Some courses and theses are done in virtualized environments, such as the VMware vSphere Hypervisor (ESXi). Laboratory virtualization guide includes some common help and guidelines for using such environments and working with them.
If you bring us virtual machines for use in labs or the vCloud Director environment, the images should be VMware vSphere 5.0 compatible (VM version 8) and in OVF/OVA format as plain VMX/VMDK images can be troublesome. If using software other than VMware to create the images, please remove USB/Audio devices and use SCSI disks instead of SATA/IDE. More information about format conversion in the guide above.