Network Deployment (Distributed operating systems), v8.0 > Secure applications and their environment > Authenticate users > Select an authentication mechanism > Configure LTPA and working with keys > 2. Generate keys manually or automatically, and control the number of active keys. > Work with nodes - groups of managed servers
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.
Nodes can be managed or unmanaged. An unmanaged node does not have a node agent or admin 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 admin agent.
When you create a managed node by federating the application server node into a dmgr cell, a node agent is automatically created. The node agent process manages the application server configurations and servers on the node.
When you create a managed node by registering an application server node with an admin agent, the application server must be an unfederated application server node. The admin agent is a single interface that monitors and controls one or more application server nodes so that you 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 WAS, 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 admin 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.
We can use the command line only to create a managed node that is registered to an admin agent.
We can 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 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 for a cell or accept the default, the node group membership rules must be satisfied. If the node that 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.
Each managed node that is joined to a cell must be a member of a node group. However, a managed node that is registered to an admin 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
WAS supports 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 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 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.
WASsupports some additional administrative console tasks for IBM HTTP Servers on managed and unmanaged nodes. For instance, you can start IBM HTTP Servers, stop them, terminate them, display their log files, and edit their configuration files.
Node groups
Administrative agent
Manage nodes
Administer nodes and resources
Implement a web server plug-in
Install IBM HTTP Server
Add node group members