Intelligent Management increases
the quality of service and decreases the total cost of ownership for
your middleware. Intelligent Management capabilities
are 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 the above 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 goes above a configured threshold on an application
server host.
- Memory overload protection. This feature throttles traffic when
the heap utilization goes above 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.

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.