I am using KVM on Ubuntu Server 12.04 and Virtual Machines are running on it in LVM. I want to migrate of them to Vmware-vsphere. How can I achieve this. Can some one suggest as where do I begin?
Ι don't think there is a direct qemu to vmware image converted. I think the best way to do it will be to treat the KVM VMs as if they were systems on bare metal.
Install vCenter Concerter on each of the VMs and run the program when the VM is turned on. Don't have it handy atm but one of the options should allow you to choose that the machine you are converting is the current live machine. Then import the created image to Vsphere.
I would use qemu-img for this. According to this List KVM as well as VMWare are supported. This will only convert your vdisks, but it's a way to start.