[AIX Solaris HP-UX Linux Windows][z/OS]

Intelligent Management for web servers overview

Intelligent Management increases the quality of service and decreases the total cost of ownership for your middleware.

[z/OS]Restriction: Intelligent Management requires that all configurations support User Datagram Protocol (UDP) traffic. However, Sysplex Distributor does not support UDP traffic in all configurations. When you use Sysplex Distributor for a mobile deployment manager in a configuration that includes Intelligent Management, the TCP/IP stack of the deployment manager must own Sysplex Distributor. This setup allows UDP traffic to flow and Intelligent Management to work properly. You can change the ownership of Sysplex Distributor by issuing a VARY TCPIP,,SYSPLEX,DEACTIVATE command.
Attention: Intelligent Management capabilities are only available for Apache or IBM HTTP servers in managed and unmanaged nodes.
By enabling Intelligent Management for your web server, the following capabilities become available for the web server plug-in:
  • Automatic routing: The web server plug-in automatically recognizes application server events (create, delete, start, or stop), application events (start, stop, update), virtual host updates, session affinity configuration changes, and other events which affect routing.
  • Routing information and statistics: You can retrieve routing information and per-application and per-server statistics. If the Apache mod_status module is enabled, the WebSphere® Application Server plug-in with Intelligent Management enabled adds WebSphere Application Server specific status information to http://your_host/server-status.
    Note: If multiple child processes are configured in Apache, the statistics that are presented are only applicable to the single child process that handles the current server-status request.
  • Application edition routing rules: Routing rules that are associated with an application are automatically enforced by the plug-in to route to the appropriate application edition.
  • Edition aware routing: The plug-in maintains continuous availability during application edition rollouts.
  • Node and server maintenance mode routing: When a node or an application server maintenance mode is set, the plug-in automatically routes the requests that are based on the mode.
  • Multi-cell routing: The plug-in routes to multiple cells. The same application URL must not be exported by multiple cells.
  • Highly available connection to each cell. The plug-in connects to a REST service in each cell.  The REST service endpoint is available in the deployment manager and in each node agent via the XD_AGENT port. When a connection failure occurs, the plug-in automatically fails over to another REST service endpoint.
  • Edition aware caching: The Edge Side Include (ESI) cache in the plug-in is aware of the edition to which the request is targeted. The edition is used to form the key when both storing and retrieving cache entries.
  • Weighted Least Outstanding Requests (WLOR) load balancing: This load balancing algorithm quickly responds to application server slow down or hang.
  • Automatically adapt to dynamically changing server weights: The plug-in recognizes dynamically changing server weights and automatically uses these weights in load balancing.
  • Intelligent Management health policies: The plug-in supports the excessive request timeout and excessive response time health policies by alerting the health controller when a configured threshold is exceeded. Health policies that do not involve the on demand router (ODR), such as excessive memory usage, and custom health conditions, are available in the web server plug-in.
  • Per-request conditional tracing: Use the plug-in to enable tracing of specific requests.
All of these capabilities are also available via the ODR. However, the ODR is stabilized.
The following capabilities are not available in the plug-in. Use the ODR for the following scenarios:
  • ODR routing rules.
  • CPU overload protection. This feature throttles traffic when the CPU utilization exceeds a configured threshold on an application server host.
  • Memory overload protection. This feature throttles traffic when the heap utilization exceeds a configured threshold in the application server.
  • Request prioritization. To learn about request prioritization, read the Overview of request flow prioritization.
  • Highly available deployment manager.
  • Classification that is based on the user identity in a Lightweight Third Party Authentication (LTPA) token.
  • Lazy start for dynamic clusters.
  • Workload and storm-drain health policies.
When Intelligent Management is enabled in the WebSphere plug-in, routing information is not defined in the plugin-cfg.xml file. Instead, the plug-in connects to a REST service to dynamically gather routing information for one or more WebSphere cells. The following diagram is an overview of how Intelligent Management works for Apache and IHS.
Intelligent Management on Apache and IHS

The Intelligent Management daemon process is a single highly available process, which starts automatically when Intelligent Management is enabled. Each child worker process connects to the Intelligent Management daemon process to get routing information. The Intelligent Management daemon connects to an Intelligent Management REST service via XD_AGENT port of the deployment manager and each node agent. The Intelligent Management daemon process connects to only one REST service at a time per cell. If the process that the Intelligent Management daemon is connected to stops or fails, the Intelligent Management daemon connects to another process hosting the Intelligent Management REST service. A child worker process does not connect directly to the Intelligent Management REST service; only the Intelligent Management daemon process connects to the Intelligent Management REST service. When Intelligent Management is enabled, the plugin-cfg.xml file is populated with endpoint information for all XD_AGENT ports: for the deployment manager and for each node agent. The plug-in requires this data to discover routing information in a highly available manner. After the Intelligent Management daemon connects to an Intelligent Management REST service and retrieves the initial routing information for the cell, the daemon immediately issues another request, which blocks until a change that affects routing occurs. In this way, the plug-in is immediately notified of configuration or state changes, which are important for routing.