Learn how VMs work and their role in providing isolated environments.
A Virtual Machine (VM) is a digital replica of a physical computer. It is a software-based computer that, like a physical one, runs an operating system and applications. The VM is completely isolated from the other VMs and the host machine itself. This isolation is a key benefit, ensuring that applications running on different VMs do not interfere with each other and that a crash in one VM does not affect the others. Each VM has its own virtual hardware, including a CPU, memory, hard drive, and network interface, which are all mapped to the real hardware of the physical host machine by the hypervisor. This setup allows multiple operating systems—even different ones like Windows and Linux—to run simultaneously on a single physical server. In the context of cloud computing, VMs are the foundational unit of IaaS (Infrastructure as a Service). Cloud providers manage massive fleets of physical servers running hypervisors, and when a customer requests a 'server' or 'instance', the provider's control plane carves out resources from the physical hardware pool to create and run a new VM for that customer. This enables the efficient sharing of physical infrastructure, leading to cost savings and the rapid provisioning of resources that characterize the cloud.