Node
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. Node names usually are identical to the host name for the computer.
Nodes in the network deployment topology can be managed or unmanaged. Two types of managed nodes exist while one type of unmanaged node exists.
One type of managed node has a node agent which manages all servers on a node, whether the servers are WAS appservers, JMS servers (on V5 nodes only), Web servers, or generic servers. The node agent represents the node in the management cell. A deployment manager manages this type of managed node. The other type of managed node has no node agent. This type of managed node is defined on a standalone Application Server. The deployment manager cannot manage this standalone Application Server. A standalone Application Server can be federated. When it is federated, a node agent is automatically created. The node becomes a managed node in the cell. The deployment manager manages this node.
An unmanaged node does not have a node agent to manage its servers. Unmanaged nodes can have server definitions such as Web servers in the WAS topology. Unmanaged nodes can never be federated. That is, a node agent can never be added to an unmanaged node.
A supported Web server can be on a managed node or an unmanaged node. We can define only one Web server to a standalone WAS node. This Web server is defined on an unmanaged node. We can define Web servers to the deployment manager. These Web servers can be defined on managed or unmanaged nodes.
WAS supports basic administrative functions for all supported Web servers. For example, 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 that are 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 by using node synchronization. The Web server plug-in configuration file is created according to the Web server definition and is created based on the list of applications that are deployed on the Web server. We can also map all supported Web servers as potential targets for the modules during application deployment.
WAS supports some additional administrative console tasks for IBM HTTP Servers on managed and unmanaged nodes. For instance, one can start IBM HTTP Servers, stop them, terminate them, display their log files, and edit their configuration files.
We can add managed and unmanaged nodes to a network deployment cell in one of the following ways:
- Administrative console
- Command line (managed nodes only)
- Administrative script
- Java program
Each of these methods for adding a managed node to a network deployment cell includes the option of specifying a target node group for the managed node to join. If you do not specify a node group, or you do not have the option of specifying a node group, the default node group of DefaultNodeGroup is the target node group.
Whether you specify an explicit node group or accept the default, the node group membership rules must be satisfied. If the node you are adding does not satisfy the node group membership rules for the target node group, the add node operation fails with an error message.
See Also
Node group
Related Tasks
Manage nodes
Setting up the administrative architecture
Communicating with Web servers
Installing IBM HTTP Server