Appendix D. Probes260Field ValueCritical Minimum Virtual Memory FreeTable D.29. Linux::Virtual Memory settingsD.6. LogAgentThe probes in this section monitor the log files on your systems. You can use them to query logs forcertain expressions and track the sizes of files. For LogAgent probes to run, the nocpulse user mustbe granted read access to your log files.Note that data from the first run of these probes is not measured against the thresholds to preventspurious notifications caused by incomplete metric data. Measurements will begin on the second run.D.6.1. LogAgent::Log Pattern MatchThe LogAgent::Log Pattern Match probe uses regular expressions to match text located within themonitored log file and collects the following metrics:• Regular Expression Matches — The number of matches that have occurred since the probe lastran.• Regular Expression Match Rate — The number of matches per minute since the probe last ran.Requirements — The Red Hat Network Monitoring Daemon (rhnmd) must be running on themonitored system to execute this probe. For this probe to run, the nocpulse user must be grantedread access to your log files.In addition to the name and location of the log file to be monitored, you must provide a regularexpression to be matched against. The expression must be formatted for egrep, which is equivalentto grep -E and supports extended regular expressions. This is the regular expression set for egrep:^ beginning of line$ end of line. match one char* match zero or more chars[] match one character set, e.g. '[Ff]oo'[^] match not in set '[^A-F]oo'+ match one or more of preceding chars? match zero or one of preceding chars| or, e.g. a|b() groups chars, e.g., (foo|bar) or (foo)+WarningDo not include single quotation marks (') within the expression. Doing so causes egrep tofail silently and the probe to time out.Field ValueLog file* /var/log/messagesBasic regular expression*
