I want to setup a VM server and by my previous experience, the first thing that came to my mind was the "VMware ESXi" hypervisor. To use ESXi you need the client application, called "vSphere" to connect and manage your VMs remotely. Unfortunately vSphere is only published for Microsoft Windows and has no Linux version.
So my question is, what alternatives do I have instead of VMware ESXi that provides similar functionality and supports Linux? Are there any free/open-source hypervisors similar to ESX, where they have client applications for both Linux and Windows?
I've also heard from a few people that there is a product based on KVM by RedHat, but I don't have any info on it.