Archive for the ‘General’ Category

Nagios – Using NRPE

May 20th, 2012 Sanjib

In continuation to my previous post , I will now discuss how to use Third party Nagios plugins and how to make use of NRPE. Again, once you start to know how these things works, it will be a cake walk. Else you can get tangled up with all those configuration files.

You might need your Nagios to monitor a few applications or services, which plugins are not installed with the default Nagios plugins folder. So venture out for third party plugins, some of which are not so efficient and some good enough. You will find a few plugins which can start working with just a few steps. Download and put the plugin in your plugin folder ( generally /usr/local/nagios/libexec/ ) with 755 permission and ” nagios ” ownership , write proper code in the commands.cfg file and use it in your remotehost monitoring file ( e.g. apache1.cfg ) . (more…)

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Nagios – Installation Guide

May 13th, 2012 Sanjib

Nagios is an opensource monitoring tool which is used to monitor various kinds of hosts ( Windows and linux) and several kinds of services. Once you know how the Nagios works, its pretty easy to work with it although adding up new hosts or services is tedious job. Internet is full of comprehensive articles about Nagios installations. So I will try not to make this article repetitive of what is already available over the net, but try to explain a bit more on how the Nagios is actually working, so that you can understand what things to tweak and how, as per your requirement.

Installation if Nagios in brief.  There is already one autoinstaller available which you can use and get your Nagios installed without any effort. You can find the autoinstaller here. I have already used it and it works fine. However, you may need to make some changes in the Apache path , written in the script, only if you have installed Apache in a separate customized path or using other scripts like Bitnami Lampstack.

I would recommend you to install Nagios manually atleast once. You can find the steps in the following Pdf File. (more…)

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TCP/IP and UDP protocol

November 5th, 2011 Sanjib

Almost all the datas are transmitted using either the TCP/IP or UDP protocols. I will briefly discuss about the TCP/IP and UDP structures and the IP addressing system in this article.

Let’s first start with the IP address -  Each system in the internet ( or in private network) is recognised by an unique no.  and this no. stores important informations  about the network and the type of service. TCP/IP has three different levels of addressing :

  • Physical (Link) address – 6 bytes – This address determines the host system on a prticular network and can be either unicast(Single recipient) , Multicast(a group of recipients) or broadcast(received by all in network).** Not all networks support these, but Ethernet does.
  • Internetwork (IP) address – 4 bytes – This address can uniquely identify a host connected to the Internet. No two hosts in the Internet can have the same address. Internet address also supports unicast,multicast and broadcast addressing.
  • Transport or Port address – 2 bytes – The above two addressing system identifies the host but not the process to which the data actually corresponds to. For this a port address is used. e.g. Telnet uses port 23. (more…)
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Red Hat Cluster Suite

October 30th, 2011 Sanjib

In today’s world, every organisation in is thriving to provide a nonstop 24X7 service to their clients and so deploying high available solutions to their products. This is where a cluster concept kicks in. Along with some commercial high-availability solutions like IBM’s HACMP and Veritas’ Cluster Server and HP’s Serviceguard, Red Hat provides a high-availability solution on Red Hat Enterprise Linux, called the Red Hat Cluster Suite.

Red Hat Cluster Suite has two major features, the Cluster Manager ( Cman)  that provides high availability, and the IP load balancing (also called Piranha). The Cluster Manager and Piranha are complementary high-availability technologies and can be used in combination or separately, as per your requirements. (more…)

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Logical Volume manager (LVM)

October 29th, 2011 Sanjib

Using the Logical Volume Manager or LVM we can create special kind of volumes to store datas which can be increased or decreased as per need. This resizing of the volumes are of minimal effort and so comes handy for managing the resources effectively. The following diagram will give you a better understanding of how the LVM works

Let us consider there are two HDD of 10 GB each ( /dev/sda and /dev/sdb). We can create physical partitions of 5 GB in both the disks( /dev/sda1 , /dev/sda2, /dev/sdb1, /dev/sdb2). Now picking three of these partitions we create one volume group ( we can later include new hdd or the remaining 5 Gb partition to the volume group ) of 15 GB. Now we can create smaller logical volumes as per need from this available 15GB space. Lets consider we have created one logical volume of 8 Gb. So there is still 7 Gb of space in hold. We can use this space to make more Logical volumes of use it when the already created LV needs resizing. (more…)

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