A little over a week ago, I received an email from a provider of virtual appliances for qemu/kvm and other hypervisors. It was only then that I realized that I didn’t really know of any other repository of virtual appliances for qemu/kvm so it was worth having a look. For those who’re not familiar with virtual appliances, the concept of the virtual appliance is very simple. They are basically virtual machines pre-configured with applications so as to ease the burden of deploying applications. The biggest beneficiary of this technology is the IT admin and, in fact, the concept isn’t new. Anyone in the IT field knows that the physical version of the appliance have been around for years now.

Getting the Virtual Appliance

The virtual appliances can be found here and are freely downloadable. All the appliances for qemu/kvm as well as other hypervisors are based on the ubuntu JeOS 8.04 otherwise known as “juice”. The JeOS from ubuntu is a mimimal linux distribution designed to minimize disk size and memory usage which make it ideal for deployment of virtual appliances. At the moment, the virtual appliances available at the site are LAMP stack, LAPP stack, Tomcat and Cacti. I decided to have a look at the Cacti virtual appliance.

The virtual appliances can be downloaded as either tar.gz, zip or tar.bz2 archives. I downloaded the cacti virtual appliance which was about 153 MB so download is easy unless you’re using a dialup connection. On expanding the archive you will see two files and a subdirectory similar to below.

[root@localhost cacti]# ls -la
total 40
drwxr-xr-x  3 root root  4096 2008-06-29 17:17 .
drwxr-xr-x 13 root root  4096 2008-06-23 00:27 ..
-rw-r--r--  1 root root 11416 2008-06-07 05:48 README.cacti.html
-rw-r--r--  1 root root  8648 2008-06-07 05:48 README.cacti.txt
drwxr-sr-x  2 root 1000  4096 2008-06-23 00:51 VA-Cacti

Within the directory containing the name of the appliance were three raw disk images each representing the parititions as you would probably have configured on a physical server; root, swap and data partitions.

-rw-r--r-- 1 root 1000 2147483648 2008-06-23 00:54 va-cacti-data.img
-rw-r--r-- 1 root 1000 1572864000 2008-06-23 00:54 va-cacti-root.img
-rw-r--r-- 1 root 1000  268435456 2008-06-07 05:42 va-cacti-swap.img

The virtual appliances for the qemu/kvm are in raw disk format so it expands to the maximum size when decompressed on disk as opposed to growable with the qcow virtual disk formats.

Booting the Virtual Appliance

To boot the virtual appliance I used the following command script.

/usr/local/kvm/bin/qemu-system-x86_64 \
-hda va-cacti-root.img \
-hdb va-cacti-data.img \
-hdc va-cacti-swap.img \
-m 400 \
-localtime \
-usb \
-usbdevice tablet &

The virtual appliance booted quickly without any hitches on a core 2 duo ,2.19 GHz host running Fedora 9. Below shows a snapshot during the boot sequence.

After booting the cacti appliance below shows the cpu and resource usage from within the idle guest which was minimal at 79MB RAM and very low cpu usage.

Conclusion

The availability of virtual appliances for any hypervisor can help to promote adoption. This is the first resource that I know of providing virtual appliances for qemu/kvm which is refreshing to see and good for the adoption of KVM being a recent hypervisor on the market. I think, though, that it is only a matter of time before we start seeing more virtual appliances from the community designed for qemu/kvm.

You can download these appliances at the following link

http://www.virtualappliances.net/