Before I continue with the blog series about the open source data center, I would like to take opportunity to summarize what happened so far:

The hardware is installed, the first system is half done. Now there should be the part where some virtual machines are pushed to the box controlling the infrastructure and the services.

So far so good, but before I describe this, I would like to talk a bit about developing and testing. Setting up complex scenarios like virtual data centers, even based on infrastructure as code, demands on testing the procedures before deploying it into production. This requires the possibility to reproduce the real setup in a virtual way. I start working with Vagrant http://www.vagrantup.com/ to test my Puppet modules. Vagrant use VirtualBox to create virtual machines based on a definition file. You can find some examples here. The main problem with Vagrant is, you need quite powerful hardware to use it in scenarios with more than one vm.

More a bit by accident I saw a video on the Puppetlabs channel where Tomas Doran talks about Docker. Docker is somehow a lightweight version of Vagrant using Linux containers instead of full vms. This restrict the use case to Linux testing but gives you the ability to do this much faster (start a container in less than 5 seconds) and do this with much more complexity on ordinary hardware. I’ll shared a beta of my three Docker scenarios (scientific, centos and fedora) on my github account here. Feel free to extend the examples and push merge requests on github.

Back to the open source data center, I currently think about changing the strategy a bit and use techniques like Docker for demonstration. So it could be, that it take some time before I continue with this blog series, depending on the procedure I’ll use to show the further steps.