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Comment by djsumdog | Hacker News Reader

I hate how the Docker team called it native. Docker for Mac/Windows still run in a hypervisor because so much of Docker is specific to Linux/cgroups. There was a FreeBSD port of Docker that attempted to implement a lot of the Docker API using zfs+jails but it went unmaintained and was never ported to the newer modular Docker implementation.

You're always going to get that performance hit with the hypervisor layer there.

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> Docker for Mac/Windows still run in a hypervisor because so much of Docker is specific to Linux/cgroups.

As I understand it, that what you describe is true of Docker for Mac, but not Docker for Windows which uses Windows' built-in container support (analogous to cgroups).

https://stefanscherer.github.io/how-to-run-lightweight-windo...

As far as I understand it, that only applies to Windows-based containers running on Win 10 Pro/Enterprise or Win Server 2016.

This is true. Linux containers still require the VM running in Hyper-V in the background.

Docker for Windows is coming to use the WSL2, beta is already out.

Calling it “Docker for Windows” is still highly inappropriate and misleading. It is super confusing.

WSL 2 itself uses a hypervisor though, so this is sort of a moot point.

Is this correct? I thought the headline feature of WSL2 was that unlike WSL it didn't use the hypervisor.

Edit: I looked it up. WSL2 continues to use a VM.

https://devblogs.microsoft.com/commandline/announcing-wsl-2/

> Is this correct? I thought the headline feature of WSL2 was that unlike WSL it didn't use the hypervisor.

No, the headline feature of WSL2 is it uses a real Linux kernel under a hypervisor, as opposed to WSL1's approach of a kernel driver running inside the NT kernel which partially emulates the Linux syscall API.

> Edit: I looked it up. WSL2 continues to use a VM.

More accurately, WSL2 starts using a VM, whereas WSL1 didn't. WSL2 runs the Linux kernel inside a VM. WSL1 runs Linux processes under the NT kernel (albeit as a special type of lightweight process called a picoprocess), with an emulation layer to translate Linux syscalls into NT kernel calls.

You've got it backwards.

WSL was a translation layer between Linux and Windows, WSL2 uses Hyper-V (I believe with some special sauce to handle integration).

WSL2 doesn't continue to use a VM, it is new in that it uses a VM. WSL1 did not use a VM, it directly interfaced with the NT executive.

I preferred the old mac solution where they didn’t try to hide the vm from you. It was much more straightforward.

I personally disagree. I hated the whole docker-machine rubbish and exporting of the env vars.

That doesn't make the performance problems of docker-for-mac any less nasty though.

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