Custom advisor policies

Custom advisor policies help to determine target application server availability. Custom advisors are Java code modules that work within the proxy server to provide information about the application's availability to the proxy server selection code.

Custom advisor policies provide a mechanism to interpret an application protocol response message to determine if an application server, a cluster, or a generic server cluster should be used by the proxy server when requests are made. A custom advisor is able to verify that the application is available, functioning properly, and has access to all required resources.

The proxy server periodically performs an advisor cycle. During an advisor cycle it will call the isUsable() method defined on the custom advisor for each available application server, cluster, and generic server cluster targeted by that custom advisor. The isUsable() method passes an AdvisableServer object, which is used to determine the address, port, and protocol for the targeted application servers, clusters, and generic server clusters.

The custom advisor sends a request to the targets and if communication is successful, then receives their responses. Using the responses, the custom advisor determines if the target is usable or is not usable. If the target is not usable, then the target will be marked as unavailable and will not be used for selection. A target that is marked as unavailable will not be used for selection for this application again, until it is determined to be available by a future advisor cycle. If the target is determined to be usable, a value of true is returned, and the target will continue to be used for selection.

Create custom advisors for the proxy server

Custom advisors collection