When the on demand router (ODR)
processes a request, it obtains the session affinity descriptor policy
of the cluster to which the server belongs. If you changed the default
settings for any middleware servers, you might need to update the
middleware descriptor properties so that the ODR can obtain the descriptor
policy. In most cases, the on demand router
(ODR) does not require configuration to support HTTP session affinity.
However, some special cases exist where you must configure the ODR
to learn about backup servers that the back end servers might be setting
on the session affinity cookie.
Before you begin
The servers in your configuration must
be in a generic server cluster or a dynamic cluster. You can use passive
affinity with a static cluster.
About this task
Passive HTTP session affinity is used
in the following situations:
- When the ODR routes to servers that are not running WebSphere® Application Server middleware products.
- When the ODR routes to WebSphere Application Server application
servers that are in different core groups that are not connected by
the core group bridge.
- When the application uses Java™ 2
Platform, Enterprise Edition (J2EE) HTTP session affinity
that is not standard. For example, the application's session ID cookie
name is something other than JSESSIONID.
Procedure
- If any of the default
values for the server have changed, modify the session affinity descriptor.
In the
administrative console, click System administration > Middleware
descriptors > middleware_server > default.
- Define the session affinity descriptor properties.
Modify the values for any of the following fields
that apply:
- Learn
clone IDs
- Cookie
names
- URL rewrite
- Clone ID separator
- Alternate clone ID separator
- Affinity mode
- Optional: You can create
a cell-wide custom property, HttpAffinityPolicy.cookie_name.cell_name.cluster_name,
to specify session ID cookie names as something other
than JSESSIONID.
- In the administrative console, click .
- Set the HttpAffinityPolicy.cookie_name.cell_name.cluster_name custom
property at the following levels, which are listed in order of preference:
- Web module
- Application
- Server
- Cluster
- Click Apply and save your changes.
Any changes are picked up dynamically; you do not need to restart
the cell.
Results
When the ODR processes a request, it obtains the session
affinity descriptor policy that is configured for the cluster to which
the server belongs. The method in which the server clone identification
is obtained depends on the property values of the policy attributes.