Running k0s worker nodes in Windows

Experimental status

Windows support feature is under active development and MUST BE considered as experemential.

Requirements

The cluster must have at least one worker node and control plane running on Linux. Windows can be used for running additional worker nodes.

Build

make clean k0s.exe

This should create k0s.exe with staged kubelet.exe and kube-proxy.exe

Description

the k0s.exe supervises kubelet.exe and kube-proxy.exe During the first run calico install script created as C:\bootstrap.ps1

The bootstrap script downloads the calico binaries, builds pause container and set ups vSwitch settings.

Running

It is expected to have docker EE installed on the windows node (we need it during the initial calico set up)

C:\>k0s.exe worker --cri-socket=docker:tcp://127.0.0.1:2375 --cidr-range=<cidr_range> --cluster-dns=<clusterdns> --api-server=<k0s api> <token>

Cluster control plane must be inited with proper config (see section below)

Configuration

Strict-affinity

To run windows node we need to have strict affinity enabled.

There is a configuration field spec.network.calico.withWindowsNodes, equals false by default. If set to the true, the additional calico related manifest /var/lib/k0s/manifests/calico/calico-IPAMConfig-ipamconfig.yaml would be created with the following values

---
apiVersion: crd.projectcalico.org/v1
kind: IPAMConfig
metadata:
  name: default
spec:
  strictAffinity: true

Another way is to use calicoctl manually:

calicoctl ipam configure --strictaffinity=true

Network connectivity in AWS

The network interface attached to your EC2 instance MUST have disabled “Change Source/Dest. Check” option. In AWS console option can be found on the Actions menu for a selected network interface.

Hacks

We need to figure out proper way to pass cluster settings from controller plane to worker.

While we don’t have it, there are CLI arguments: - cidr-range - cluster-dns - api-server

Some useful commands

Run pod with cmd.exe shell

kubectl run win --image=hello-world:nanoserver --command=true -i --attach=true -- cmd.exe

Manifest for pod with IIS web-server

apiVersion: v1
kind: Pod
metadata:
  name: iis
spec:
  containers:
  - name: iis
    image: mcr.microsoft.com/windows/servercore/iis
    imagePullPolicy: IfNotPresent