Appendix D. Probes254While adding probes, select meaningful thresholds that, when crossed, notify you and youradministrators of problems within your infrastructure. Timeout periods are entered in seconds unlessotherwise indicated. Exceptions to these rules are noted within the individual probe references.ImportantSome probes have thresholds based on time. In order for such CRITICAL and WARNINGthresholds to work as intended, their values cannot exceed the amount of time allottedto the timeout period. Otherwise, an UNKNOWN status is returned in all instances ofextended latency, thereby nullifying the thresholds. For this reason, Red Hat stronglyrecommends ensuring that timeout periods exceed all timed thresholds.Remember that Red Hat recommends running your probes without notifications for a time to establishbaseline performance for each of your systems. Although the default values provided for probes maysuit your needs, every organization has a different environment that may require altering thresholds.D.2. Apache 1.3.x and 2.0.xThe probes in this section may be applied to instances of the Apache Web server. Although the defaultvalues presume you will apply these probes using standard HTTP, you may also use them over secureconnections by changing the application protocol to https and the port to 443.D.2.1. Apache::ProcessesThe Apache::Processes probe monitors the processes executed on an Apache Web server andcollects the following metrics:• Data Transferred Per Child — Records data transfer information only on individual children. A childprocess is one that is created from the parent process or another process.• Data Transferred Per Slot — The cumulative amount of data transferred by a childprocess that restarts. The number of slots is configured in the httpd.conf file using theMaxRequestsPerChild setting.The ExtendedStatus directive in the httpd.conf file of the Web server must be set to On for thisprobe to function properly.Field ValueApplication Protocol* httpPort* 80Pathname* /server-statusUserAgent* NOCpulse-ApacheUptime/1.0UsernamePasswordTimeout* 15Critical Maximum Megabytes Transferred Per ChildWarning Maximum Megabytes Transferred Per ChildCritical Maximum Megabytes Transferred Per Slot
