Page 269 - Cloud computing: From paradigm to operation

Framework and requirements for cloud computing 1

7.2 Virtual machine requirements

The virtual machine provides a virtualized and isolated computing environment for each guest operating
system (OS).

The virtual machine requirement includes:
• It is required to support migration of virtual machines between different physical computing
machines.
7.2.1 CPU virtualization
The central processing unit (CPU) virtualization allows running multiple virtual CPUs (vCPU) on a single
physical CPU.
The CPU virtualization requirement includes:

• The virtual machine's vCPUs' computing capability can optionally be specified as a fraction of a
physical CPU.

7.2.2 Memory virtualization
The memory virtualization includes memory allocation at the start of a virtual machine, memory utilization
monitoring during virtual machine operation and memory release at the shutdown of a virtual machine.
The memory virtualization requirement includes:
• It is recommended that while a virtual machine is active, the hypervisor monitors memory usage
and reallocates unused memory to other virtual machines dynamically.

7.2.3 Input/Output device virtualization
The Input/Output (I/O) virtualization allows division of the physical I/O device into several logical instances
for use by different virtual machines.
The I/O device virtualization requirements include:
• It is required for the hypervisor to support I/O virtualization capabilities.
• It is required that a virtual machine is capable of using virtual I/O devices abstracted from the
physical I/O devices.
• The number of virtual I/O devices is prohibited from being constrained by the number of physical
I/O devices.

• The data of one virtual machine transferred through a shared physical I/O device is prohibited from
being exposed to other virtual machines.
• Physical I/O devices can optionally be shared by multiple virtual machines.

7.2.4 Network interface virtualization
Network interface virtualization allows creating and deleting a virtual network interface for a guest virtual
machine OS regardless of the number of physical network interfaces.
The network interface virtualization requirements include:
• It is recommended that a physical network interface can be virtualized into multiple virtual network
interfaces.
• It is recommended that the virtual network interfaces from different virtual machines can be
grouped into one virtual local network.
7.2.5 Duplication of virtual machine

The duplication of a virtual machine allows creating new virtual machines and virtual machine backup in the
execution environment.

The duplication of a virtual machine requirement includes:
• A virtual machine can optionally be duplicated to create a new virtual machine with the same
configuration.

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