Like the check engine light for a vehicle, the OpenEdge HealthScanner alerts system administrators of potential problems with an instance so that the server can be taken out of service before a failure occurs. The OpenEdge HealthScanner is not designed to research or resolve the problem; it flags a server that falls below a healthy threshold.

Designed for system administrators, the OpenEdge HealthScanner checks the overall health of a server, and assigns a score from 0-100% as well as a status code. System administrators configure an acceptable threshold for a server to be considered in operational good health. Servers with scores below the threshold can be taken out of service by an elastic load balancer (ELB). The ELB can terminate the server, and can dynamically replace the failing server before any disruption of service happens.

The following is an example of the Amazon Web Service (AWS) Cloud Health Check configuration for a server that is part of an Auto Scaling group. Use the AWS Health Check ping target field to poll the health of a server.

If the ping returns a status code of 500, then the server is automatically terminated, and the new server is brought online, providing continuous availability of a healthy server to respond to client requests.

Note: The HealthScanner is limited to cloud operating systems for Windows and Linux.

How is the data collected?

The HealthScanner consists of a health collector that collects data from a variety of probes. Each probe checks a specific health value of the server, just like the sensors in a vehicle checking the engine, oil, gas, and tire pressure levels.

The HealthScanner is a Tomcat service with its own HTTP port, thread pool, and configuration. As a stand-alone service, it returns probe results even when the main Tomcat connector is not able to respond. This feature is an opt-in service, to avoid unnecessary use of system resources.