponds to a logical or physical computer system with a distinct IP host address. Nodes cannot span multiple computers.
By default, node names are based on the host name of the computer, for example MyHostNode01.
(iSeries) The node name for the default profile created during product installation is the short host name of the server. When we create a new profile that is not a deployment manager profile, the node name defaults to hostName_profileName.
Nodes can be managed or unmanaged. An unmanaged node does not have a node agent or administrative agent to manage its servers, whereas a managed node does. Both application servers and supported web servers can be on unmanaged or managed nodes.
A stand-alone application server is an unmanaged node. The application server node becomes a managed node when it is either federated into a cell or registered with an administrative agent.
When we create a managed node by federating the application server node into a deployment manager cell, a node agent is automatically created. The node agent process manages the application server configurations and servers on the node.
When we create a managed node by registering an application server node with an administrative agent, the application server must be an unfederated application server node. The administrative agent is a single interface that monitors and controls one or more application server nodes so we can use the application servers only to run the applications. Using a single interface reduces the overhead of running administrative services in every application server.
A managed node in a cell can have WebSphere Application Server, Java Message Service (JMS) servers (on Version 5 nodes only), web servers, or generic servers. A managed node that is not in a cell, but is instead registered to an administrative agent, can have application servers, web servers, and generic servers on the node.
An unmanaged node can exist in a cell as long as the unmanaged node only has a supported web server defined on it. Unsupported Web servers can be on unmanaged nodes only and cannot be in a cell.
Use the command line only to create a managed node registered to an administrative agent.
Create a managed node in a cell in one of the following ways:
- Administrative console
- Command line
- Administrative script
- Java program
Each of these methods for adding a node to a WAS ND cell includes the option of specifying a target node group for the managed node to join. If we do not specify a node group, or we do not have the option of specifying a node group, the default node group of DefaultNodeGroup is the target node group.
(ZOS) On the z/OS system, the default DefaultNodeGroup node group is the sysplex node group for the deployment manager node and any other node in the cell from the same sysplex. A z/OS system node from a different sysplex cannot be a member of this node group and must be a member of a sysplex node group for its sysplex.
Whether we specify an explicit node group for a cell or accept the default, the node group membership rules must be satisfied. If the node we are adding does not satisfy the node group membership rules for the target node group, the add node operation fails with an error message.
Each managed node that is joined to a cell must be a member of a node group. However, a managed node registered to an administrative agent cannot be a member of a node group.
The concepts of managed and unmanaged nodes are not applied to the registration of nodes to the job manager.
Administrative functions for web server nodes supports the following:
- Basic administrative functions for all supported web servers. For example, the generation of a plug-in configuration can be performed for all web servers. However, propagation of a plug-in configuration to remote web servers is supported only for IBM HTTP Servers defined on an unmanaged node. If the web server is defined on a managed node, propagation of the plug-in configuration is done for all the web servers using node synchronization. The web server plug-in configuration file is created according to the web server definition and is based on the list of applications deployed on the web server. We can also map all supported Web servers as potential targets for the modules during application deployment.
- Some additional administrative console tasks for IBM HTTP Servers on managed and unmanaged nodes. For instance, we can start IBM HTTP Servers, stop them, terminate them, display their log files, and edit their configuration files.
Node groups Administrative agent Add, manage, and remove nodes Administer nodes and resources Implement a web server plug-in Install IBM HTTP Server View, add, and delete node group members