Virt

Virt, short for virtualization, refers to technologies that create virtual instances of computing resources such as CPUs, memory, storage, or entire machines. Virtualization enables multiple independent environments to run on a single physical host, improving utilization, flexibility, and isolation.

The central component is the hypervisor, which schedules and isolates virtual machines (VMs). Hypervisors come in two broad types: Type 1, which run directly on hardware (bare-metal), and Type 2, which run atop a host operating system. Hardware-assisted virtualization features, such as Intel VT-x and AMD-V, enhance performance and efficiency by enabling better separation between host and guest systems.

In addition to full virtualization, container-based approaches offer OS-level isolation without separate kernels. Containers, popularized by technologies like Docker and Kubernetes, are lighter-weight than VMs and share the host OS kernel, trading complete isolation for speed and density. Virtual machines provide stronger isolation at the cost of higher overhead, while containers excel in rapid deployment and scalability.

Common platforms and tools include KVM with QEMU (Linux), VMware ESXi, Microsoft Hyper-V, Xen, and Oracle VirtualBox. Libvirt provides a common management framework for many open-source backends, and Virt-manager offers a graphical interface for managing libvirt-based environments.

Applications of virtualization span server consolidation, development and testing, disaster recovery, training environments, and cloud services. It is foundational to modern data centers and many public cloud offerings, enabling flexible resource management, rapid provisioning, and scalable workloads. Considerations include performance overhead, security boundaries, licensing, and complexity of management.