7. Bare Metal Clouds

The unit of delivery for the usual IaaS is a virtual machine. This mode of delivery is appropriate when the goal is to carve out a nonfungible resource, namely a pool of servers possibly of different vintages and vendors with diverse forms of storage and heterogeneous network resources, into a normalized service offering: abstracted compute nodes with N processors, M gigabytes of memory, and C network interface controllers (NICs). To customers, the virtualized servers appear homogeneous even though the physical machines on which these nodes are deployed can be different and with varying configurations.