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Wednesday, 23 November 2011

Implementing Advanced Server Monitoring

Implementing Advanced Server Monitoring

You now can combine all you have learned to create a configuration file that monitors all these variables, and then you can integrate it into the existing MRTG configuration.

A Complete Sample Configuration

Here is a sample configuration file that is used to query server localhost for CPU, memory, disk, and TCP connection information.

# 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/mrtg/

# CPU Monitoring
# (Scaled so that the sum of all three values doesn't exceed 100)

Target[server.cpu]:ssCpuRawUser.0&ssCpuRawUser.0:craz33guy@localhost + ssCpuRawSystem.0&ssCpuRawSystem.0:craz33guy@localhost + ssCpuRawNice.0&ssCpuRawNice.0:craz33guy@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
Options[server.cpu]: growright,nopercent
Unscaled[server.cpu]: ymwd

# Memory Monitoring (Total Versus Available Memory)

Target[server.memory]: memAvailReal.0&memTotalReal.0:craz33guy@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:craz33guy@localhost ) * 100 / ( memTotalReal.0&memTotalReal.0:craz33guy@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:craz33guy@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:craz33guy@localhost
Title[server.estabcons]: Currently Established TCP Connections
PageTop[server.estabcons]: < H1 >Established TCP Connections< /H1 >
MaxBytes[server.estabcons]: 10000000000
YLegend[server.estabcons]: Connections
LegendI[server.estabcons]: In
Legend1[server.estabcons]: Established connections
Options[server.estabcons]: growright,nopercent,gauge

# Disk Usage Monitoring

Target[server.disk]: dskPercent.1&dskPercent.2:craz33guy@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

Testing The Configuration

The next step is to test that MRTG can load the configuration file correctly.

Restart SNMP to make sure the disk monitoring commands in the snmpd.conf file are activated. Run the /usr/bin/mrtg command followed by the name of the configuration file three times. If all goes well, MRTG will complain only about the fact that certain database files don't exist. MRTG then creates the files. By the third run, all the files are created and MRTG should operate smoothly.

[root@bigboy tmp]# service snmpd restart
[root@bigboy tmp]# env LANG=C /usr/bin/mrtg /etc/mrtg/server-stats.cfg

Creating A New MRTG Index Page To Include This File

Use the indexmaker command and include your original MRTG configuration file from Chapter 22, "Monitoring Server Performance", (/etc/mrtg/mrtg.cfg) plus the new one you created (/etc/mrtg/server-stats.cfg).

[root@bigboy tmp]# indexmaker --output=/var/www/mrtg/index.html \
/etc/mrtg/mrtg.cfg /etc/mrtg/server-stats.cfg

Configuring cron To Use The New MRTG File

The final step is to make sure that MRTG is configured to poll your server every five minutes using this new configuration file. To do so, add this line to your /etc/cron.d/mrtg file.

0-59/5 * * * * root env LANG=C /usr/bin/mrtg /etc/mrtg/server-stats.cfg

Some versions of Linux require you to edit your /etc/crontab file instead. See Chapter 22, " Monitoring Server Performance", for more details. You will also have to restart cron with the service crond restart for it to read its new configuration file that tells it to additionally run MRTG every five minutes using the new MRTG configuration file.

[root@bigboy tmp]# service crond restart

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