Linux Admin Zone

ntop is one of the most powerful and easy to use tool for network traffic statistics viewing and analysis.

Here are quick steps to install it on CentOS 5.2 box (upgraded from 5.0 release).

Try to install in easy way:
# yum install ntop

Most probably yum get failed for missing dependencies such as rrdtool package. If this is the case, download and install this package manually:

# cd /usr/src
# wget http://dag.wieers.com/rpm/packages/rrdtool/rrdtool-1.2.23-1.el5.rf.i386.rpm
# rpm -ivh rrdtool-1.2.23-1.el5.rf.i386.rpm --nodeps

I’ve used –nodeps option in rpm command to ignore any dependencies. Yum will take care of that, we just need rrdtool as of now.

One of my colleage performed speedy installation of NRPE module in a machine but found that the Nagios server is not able to query that machine.

In Nagios screen it shows:
NRPE: Unable to read output.

Checking from the machine itself, NRPE is giving correct version but throwing same error for any other checks:
[root@domU:/usr/local/nagios/libexec] ./check_nrpe -H localhost
NRPE v2.8

[root@domU:/usr/local/nagios/libexec] ./check_nrpe -H localhost -c check_load
NRPE: Unable to read output

After further digging, I’ve found he installed Nagios-plugins using yum which placed plugins files in some different location then desired by NRPE.

Munin is an efficient and lightweight Monitoring tool. Its available in ‘server’ and ‘node’ packages. You can install server in a single machine and node in all other machines and then view all information/statistical data in server machine.

This quick copy and paste howto explains steps needed to setup server and multiple nodes. These steps are tested in CentOS 5 Server but I do not issue any guarantee that this will work for you.

Step 1. Prepare Server machine. For quick installation and dependency resolution, you can install DAG repository:
# rpm -Uhv http://apt.sw.be/packages/rpmforge-release/rpmforge-release-0.3.6-1.el4.rf.i386.rpm