[CentOS] Tool to Manage KVM with Web Browser

Hi All,

Is there someone out there using web browser to manage multiple KVM
host servers right now in checking the MIST.IO Cloud platform and there are
lot more from the http://linux-kvm.org/page/Management_Tools but Im not
sure what is the best for me. The first requirement is of-course it should
be open-source with zero cost and stable for daily operation. Anyone can
help me decide or advice the best web tools for KVM.

many thanks