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This guide explains how information, such as CPU usage, can be gathered from the Cisco box via SNMP protocol. We use such information as a base for RRD graphs. - Cisco ACE box - Dedicated Server * with: apache2, snmp, RRDs, perl, mrtg, mrtg-rrd script for displaying charts. - If you want to monitor loadbalancing: you need also a loadbalanced serverfarm configured on ACE. In this example we use safer version of SNMP - v.3. It doesn't use community name - requires username and password authentication. First, create snmp-server with user/password access: username: MonitorUser? group: Network-Monitor? pass: test-pass rbx-99-6k-ace-1/vrack2070(config)# snmp-server user MonitorUser? Network-Monitor? auth sha pass-monitor Now we have to create a class map for SNMP traffic incoming from our management server (IP: 188.165.213.17): rbx-99-6k-ace-1/vrack2070(config)# class-map type management match-all SNMP-ALLOW_CLASS 2 match protocol snmp source-address 188.165.213.17 255.255.255.255 policy map: rbx-99-6k-ace-1/vrack2070(config)# policy-map type management first-match SNMP_POLICY class SNMP-ALLOW_CLASS permit And finally, you apply policy-map to the external vlan interface: rbx-99-6k-ace-1/vrack2070(config)# interface vlan 270 service-policy input SNMP_POLICY Now we move to manage the server: 188.165.213.17 Firstly, check if there is an access to the ACE box via SNMP: [root@server ~] snmpwalk -v 3 -l AuthNoPriv? -u MonitorUser? -a sha -A pass-monitor 188.165.125.125 1.3.6.1.2.1.1 SNMPv2-MIB::sysDescr.0 = STRING: Application Control Engine Service Module SNMPv2-MIB::sysObjectID.0 = OID: SNMPv2-SMI::enterprises.9.1.730 DISMAN-EVENT-MIB::sysUpTimeInstance = Timeticks: (2766993305) 320 days, 6:05:33.05 SNMPv2-MIB::sysContact.0 = STRING: SNMPv2-MIB::sysName.0 = STRING: rbx-99-6k-ace-1 ... We've got some basic information using OID: 1.3.6.1.2.1.1 (this is system object in Cisco Object Tree - see documents) such as a system description, uptime and others. Now we try to gather those data using a simple perl script: #!/usr/bin/perl use strict; use warnings; use Net::SNMP qw(:snmp); my %oids = ( sysUpTimeInstance => '1.3.6.1.2.1.1.3.0', sysDescr => '1.3.6.1.2.1.1.1.0', cpmCPUTotal1minRev=> '1.3.6.1.4.1.9.9.109.1.1.1.1.7.1', cpmCPUTotal5minRev=> '1.3.6.1.4.1.9.9.109.1.1.1.1.8.1' ); my ($session, $err) = Net::SNMP->session( -version => '3', -hostname => '188.165.125.125', -username => 'MonitorUser', -authpassword => 'pass-monitor', -authprotocol => 'sha' ); die 'Error: '. $err unless $session; my $result = $session->get_request( -varbindlist => [values %oids] ); unless(defined $result) { warn $session->error(); $session->close(); exit 1; } print "Report from ACE. Example info:\n"; foreach(sort keys %oids){ print $_ . ': ' . $result->{$oids{$_}} . "\n"; } $session->close(); exit 0; And the result: [root@server ~] perl script.pl Report from ACE. Example info: cpmCPUTotal1minRev: 6 cpmCPUTotal5minRev: 4 sysDescr: Application Control Engine Service Module sysUpTimeInstance: 320 days, 06:12:51.79 Then we can compare this information with the "real ones": rbx-99-6k-ace-1/vrack2070# sh processes cpu CPU utilization for five seconds: 3%; one minute: 6%; five minutes: 4% PID Runtime(ms) Invoked uSecs 1Sec 5 Sec 1 Min 5 Min Process 1 412654 5652836 72 0.0 0.0 % 0.0 % 0.0 % init 2 14 2946 5 0.0 0.0 % 0.0 % 0.0 % keventd 3 40191 17823851 2 0.0 0.0 % 0.0 % 0.0 % ksoftirqd_CPU0 4 70517 17202179 4 0.0 0.0 % 0.0 % 0.0 % ksoftirqd_CPU1 5 0 1 10 0.0 0.0 % 0.0 % 0.0 % kswapd ... As we can see CPU utilization data are the same (one and five minute periods). Now we're going to configure mrtg and present cpu utilization (one and five min. periods) on the charts. MRTG example configuration for SNMP v3: WorkDir: /home/ovh/aceMonitor/www LogFormat: rrdtool PathAdd: /usr/bin/ LibAdd: /usr/share/perl5 Options[$]: noborder nobanner growright TimeStrFmt[_]: %Y-%m-%d %H:%M:%S Target[ace-2070-load]: 1.3.6.1.4.1.9.9.109.1.1.1.1.7.1&1.3.6.1.4.1.9.9.109.1.1.1.1.8.1:public@188.165.125.125 : 3SnmpOptions[ace-2070-load]: authpassword=>'pass-monitor',authprotocol=>'sha',username=>'MonitorUser' noHC[ace-2070-load]: yes SetEnv[ace-2070-load]: MRTG_INT_IP="188.165.125.125" MRTG_INT_DESCR="" MaxBytes[ace-2070-load]: 100 Title[ace-2070-load]: CPU usage for rbx-99-6k-ace-1/vrack2070 PageTop[ace-2070-load]: <h1>CPU usage for rbx-99-6k-ace-1/vrack2070</h1> LegendI[ace-2070-load]: cpu 1min: LegendO[ace-2070-load]: cpu 5min: Options[ace-2070-load]: gauge Ylegend[ace-2070-load]: percent ShortLegend[ace-2070-load]: % Legend1[ace-2070-load]: CPU utilisation 1 min avg Legend2[ace-2070-load]: CPU utilisation 5 min avg enablesnmpv3: yes And the result:  -Cisco SNMP Object Navigator -Cisco Application Control Engine Module Load Balancing Guide -MRTG reference |
