VM template assembly details: Step 6/7 - Convert and compress the VM
By Gabor Puhalla on Dec 17, 2009
Convert your master template to desired virtualization formats, compress it and you are done!
This is the last entry in a series that's objective is to share our experience with building VM templates. Rather then describing a general approach or process, we are sharing our experience through the specific example of building the Sun Glassfish Web Space Server 10 VM Template that we announced in June this year.
You may want to release your VM Template in various virtualization formats. There are many conversion tools out on the market that support the conversion of a VM image in a given format to other formats. Here is a couple of examples of those that we used while creating the Web Space Server 10 VM Template:
You might not get tools for each virtualization platform that you may want to support. In those cases you may need to create your template on the given platform from scratch or use other OS level techniques to clone the image.
You will want to compress your VM Template once you are done, primarily because it improves the download experience. The two primary formats that we used to provide the Web Space Server 10 VM Template: zip and 7zip. zip is a well established, wide spread format and hence decompression should be straightforward for most of your users. The main advantage of 7zip is that it is highly efficient. The resulting compression saved tens of MB compared to zip. 7zip conversion tools are available for most of OS platforms today and your users should have no problems decompressing the image, although in some cases they may need to download the tool from the net to be able to do the decompression. See examples of different compression results for different compression tools on Rudolf Kutina's blog.
Publishing this last step of the series took more time than what I originally anticipated. I hope, however, that you enjoyed the reading and that you will be able to reuse some of the principals of the process published in your practice.