Nagios allows you to graphically monitor your virtual servers from a single web page. No longer will you have to load each individual website or web service in order to verify consistent operation. Nagios can be downloaded directly from their website at:
http://www.nagios.com
On the Nagios homepage is a link to a 15 minute tutorial, which is relatively straight forward, and works like a charm. My next blog post will cover the same material that is included in their 15 minute tutorial. In this post I want to briefly discuss which guest operating system to use for maximum stability. I highly recommend Ubuntu JeOS for your virtual OS specifically because the kernel works flawlessly with the host operating system. To recap, I currently use Debian Etch as my host OS, and with JeOS as the guest the host CPU load is only active when the guest is actually processing data. I previously used Debian Etch also as the guest OS, and it would have a constant CPU load on the host. This was not at all desirable, and with a quick transition to JeOS the problem was swiftly resolved.
The first step to get Nagios up and running in a VirtualBox guest OS is to install a clean JeOS in a new guest OS.
Step 2 is setting up Nagios. You can follow the 15 minute tutorial on their website, which is indeed perfect, but I will also post the procedures asap.
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For the longest time I was using Debian for my guest operating system, and was relatively frustrated that the host OS always had a constant CPU load of over 20%. I tried many times to compile a custom kernel to resolve this issue, and in the end I decided to switch to a new OS. At first I though Ubuntu server edition was the way to go, but when I was installing the system there was all these gnome, and other graphical components being installed. What is the purpose of openoffice files in a terminal based OS? Overall Ubuntu JeOS is the way to go! It will only install the base Ubuntu system, comparable to how Debian can be configure during the installation process. The kernel used in JeOS does not cause the host to have a constant CPU load, therefore I am overwhelmingly satisfied with its performance.
If you are experiencing high host CPU load with your guest OS, I recommend experimenting with different kernels, and possible switching to a different OS if you cannot resolve the issue. There is no reason your host CPU load should be high when the guest is not processing any data. JeOS is the way to go 
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Since the transition to my new server I have yet to copy over the old .vdi files from the original machine. Truthfully they have to be redone, and copied properly using the clonevdi option part of VBoxManage. This is the only way to preserve the integrity of a .vdi. I have copied over two small vdi images including Ubuntu JeOS Gutsy, and Debian LAMP; they are available in the high speed downloads section of VirtLinux.com. Note that they were copied using traditional methods, and may not be fully functional.
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I have upgrade VirtLinux.com with clean XHTML compliant code. I have only done the homepage, and will finish the other pages by the end of the week. Since this is a new service, and one that could catch on quick I wanted to provide the best website coding possible in an effort to maximize bandwidth potential. I am happy to release the new High Speed downloads page, which will offer up to 1MB/s download speeds. Currently the high speed downloads are limited to approximately 500 per month; I will increase this if the site picks up in popularity. Ubuntu JeOS currently has 26 minutes remaining as I write this post; it is being uploaded to my hosted server It will automatically become available at approximately 5:45 PM EST.
http://www.virtlinux.com
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In an effort to provide better download speeds, I have uploaded a JeOS Gutsy VirtualBox VDI image to my hosted domain that has much better bandwidth than my home servers. The hosted domain will provide upwards of 1Mb/s which is about 20 times faster than the regular downloads. I will continue to host all the original downloads, although they will remain limited in bandwidth. The new high speed VDI downloads will be available on VirtLinux on the High Speed page. VirtLinux will be down until later today. Today is 11/22/2007 3:39PM EST.
http://www.virtlinux.com
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Je = Just enough. This distribution is a minimal installation specifically tailored to the VMWare software package. By providing just enough OS power to get VMWare running, a computer with JeOS will eliminate all wasted space associated with a Desktop installation that is not needed for a Virtual Server environment.
With a reasonably powerful computer, JeOS, and VMWare you will be able to deploy multiple Virtual machines on a single host allowing for easy backup of different server components. The main benefit of a Virtual Guest OS is its one file storage method; a quick drag and drop to a usb Hard Drive and a backup is quickly achieved.
Launchpad is the home for JeOS developments, therefore for updates and news check there:
https://launchpad.net/ubuntu-jeos/
For the most recent Ubuntu JeOS image check out the repos:
http://cdimage.ubuntu.com/jeos/releases/gutsy/release/
I have added a JeOS VirtualBox VDI image to VirtLinux.com. It is available on the high speed downloads page.
http://www.virtlinux.com
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