You can create an MSCS cluster with up to five nodes on a single ESXi host.

Note: Windows Server 2008 SP2 and above systems support up to five nodes (virtual machines). For supported guest operating systems see Other Clustering Requirements and Recommendations. Windows Server 2003 SP1 and SP2 systems support two nodes.

A cluster of virtual machines on one physical machine requires a host with one physical network adapter for the VMkernel. Use a separate physical network adapter for clustered virtual machines to connect with external hosts.