Suse Linux Tips: July 2010

Monday, July 26, 2010

SUSE LINUX ADMIN GUIDE (UXSUP)

SUSE LINUX ADMIN GUIDE

Tuesday, July 20, 2010

SUSE LINUX ADMINISTRATOR PRACTICE NOTES

Saturday, July 10, 2010

Suse Linux Online Help

Suse Linux Online Help for System Administration and Monitoring

iftop to monitor traffic/bandwidth in SUSE/openSUSE

iftop is yet another free opensource tool to measure bandwidth utilization on the network interfaces on your systems or servers. As the name predicts, iftop is what “top” utility is for CPU usage measurement.

iftop can also run in promiscous mode and listen for all traffic on the subnet and can also listen for traffic on specified networks. iftop can be run in custom modes like disabling DNS name lookups, converting ports to service names, displaying results in Bytes etc.

For a detailed list of options run iftop with a “-h” arguement as follows:

opensuse11:~ # iftop -h
iftop: display bandwidth usage on an interface by host

Synopsis: iftop -h | [-npbBP] [-i interface] [-f filter code] [-N net/mask]

-h display this message
-n don’t do hostname lookups
-N don’t convert port numbers to services
-p run in promiscuous mode (show traffic between other
hosts on the same network segment)
-b don’t display a bar graph of traffic
-B Display bandwidth in bytes
-i interface listen on named interface
-f filter code use filter code to select packets to count
(default: none, but only IP packets are counted)
-F net/mask show traffic flows in/out of network
-P show ports as well as hosts
-m limit sets the upper limit for the bandwidth scale
-c config file specifies an alternative configuration file

iftop, version 0.17
copyright (c) 2002 Paul Warren and contributors

Install IFTOP in openSUSE

Click from the 1-click installer for your openSUSE build to download the YMP file and launch an autmatic installation process which should add the required repositories and download and install the required packages and dependencies.

Once the installation finishes succesfully, iftop should be installed under /usr/sbin

opensuse11:~ # which iftop
/usr/sbin/iftop

To have a quick preview of the bandwidth utilization, simply run “iftop” without any arguements:

opensuse11:~ # iftop

iftop1
To run in a promiscous mode and listen for all traffic on the subnet, run with “-p” option

opensuse11:~ # iftop -p

iftop2
As shown earlier, use “-h” arguement for all options.

Click here to visit the project home.
Related posts

* 1-click installs for Nagios Addons & plugins in openSUSE 11.0 (3)
* 1-click installs for Nagios in openSUSE 11.1 (0)
* abby GUI & addons utilities for Clive/CClive (1)
* AbiWord – Free opensource Word Processor for openSUSE Linux (2)
* Acetoneiso2 – A full feature rich Image/ISO tool for openSUSE (6)

SUSE Linux Tips

Network Monitoring Through Nagios

Create an Admin user for nagios

opensuse11:~ # htpasswd2 -c /etc/nagios/htpasswd.users nagiosadmin

This creates a new htpasswd.user file (-c option) and installs nagiosadmin as a new user for nagios web interface. Any later user account should be added without the “-c” option as follows to avoid the risk of overwriting the htpasswd.users file

opensuse11:~ # htpasswd2 /etc/nagios/htpasswd.users nagiosuser

Thats the web interface sorted.

Make Nagios Start at system startup

Add Nagios to the list of services on the system and make it start automatically at the system start/restart as follows:

opensuse11:~ # chkconfig nagios

opensuse11:~ # chkconfig nagios on

We are nearly there to get Nagios up and running.

Restart Apache

Restart Apache2 webserver to enable the Nagios web interface

opensuse11:~ # rcapache2 restart

Start Nagios

The installation adds a configuration file for the localhost as /etc/nagios/objects/localhost.cfg. This checks the network status, system load, system users, HTTP, PING, Root partition, SSH, Swap and total processes running on the system. This gives us a quick look into Nagios before we go on and add additional systems and services.

opensuse11:~ # rcnagios start

Thats the installation complete. Open a web browser and browse to http://localhost/nagios or http:///nagios if browsing from another system on the network. (Make sure the firewall allows HTTP & HTTPS connections into this system). Enter the username and password for the admin user (nagiosadmin).

Thats it…Nagios is up and running. Now, you can add more devices like more Linux systems and servers, Windows or network appliances. Obviously,monitoring needs could change from anything being a dead or alive (ping) test to more checks like the ones we do here on the localhost.

A quick tip would be to create seperate config files for different types of devices like Windows, Linux etc or even a config file for each of the devices. This approach of config files for each device can reduce the maintenance perspective as you can pin point issues (if any) down to the particular file for the particular device also, any changes we know is for sure going to be only on the relevant file. The downside would be maintaing the files themselves.

Also, for each of these config files. there needs to be an entry in the /etc/nagios/nagios.cfg file. For instance, the localhost config file is entered as

cfg_file=/etc/nagios/objects/localhost.cfg

Else the cfg file will be completely ignored. Also, a good practice would be to verifiy the config changes (including adding or deleteing new devices) as failing to do so can bring down Nagios completely. To verify simply run nagios with “-v” switch and the config file as follows:

opensuse11:~ # nagios -v /etc/nagios/nagios.cfg

This should report any errors. When all looks good, restart nagios as follows

opensuse11:~ # rcnagios nagios restart

For more configuration details, click here to view Nagios Documentation

This entry was posted on Sunday, June 21st, 2009 at 10:26 pm and is filed under Monitoring. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.