[libvirt] networking with two hosts

The following situation is given: Host A with VM1 and VM2 running. Host B with VM3 und VM4 running. Task 1.) Each VM must have network access to each other VM and to the outside. Task 2.) When one host fails, all VMs are running on the remainig host and 1.) must still be fulfilled. Does somebody has any hints about realising this scenario with libvirt and KVM? mfg ar -- Hier könnte keine Signatur stehen.