Hi :)
As far as I know, when you start/stop a VM (KVM or OpenVZ) prox is just starting the KVM/OpenVZ process.
E.g. /usr/bin/kvm -id 403 -chardev socket,id=qmp,path=/var/run/qemu-server/403.qmp,server,nowait -mon chardev=qmp,mode=control -vnc unix:/var/run/qemu-server/403.vnc,x509,password...