- Hewlett-Packard Printer User Guide

Using the Integration Capabilities of the VPO Motif-based GUI

Event Integration Through Messages

Chapter 3 113

Sending Values Over the VPO Monitoring API or Command

VPO provides an API and a command opcmon(1|3) to allow applications

to send monitoring values from the managed nodes to the VPO

management server. This API/command should be used at the managed

nodes for distributed, exception-based management.

The following steps describe the process ﬂow and the interaction

between the monitor agent of VPO (opcmona) running on the managed

node, and the monitoring script or program provided by the user:

1. VPO checks the intervals deﬁned to invoke the monitoring scripts.

2. VPO calls the speciﬁed script or program.

3. As part of the script or program, the actual monitoring values are

collected.

4. The script calls opcmon(1|3) (usually once) to pass the value(s) to the

monitor agent of VPO.

5. The monitor agent checks the value received from opcmon(1|3) and

returns a value to the caller of the script: zero for successful

execution, one for a failure.

6. The monitor agent reads the value against the predeﬁned thresholds

and generates a message if an exception occurs.

7. The return value of opcmon(1|3) is checked in the script and the

processing of the script continues.

VPO checks the exit value from the script and sends an error message if

the script returns an exit value other than zero.