MRTG Config

[KOUMNI]

Hello,
I want to monitor my switch using MRTG, but something is not well configured, I followed some of the topics for the error that I have which is : "check_mrtgtraf: Unable to open MRTG log file "

knowing that /var/www/mrtg contains some interface logs
I read in some forums that /var/lib/mrtg/ must contain the log file that nagios reads, but in my case it contains only cfg files

can you guys help me through this config

[benjaminsmith]

Hello @koumni,

Have you checked permissions on that directory to make sure it is writable/accessible by the nagios account on the server? Please post the output to the following commands.

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ls -ld /var/lib/mrtg
ls -l /var/lib/mrtg

[cdienger]

I would also look at the /etc/mrtg/mrtg.cfg file which will have information about the log location and format.

[KOUMNI]

Hello @koumni,

Have you checked permissions on that directory to make sure it is writable/accessible by the nagios account on the server? Please post the output to the following commands.

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ls -ld /var/lib/mrtg
ls -l /var/lib/mrtg

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nagios@sn-srv-nagios:~$ ls -ld /var/lib/mrtg
drwxrwxrwx 2 nagios nagios 12288 Oct 27 15:04 /var/lib/mrtg

[KOUMNI]

I would also look at the /etc/mrtg/mrtg.cfg file which will have information about the log location and format.

Here it is

[tgriep]

Can you post the Nagios configuration you are using for the Port 1 Bandwidth Usage check?

Did you setup a cron job to run the MRTG application which gathers the Bandwidth information the check_mrtgtraf plugin needs to calculate the bandwidth?
Check this link for instructions for MRTG.
https://oss.oetiker.ch/mrtg/doc/mrtg-unix-guide.en.html

If you run the following as root, it will run the MRTG application in debug mode which you can use to troubleshoot the MRTG application.

[KOUMNI]

Can you post the Nagios configuration you are using for the Port 1 Bandwidth Usage check?

Did you setup a cron job to run the MRTG application which gathers the Bandwidth information the check_mrtgtraf plugin needs to calculate the bandwidth?
Check this link for instructions for MRTG.
https://oss.oetiker.ch/mrtg/doc/mrtg-unix-guide.en.html

If you run the following as root, it will run the MRTG application in debug mode which you can use to troubleshoot the MRTG application.

This is the service conf

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# Monitor bandwidth via MRTG logs

define service {

    use                     generic-service                     ; Inherit values from a template
    host_name               HP-DATA-CORE
    service_description     Port 1 Bandwidth Usage
    check_command           check_local_mrtgtraf!/var/lib/mrtg/172.20.232.1_1.log!AVG!1000000,1000000!5000000,5000000!10
}

this the command conf

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define command {

    command_name    check_local_mrtgtraf
    command_line    $USER1$/check_mrtgtraf -F $ARG1$ -a $ARG2$ -w $ARG3$ -c $ARG4$ -e $ARG5$
}

And this the crontab lines

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*/5 * * * * /usr/bin/env LANG=C /usr/bin/mrtg /etc/mrtg/mymrtg.cfg –logging /var/log/mrtg.log
*/5 * * * * /usr/bin/env LANG=C /usr/bin/mrtg /etc/httpd/conf/mrtg.cfg --logging /var/log/mrtg.log

[tgriep]

Your Nagios check is setup to use this file to gather the Bandwidth but is does not exist on your system.

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/var/lib/mrtg/172.20.232.1_1.log

The closest file I saw in the ls output is this named this.

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/var/lib/mrtg/172.20.232.1.log

Is this the MRTG log file you should be using for that check?

If not, you will have to re-run the cfgmaker command to create a new entry for that interface and then the plugin will find the file.
Else, edit the check and remove the _1 from the filename.