LCOW

LCOW stands for Linux Containers on Windows, a method that allowed Linux-based container workloads to run on Windows hosts. It was introduced with Docker for Windows as a way to run Linux containers alongside Windows containers, without requiring separate Linux hosts.

Operation and architecture: LCOW uses Hyper-V to start a lightweight Linux virtual machine that runs a Linux kernel and userland. Inside this VM, the standard Linux container runtimes (such as containerd and runc) operate and host the Linux containers. The Windows Docker Engine communicates with the Linux VM to create, start, and manage Linux containers. Networking and storage are provisioned through the Hyper-V VM, with the Linux side handling Linux-specific behaviors while bridging to the Windows network when needed.

History and context: Announced in 2016–2017 as an experimental feature, LCOW required Hyper-V and a Windows edition that supports virtualization. It provided compatibility for Linux container images on Windows, but introduced performance and reliability considerations compared with native Windows containers. It remained an experimental option for some time and was gradually deprioritized as the ecosystem shifted toward newer approaches for Linux containers on Windows.

Decline and current status: By the late 2010s and into the 2020s, LCOW was deprecated in favor of a WSL 2–based backend, which uses the Windows Subsystem for Linux 2 to run a genuine Linux kernel and offers improved file system performance and compatibility. Modern Docker Desktop and Windows Server deployments typically rely on WSL 2 or Windows containers rather than LCOW, and LCOW is no longer recommended for new deployments.