Using WSL2 🔗︎

Kind can run using Windows Subsystem for Linux 2 (WSL2) on Windows 10 Insider builds. All the tools needed to build or run kind work in WSL2, but some extra steps are needed to switch to WSL2. This page covers these steps in brief but also links to the official documentation if you would like more details.

Getting Windows 10 Insider Preview 🔗︎

Download latest ISO at https://www.microsoft.com/en-us/software-download/windowsinsiderpreviewadvanced . Choose “Windows 10 Insider Preview (FAST) - Build 18990”. If there’s a later build, that will work too.

Installing on a virtual machine 🔗︎

Note: this currently only works with Intel processors. The Hyper-V hypervisor used by WSL2 cannot run underneath another hypervisor on AMD processors.

Required Settings

Now, start up the VM. Watch carefully for the “Press any key to continue installation…” screen so you don’t miss it. Windows Setup will start automatically.

Installing on a physical machine 🔗︎

If you’re using a physical machine, you can mount the ISO, copy the files to a FAT32 formatted USB disk, and boot from that instead. Be sure the machine is configured to boot using UEFI (not legacy BIOS), and has Intel VT or AMD-V enabled for the hypervisor.

Tips during setup 🔗︎

Setting up WSL2 🔗︎

If you want the full details, see the Installation Instructions for WSL2. This is the TL;DR version.

Once your Windows Insider machine is ready, you need to do a few more steps to set up WSL2

  1. Open a PowerShell window as an admin, then run

    Enable-WindowsOptionalFeature -Online -FeatureName VirtualMachinePlatform, Microsoft-Windows-Subsystem-Linux
  2. Reboot when prompted.

  3. After the reboot, set WSL to default to WSL2. Open an admin PowerShell window and run wsl --set-default-version 2.

  4. Now, you can install your Linux distro of choice by searching the Windows Store. If you don’t want to use the Windows Store, then follow the steps in the WSL docs for manual install.

  5. Start up your distro with the shortcut added to the start menu

  6. If you’re on build 18941 (July 19, 2019) or earlier, then you’ll need to build and update the kernel. See Updating Kernel. Otherwise, move on to the next section.

Setting up Docker in WSL2 🔗︎

  1. Install Docker - here’s links for Debian, Fedora, and Ubuntu
  2. Start the Docker daemon using init (not systemd) sudo service docker start. This needs to be done each time you start WSL2.

Now, move on to the Quick Start to set up your cluster with kind.

Troubleshooting 🔗︎

Failures with kind cluster create 🔗︎

Cannot find cgroup mount destination: unknown 🔗︎

If you close the WSL window and reopen it, the WSL cgroups can get into a bad state like this:

$ kind create cluster
Creating cluster "kind" ...
 ✓ Ensuring node image (kindest/node:v1.15.3) 🖼
ERRO[11:23:00] 4e74382817ac26772d90c3d78fc79b0102d5a6466640afb87482acf689394bac
ERRO[11:23:00] docker: Error response from daemon: cgroups: cannot find cgroup mount destination: unknown.
 ✗ Preparing nodes 📦
ERRO[11:23:00] docker run error: exit status 125
Error: failed to create cluster: docker run error: exit status 125

The workaround for this it to:

  1. Close all WSL windows
  2. In an admin PowerShell window run wsl.exe --shutdown
  3. Open a new WSL window, and run sudo service docker start

Now kind will be able to create clusters again normally.

This bug is tracked in WSL#4189.

Failed to list nodes: exit status 1 🔗︎

kind create cluster will fail right after starting WSL since systemd, and therefore the dockerd unit, is not automatically started.

$ kind create cluster
Error: could not list clusters: failed to list nodes: exit status 1

To fix this, run sudo service docker start, then try again.

This bug is tracked in WSL#994.

Helpful Tips for WSL2 🔗︎

Updating Kernel 🔗︎

In Windows 10 Insider build 18941 and earlier, the WSL2 kernel is still missing a few features needed for kind to work correctly. A custom kernel is needed. Since WSL2 is installed and working, it’s easy to build a new one with the right features included. Builds after that don’t need any kernel changes.

For the latest status on this, see issue #707 and microsoft/wsl#4165.

First, clone the latest WSL2-Linux-Kernel source and build it.

# This assumes Ubuntu or Debian, a different step may be needed for RPM based distributions
sudo apt install build-essential flex bison libssl-dev libelf-dev
git clone --depth 1 https://github.com/microsoft/WSL2-Linux-Kernel.git
cd WSL2-Linux-Kernel
make -j4 KCONFIG_CONFIG=Microsoft/config-wsl
mkdir /mnt/c/linuxtemp
cp arch/x86_x64/boot/bzImage /mnt/c/linuxtemp/

Now, open an administrator PowerShell window and run these steps to apply the kernel:

wsl.exe --shutdown
cd C:\WINDOWS\system32\lxss\tools
$acl = Get-Acl .\kernel
$acl.AddAccessRule( ( New-Object System.Security.AccessControl.FileSystemAccessRule(".\Administrators","FullControl","Allow") ) )
$acl | Set-Acl .\kernel
Move-Item kernel kernel.orig
Copy-Item c:\linuxtemp\bzImage kernel