Swarm is known to work acceptably on VMware ESXi, VMware Workstation on PC, and VMware Fusion on Mac provided the application does not update objects more frequently than once per minute. VMware is currently the only virtualization platform under which Swarm is officially tested.
Swarm is known to have failures running on VirtualBox due to a bug associated with its embedded Debian kernel. Some clients have reported networking problems using KVM which appear to be multicast related.
In general, whether with virtual or real hardware, if infrastructure components outside of Swarm's control, such as network devices, are not correctly performing their intended function, you will need to be in a position to diagnose these alone or with support from the component's vendor.
UEFI booting is not supported on VMs due to the bug [SWAR-8054].