VMelike

VMElike refers to a class of execution environments that emulate the isolation and interface of a traditional virtual machine while emphasizing lower overhead and tighter integration with the host system. VMElike environments can run guest processes in an isolated address space and provide a defined set of system interfaces, often without requiring a full hardware virtual machine.

They achieve this through various approaches, including sandboxing using namespaces and seccomp on Linux, lightweight hypervisor layers, or WebAssembly-based runtimes. They typically intercept or route system calls, provide virtualized I/O, and enforce memory protection to prevent guest code from affecting the host. While not all VMElikes implement every feature of a conventional VM, they aim to offer familiar VM-like constructs such as process isolation, resource limits, and restartability.

Usage: They are used to safely run untrusted code, test software in isolated environments, or provide scalable, startup-fast environments for microservices and edge computing. They often trade some hardware-assisted VM capabilities for lower overhead, faster startup times, and better integration with container tooling.

Relation to other technologies: VMElike entities sit between containers and full VMs. They share containers' lightweight lifecycle and security models while offering stronger isolation, similar to VMs, but with potential limitations in device emulation or kernel-level features. Notable related efforts include sandboxing runtimes and WASM-based solutions, and several cloud vendors deploy VM-elike runtimes as part of their security sandboxes.

See also: virtualization, containerization, sandbox, WebAssembly, unikernel.