<!--
Gnucomo - Gnu Computer Monitoring Tutorial
Original author : Peter Roozemaal
- Version : $Revision: 1.3 $
+ Version : $Revision: 1.4 $
This document is prepared for XMLDoc. Transform to HTML,
LaTeX, Postscript or plain text with XMLDoc utilities and
</para>
<section>
+<heading>System resources</heading>
+<para>
+By monitoring the resources of a system, such as memory, cpu, file systems and
+network interfaces, you can keep track on the system's performance and capacity.
+The utilization of these resources varies frequently over time.
+Viewing the values of resource properties provides an excelent insight in
+the system's behaviour.
+Gnucomo can maintain a record of the system resources by using DYNAMIC properties
+in parameters.
+You can define classes of parameters with properties that will reflect the state
+of your systems and feed the numbers into the Gnucomo database by using scripts
+that extract the information from a system and convert this into XML format.
+</para>
+<para>
+As an example, consider the processing load of a system.
+Two metrics can be of interest to keep an eye on the system load:
+The total number of processes and the number of runnable processes.
+These numbers are easily obtained with standard UNIX commands <code>ps</code>
+and <code>uptime</code>.
+To maintain this in Gnucomo, a <emph>class</emph> is needed to define the
+properties we want to maintain.
+For this example, we create a class <strong>systemload</strong> with the properties
+<strong>processes</strong> and <strong>runqueue</strong>.
+Note that both these properties are DYNAMIC.
+The properties for the <strong>systemload</strong> class can be defined by using
+Gnucomo's web interface or typing SQL statements directly into the database:
+</para>
+<verbatim>
+INSERT INTO parameter_class (name, property_name, description, property_type, min, max, notify)
+ VALUES ('systemload', 'processes', 'Total number of processes', 'DYNAMIC', 0, 1000, 'f');
+INSERT INTO parameter_class (name, property_name, description, property_type, min, max, notify)
+ VALUES ('systemload', 'runqueue', '5 minute average length of the run queue', 'DYNAMIC', 0, 5.00, 'f');
+</verbatim>
+<para>
+When the class is defined in the Gnucomo database, we are ready to feed the
+information into Gnucomo through <code>gcm_input</code>.
+The following shell script will create the appropriate XML document with the
+parameter values:
+</para>
+<verbatim>
+#!/bin/sh
+#
+# Gnucomo system load report.
+#
+# Create a parameter report with two values:
+# The total number of processes and the 5-min load average.
+#
+
+
+HOST=`hostname`
+TIME=`date`
+
+echo "<?xml version='1.0'?>"
+echo "<gcmt:message xmlns:gcmt='http://gnucomo.org/transport/'>"
+echo " <gcmt:header>"
+echo " <gcmt:messagetype>XML</gcmt:messagetype>"
+echo " <gcmt:hostname>$HOST</gcmt:hostname>"
+echo " <gcmt:time>$TIME</gcmt:time>"
+echo " </gcmt:header>"
+echo " <gcmt:data>"
+
+echo " <gcmt:parameters gcmt:class='systemload'>"
+
+PROCESSES=`ps ax|wc -l`
+LOADAV=` uptime|cut -d ' ' -f 13|tr -d ,`
+
+echo "<gcmt:parameter name='Load'>"
+echo " <gcmt:description>System processing load</gcmt:description>"
+echo " <gcmt:property name='processes'>$PROCESSES</gcmt:property>"
+echo " <gcmt:property name='runqueue'>$LOADAV</gcmt:property>"
+echo "</gcmt:parameter>"
+
+echo " </gcmt:parameters>"
+echo " </gcmt:data>"
+echo "</gcmt:message>"
+</verbatim>
+<para>
+Filesystems are predefined in Gnucomo.
+Gcm_input understands the output of most <code>df</code> implementations directly.
+The following examples show how to feed filesystem information into Gnucomo:
+</para>
+<example>
+df -lPk -x tmpfs | gcm_input -h `hostname`
+df -lPi -x tmpfs | gcm_input -h `hostname`
+</example>
+<para>
+Make sure to add the <code>-k</code> option so <code>df</code> reports
+the filesystem sizes in kilobytes.
+</para>
+</section>
+
+<section>
<heading>Installed packages</heading>
<para>
projects / gnucomo.git / blobdiff