Which technology typically provides security isolation in infrastructure as a service (IaaS) cloud computing?

In infrastructure as a service (IaaS) cloud computing, the technology that typically provides security isolation is virtual machines. Virtual machines (VMs) enable multiple instances of operating systems to run on a single physical server, each operating independently and isolated from one another. This isolation is achieved through hypervisor technology, which manages the VMs and ensures that processes and data from one VM are not accessible to another.

This isolation is crucial for security in a cloud environment, as it helps protect data and workloads from potential vulnerabilities and attacks that could arise from other tenants sharing the same physical hardware. The other options, while they have specific roles in cloud architecture, do not primarily focus on security isolation to the extent that virtual machines do.

For example, an application instance refers to the running application that may not have the isolation characteristics of VMs. A system image repository holds the images used to create VMs but does not provide real-time operational security. Operating systems run on the virtual machines but rely on the isolation provided by the VMs rather than providing isolation themselves. Thus, virtual machines play the key role in ensuring that resources are securely isolated in an IaaS environment.