Using MRTG for monitoring host CPU, memory, disk etc.

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Using MRTG for monitoring host CPU, memory, disk etc.

Use of cacti is recommended over trying to use MRTG

First configure SNMP server on Linux host as explained at SNMP server configuration for Linux hosts. Then use following steps to monitor CPU, memory, disk etc.:

1. Use following configuration file:

   
   #
   # File: /etc/mrtg/server-info.cfg
   #
   # Configuration file for non bandwidth server statistics
   #
   
   #
   # Define global options
   #
   
   LoadMIBs: /usr/share/snmp/mibs/UCD-SNMP-MIB.txt,/usr/share/snmp/mibs/TCP-MIB.txt
   workdir: /var/www/html/127.0.0.1-stats/
   
   
   #
   # CPU Monitoring
   # (Scaled so that the sum of all three values doesn't exceed 100)
   #
   
   Target[server.cpu]:ssCpuRawUser.0&ssCpuRawUser.0:public@localhost + ssCpuRawSystem.0&ssCpuRawSystem.0:public@localhost + ssCpuRawNice.0&ssCpuRawNice.0:public@localhost
   Title[server.cpu]: Server CPU Load
   PageTop[server.cpu]: <h1>CPU Load - System, User and Nice Processes</h1>
   MaxBytes[server.cpu]: 100
   ShortLegend[server.cpu]: %
   YLegend[server.cpu]: CPU Utilization
   Legend1[server.cpu]: Current CPU percentage load
   LegendI[server.cpu]: Used
   LegendO[server.cpu]:
   Options[server.cpu]: growright,nopercent
   Unscaled[server.cpu]: ymwd
   
   
   #
   # Memory Monitoring (Total Versus Available Memory)
   #
   
   Target[server.memory]: memAvailReal.0&memTotalReal.0:public@localhost
   Title[server.memory]: Free Memory
   PageTop[server.memory]: <h1>Free Memory</h1>
   MaxBytes[server.memory]: 100000000000
   ShortLegend[server.memory]: B
   YLegend[server.memory]: Bytes
   LegendI[server.memory]: Free
   LegendO[server.memory]: Total
   Legend1[server.memory]: Free memory, not including swap, in bytes
   Legend2[server.memory]: Total memory
   Options[server.memory]: gauge,growright,nopercent
   kMG[server.memory]: k,M,G,T,P,X
   
   
   #
   # Memory Monitoring (Percentage usage)
   #
   Title[server.mempercent]: Percentage Free Memory
   PageTop[server.mempercent]: <h1>Percentage Free Memory</h1>
   Target[server.mempercent]: ( memAvailReal.0&memAvailReal.0:public@localhost ) * 100 / ( memTotalReal.0&memTotalReal.0:public@localhost )
   options[server.mempercent]: growright,gauge,transparent,nopercent
   Unscaled[server.mempercent]: ymwd
   MaxBytes[server.mempercent]: 100
   YLegend[server.mempercent]: Memory %
   ShortLegend[server.mempercent]: Percent
   LegendI[server.mempercent]: Free
   LegendO[server.mempercent]: Free
   Legend1[server.mempercent]: Percentage Free Memory
   Legend2[server.mempercent]: Percentage Free Memory
   
   
   #
   # New TCP Connection Monitoring (per minute)
   #
   
   Target[server.newconns]: tcpPassiveOpens.0&tcpActiveOpens.0:public@localhost
   Title[server.newconns]: Newly Created TCP Connections
   PageTop[server.newconns]: <h1>New TCP Connections</h1>
   MaxBytes[server.newconns]: 10000000000
   ShortLegend[server.newconns]: c/s
   YLegend[server.newconns]: Conns / Min
   LegendI[server.newconns]: In
   LegendO[server.newconns]: Out
   Legend1[server.newconns]: New inbound connections
   Legend2[server.newconns]: New outbound connections
   Options[server.newconns]: growright,nopercent,perminute
   
   
   #
   # Established TCP Connections
   #
   
   Target[server.estabcons]: tcpCurrEstab.0&tcpCurrEstab.0:public@localhost
   Title[server.estabcons]: Currently Established TCP Connections
   PageTop[server.estabcons]: <h1>Established TCP Connections</h1>
   MaxBytes[server.estabcons]: 10000000000
   ShortLegend[server.estabcons]:
   YLegend[server.estabcons]: Connections
   LegendI[server.estabcons]: In
   LegendO[server.estabcons]:
   Legend1[server.estabcons]: Established connections
   Legend2[server.estabcons]:
   Options[server.estabcons]: growright,nopercent,gauge
   
   
   #
   # Disk Usage Monitoring
   #
   
   #Target[server.disk]: dskPercent.1&dskPercent.2:public@localhost
   #Title[server.disk]: Disk Partition Usage
   #PageTop[server.disk]: <h1>Disk Partition Usage /home and /var</h1>
   #MaxBytes[server.disk]: 100
   #ShortLegend[server.disk]: %
   #YLegend[server.disk]: Utilization
   #LegendI[server.disk]: /home
   #LegendO[server.disk]: /var
   #Options[server.disk]: gauge,growright,nopercent
   #Unscaled[server.disk]: ymwd
   

   Replace localhost with 'server IP' and 'public' with community name. Also change workdir appropriately.

2. Use command 'env LANG=C /usr/bin/mrtg /etc/mrtg/127.0.0.1-stats.cfg' to collect statictics. Same command with '--logging' option can be used in crontab.
3. Create index using 'indexmaker --output=/var/www/html/127.0.0.1-stats/index.html /etc/mrtg/mrtg.cfg /etc/mrtg/127.0.0.1-stats.cfg' command.

Note:

• This is not efficient way of using MRTG. We should use 'rrdtool' to optimize MRTG when used for monitoring large number of hosts.
• Steps on using 'rrdtool', monitoring disk partitions for free space and explanation of MRTG syntax are mentioned on link http://www.linuxhomenetworking.com/wiki/index.php/Quick_HOWTO_:_Ch23_:_Advanced_MRTG_for_Linux and still need to be learned.

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