Nowadays, the use of clusters in research centers or industries is undeniable. Since few years, the usage of virtual machines (VM) offers more advanced resource management capabilities, using features such as virtual machine live migration. Because of the latest contributions in the domain, some may argue that single system image (SSI) technologies are now deprecated, without considering some complementarities between VMs and SSI technologies are possible. After evaluating different configurations, we show that combining both approaches allows us to better address cluster challenges such as flexibility for the usage of available resources and simplicity of use. In other terms, the study shows that VMs add a level of management flexibility between the hardware and the application, whereas, SSIs give an abstraction of the distributed resources. The simultaneous usage of both technologies could improve the overall platform resources utilization, the cluster productivity and the efficiency of the running applications.