Docker for Windows uses a Linux VM or WSL 2 to run containers because Windows lacks native Linux kernel features; 1) it automatically manages a lightweight Linux VM (or uses WSL 2) with Hyper-V to host the Docker daemon and containers; 2) the Docker CLI and Desktop interface forward commands to the daemon, enabling seamless interaction; 3) file sharing and port forwarding allow access to Windows files and localhost services; 4) it supports switching to Windows containers for .NET Framework or Windows-specific apps; 5) networking and file mounting are handled via virtual switches and the 9P protocol, making container management on Windows efficient and user-friendly.

Docker for Windows works by running containers on a lightweight Linux virtual machine (VM) that's managed automatically in the background, even though you're using a Windows operating system. Here's how it all fits together:

It uses a Linux VM under the hood

Even though you're on Windows, Docker relies on Linux kernel features like cgroups and namespaces to run containers. Since Windows doesn't natively support these, Docker for Windows sets up a small, hidden Linux VM using Hyper-V (Microsoft's virtualization technology).

• This VM runs a minimal Linux distribution (based on LinuxKit).
• It hosts the Docker daemon (dockerd) and runs your containers.
• The VM is managed automatically — you don’t have to set it up or maintain it manually.

You interact with Docker through the Docker CLI or Docker Desktop, which forwards commands to the daemon inside the VM.

Seamless integration with Windows

Despite the Linux backend, Docker for Windows feels native:

• Docker CLI works just like on Linux or macOS.
• Docker Desktop provides a GUI to manage containers, images, and settings.
• File sharing is set up so you can mount directories from Windows into Linux containers.
• Port forwarding lets you access services running in containers via localhost.

For example, if you run:

docker run -d -p 8080:80 nginx

You can immediately open http://localhost:8080 in your Windows browser.

Support for Windows containers (optional)

Docker for Windows can also run native Windows containers, which use the Windows kernel instead of Linux.

• You can switch between Linux and Windows containers in Docker Desktop (right-click the tray icon → "Switch to Windows containers").
• Windows containers require Windows 10 or Windows Server and use different base images (like mcr.microsoft.com/windows/servercore).
• They’re less common for general development but useful if you're building .NET Framework apps or need Windows-specific features.

Key components behind the scenes

• Hyper-V: Powers the virtualization. Required for Docker Desktop on Windows.
• WSL 2 (optional but recommended): Modern setups use WSL 2 (Windows Subsystem for Linux) as the backend instead of a full VM. It's faster and more integrated.
  • With WSL 2, Docker runs inside a WSL 2 Linux distribution, improving performance and file system access.
• Virtual Switch: Enables networking between containers, the host, and external networks.
• File sharing: Uses 9P or Plan 9 protocol to mount Windows directories into the Linux environment securely.

What happens when you run a container?

1. You type docker run ... in PowerShell or Command Prompt.
2. The Docker client sends the request to the Docker daemon running in the Linux VM (or WSL 2).
3. The daemon pulls the image (if needed) and starts a container using Linux kernel features.
4. Ports are mapped to your Windows host; volumes are mounted from your Windows file system.
5. You can access the app via localhost or manage it through Docker Desktop.

Basically, Docker for Windows bridges the gap between Windows and Linux container ecosystems. It handles the complexity of virtualization so you can focus on building and running apps. It’s not magic — it’s just smart use of VMs, WSL 2, and seamless integration.

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