We're currently running our infrastructure with XEN + CentOS and are thinking to make the move to Ubuntu (Both as Host and Guest) + KVM.
Our objective is to, at a later stage, create a private cloud using openstack/cloudstack however due to strict budgets we can't invest on the hardware needed to setup the cloud infrastructure alongside our current one. Since we have less than 10 Physical servers (yet with quite a few VM's) our idea was to migrate machines one by one from our current setup to the KVM+Ubuntu, my question here is the following, once we have the full kvm+Ubuntu infrastructure running, will we be able to "cloudify" it without having to rebuild all the machines (somehow import kvm guests to instances on openstack/cloudstack)? Or do we really need to build the cloud first?
Why the shift from CentOS to Ubuntu? Because aparently one needs to reinstall machines from scratch on major version upgrades (Say Centos 5 to 6), as you can imagine this is not ideal having to do every few years (specially when we will be scaling our infrastructure greatly in the future).
Both Dom0 and DomU's would be managed by puppet. Thanks for any suggestions