Using WSL2
Kind can run using Windows Subsystem for Linux 2 (WSL2) on Windows 10 May 2020 Update (build 19041).
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
Download latest ISO at https://www.microsoft.com/en-us/software-download/windows10ISO. Choose “Windows 10 May 2020 Update”. If there’s a later update, 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
- At least 8GB of memory
- It’s best to use a static memory allocation, not dynamic. The VM will automatically use paging inside so you don’t want it to page on the VM host.
- Enable nested virtualization support. On Hyper-V, you need to run this from an admin PowerShell prompt -
Set-VMProcessor -VMName ... -ExposeVirtualizationExtensions $true
- Attach the ISO to a virtual DVD drive
- Create a virtual disk with at least 80GB of space
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
- You can skip the product key page
- On the “Sign in with Microsoft” screen, look for the “offline account” button.
Setting up WSL2
If you want the full details, see the Installation Instructions for WSL2. This is the TL;DR version.
Once your Windows machine is ready, you need to do a few more steps to set up WSL2
Open a PowerShell window as an admin, then run
Enable-WindowsOptionalFeature -Online -FeatureName VirtualMachinePlatform, Microsoft-Windows-Subsystem-Linux
Reboot when prompted.
After the reboot, set WSL to default to WSL2. Open an admin PowerShell window and run
wsl --set-default-version 2
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.
Start up your distro with the shortcut added to the start menu
Setting up Docker in WSL2
Install Docker with WSL2 backend here: https://docs.docker.com/docker-for-windows/wsl/
Now, move on to the Quick Start to set up your cluster with kind.
Accessing a Kubernetes Service running in WSL2
prepare cluster config with exported node port
# cluster-config.yml
kind: Cluster
apiVersion: kind.x-k8s.io/v1alpha4
nodes:
- role: control-plane
extraPortMappings:
- containerPort: 30000
hostPort: 30000
protocol: TCP
create cluster
kind create cluster --config=cluster-config.yml
create deployment
kubectl create deployment nginx --image=nginx --port=80
create service
kubectl create service nodeport nginx --tcp=80:80 --node-port=30000
access service
curl localhost:30000
Kubernetes Service with Session Affinity
If you want to create a Kubernetes Service with sessionAffinity: ClientIP
it will not be accessible (and neither will any Service created afterwards). WSL2 kernel is missing xt_recent
kernel module, which is used by Kube Proxy to implement session affinity. You need to compile a custom kernel to enable this feature.
Build a kernel with
xt_recent
kernel module enableddocker run --name wsl-kernel-builder --rm -it ubuntu:latest bash
WSL_COMMIT_REF=linux-msft-5.4.72 # change this line to the version you want to build
# Install dependencies
apt update
apt install -y git build-essential flex bison libssl-dev libelf-dev bc
# Checkout WSL2 Kernel repo
mkdir src
cd src
git init
git remote add origin https://github.com/microsoft/WSL2-Linux-Kernel.git
git config --local gc.auto 0
git -c protocol.version=2 fetch --no-tags --prune --progress --no-recurse-submodules --depth=1 origin +${WSL_COMMIT_REF}:refs/remotes/origin/build/linux-msft-wsl-5.4.y
git checkout --progress --force -B build/linux-msft-wsl-5.4.y refs/remotes/origin/build/linux-msft-wsl-5.4.y
# Enable xt_recent kernel module
sed -i 's/# CONFIG_NETFILTER_XT_MATCH_RECENT is not set/CONFIG_NETFILTER_XT_MATCH_RECENT=y/' Microsoft/config-wsl
# Compile the kernel
make -j2 KCONFIG_CONFIG=Microsoft/config-wsl
# From the host terminal copy the newly built kernel
docker cp wsl-kernel-builder:/src/arch/x86/boot/bzImage .
Configure WSL to use newly built kernel: https://docs.microsoft.com/en-us/windows/wsl/wsl-config#configure-global-options-with-wslconfig
Create a
.wslconfig
file inC:\Users\<your-user-name>\
:[wsl2]
kernel=c:\\path\\to\\your\\kernel\\bzImage
Helpful Tips for WSL2
- If you want to terminate the WSL2 instance to save memory or “reboot”, open an admin PowerShell prompt and run
wsl --terminate <distro>
. Closing a WSL2 window doesn’t shut it down automatically. - You can check the status of all installed distros with
wsl --list --verbose
. - If you had a distro installed with WSL1, you can convert it to WSL2 with
wsl --set-version <distro> 2