Infi-Zeal's Blog

  This is the forth post in the cloud computing series, in this post we will be discussing further about cloud computing. The previous posts related to cloud computing are listed as follows: The power of cloud (Introduction to Cloud Computing) The architecture of cloud computing. Cloud computing Applications   Perhaps the biggest concerns about cloud computing are security and privacy . The idea of handing over important data to another company worries some people. Corporate executives might hesitate to take advantage of a cloud computing system because they can't keep their company's information under lock and key. The counterargument to this position is that the companies offering cloud computing services live and die by their reputations. It benefits these companies to have reliable security measures in place. Otherwise, the service would lose all its clients. It's in their interest to employ the most advanced techniques to protect their clients' d...

Nagios is an open source host, service and network monitoring program. An introductory post  to Nagios have has been published before. So lets continue that a with instructing the installation of Nagios on CentOS. Introduction This guide is intended to provide you with simple instructions on how to install Nagios from source (code) on CentOS and have it monitoring your local machine inside of 20 minutes. No advanced installation options are discussed here - just the basics that will work for 95% of users who want to get started. These instructions were written based on a standard CentOS 5.5 Linux distribution. What You'll End Up With If you follow these instructions, here's what you'll end up with: Nagios and the plugins will be installed underneath /usr/local/nagios Nagios will be configured to monitor a few aspects of your local system (CPU load, disk usage, etc.) The Nagios web interface will be accessible at http://localhost/nagios/ Prerequisites Du...

The applications of cloud computing are practically limitless. With the right middleware, a cloud computing system could execute all the programs a normal computer could run. Potentially, everything from generic word processing software to customized computer programs designed for a specific company could work on a cloud computing system. Why would anyone want to rely on another computer system to run programs and store data? Here are just a few reasons: Clients would be able to access their applications and data from anywhere at any time. They could access the cloud computing system using any computer linked to the Internet . Data wouldn't be confined to a hard drive on one user's computer or even a corporation's internal network. It could bring hardware costs down. Cloud computing systems would reduce the need for advanced hardware on the client side. You wouldn't need to buy the fastest computer with the most memory, because the cloud system would take...

When talking about a cloud computing system, it's helpful to divide it into two sections: the front end and the back end . They connect to each other through a network , usually the Internet . The front end is the side the computer user, or client, sees. The back end is the "cloud" section of the system. The front end includes the client's computer (or computer network) and the application required to access the cloud computing system. Not all cloud computing systems have the same user interface. Services like Web-based e-mail programs leverage existing Web browsers like Internet Explorer or Firefox . Other systems have unique applications that provide network access to clients. On the back end of the system are the various computers, servers and data storage systems that create the "cloud" of computing services. In theory, a cloud computing system could include practically any computer program you can imagine, from data processing to video ga...

Nagios Introduction Nagios is a free, open-source web-based network monitor developed by Ethan Galstad. Nagios is designed to run on Linux, but can be also be used on Unix variants. Nagios monitors the status of host systems and network services and notifies the user of problems. Nagios Functionality In common with many open source utilities, installation requires a degree of system administrator experience. Nagios is definitely not for the novice, unless you are prepared to put the effort in learning the basics. But with a wide range of features, including a number of web interfaces, Nagios is a very useful, feature rich monitoring tool. A large number of plug-ins available from the Nagios Library , means you can design its capabilities to your own requirements. Amongst others, Nagios monitors services such as SMTP, POP3, HTTP, PING and resources such as disk and memory usage, log files, processor load...

Let's say you're an executive at a large corporation. Your particular responsibilities include making sure that all of your employees have the right hardware and software they need to do their jobs. Buying computers for everyone isn't enough -- you also have to purchase software or software licenses to give employees the tools they require. Whenever you have a new hire, you have to buy more software or make sure your current software license allows another user. It's so stressful that you find it difficult to go to sleep on your huge pile of money every night. Soon, there may be an alternative for executives like you. Instead of installing a suite of software for each computer, you'd only have to load one application. That application would allow workers to log into a Web-based service which hosts all the programs the user would need for his or her job. Remote machines owned by another company would run everything from e-mail to word processing to ...

Zimbra combines email, calendar and address book tools in an integrated system . For the Web Client, this is all found at one address and under one login. Based on Postfix MTA, includes AJAX based web mail and calendering, antispan, search, backup, archiving, .... Built on top of Tomcat, MySQL, JAVA, Apache, Lucene, ClamAV, SpamAssassin, OpenLDAP and of course Postfix technologies. It rocks. I will use the hostname mail.rahlabs.com in this tutorial together with the IP address 192.168.0.110 . Adjust this to your needs, but make sure that mail.rahlabs.com has a valid MX record in DNS ( Zimbra needs this! ). I assume you want to create email accounts for rahlabs .com instead of mail.rahlabs.com , so you should have an MX record for rahlabs.com as well. In this example the Zimbra server is in a local network ( 192.168.0.110 is a private IP address) behind a router, so make sure you use the router's public IP address ( 1.2.3.4 in this example) in the DNS rec...