Virtualisation
Virtualisation provides software with a simulated environment. For servers, a hypervisor allocates physical resources to separate virtual machines.
What does virtualisation mean?
Virtualisation simulates a software or hardware environment on which other software runs. Here the focus is server virtualisation: several virtual machines use the resources of a physical computer. NIST describes the hypervisor as the layer between guest systems and hardware. It manages access to computing power, memory, disks and network interfaces.
Each of these virtual machines can run its own guest operating system and applications. This separates environments logically while they continue sharing physical resources. Application and operating-system virtualisation are other forms; they are not treated here as equivalent to a full server VM.
Two environments on one physical host
In the fictional example, test system VM-A and production system VM-B run on shared computer HOST-8. They have separate guest operating systems and allocated resources. The test system should have no permission to access production data; that boundary must be configured and checked.
Failure of the shared host can affect both machines. Overload and shared storage must also be considered in planning. Dividing resources alone does not create independent failure domains.
The company’s decision therefore involves more than the possible number of VMs: who manages the hypervisor, guest systems and their access? What capacity remains during failures, and how will operations recover? Agree on the necessary boundaries and evidence before consolidating systems.
Sources
Related terms
- Virtual machineA server VM runs a guest operating system. The operating model must clarify who handles the application, access and maintenance.
- Cloud computingCloud computing provides IT resources over a network on demand. Service and deployment models determine which tasks remain with the company.
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- Envelope-FromEnvelope-From identifies the SMTP sender for transport and error feedback. It must be distinguished from the visible sender address.
- DMARC aggregate reportA DMARC aggregate report summarises a reporting mail system’s domain checks over a period. It helps examine sending sources and misconfigurations.
- DMARC policyA DMARC policy describes the requested handling of failed domain checks. It repairs neither sending sources nor their alignment.
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