microVM

MicroVMs are a class of virtualization technology designed to provide strong isolation for workloads with the fast startup and low overhead often associated with containers. They run a lightweight virtual machine using hardware-assisted virtualization, typically through a small virtual machine monitor. The guest can be a trimmed Linux kernel, a minimal operating system, or a specialized unikernel, depending on the workload and orchestration needs.

Architecturally, a microVM includes a minimal VMM that presents a restricted set of virtual devices to the guest. Common I/O paths use paravirtualized interfaces such as virtio for network and block devices, which helps reduce overhead. The goal is to maintain the security guarantees of hardware virtualization while keeping the boot time short and the memory footprint modest. MicroVMs are designed to be ephemeral and easily instantiated, paused, or destroyed as workloads demand.

In practice, microVMs offer stronger isolation than traditional containers due to hardware-assisted virtualization, yet they aim to boot faster and consume fewer resources than full-featured VMs. They are well suited to multi-tenant environments, serverless and function-as-a-service platforms, edge computing, and other scenarios where rapid scaling and security isolation are important. Trade-offs include greater complexity in management and tooling compared to containers, and typically higher per-instance overhead than containers, though still lower than many conventional VMs.

Prominent examples include Firecracker, an open-source microVM implementation from AWS, which inspired further projects such as Kata Containers that blend VM isolation with container workflows. Several cloud providers and virtualization vendors have explored microVM designs to balance security, performance, and operational simplicity.