https://carmine.dev/posts/kubernetesclusterfcos/

clusterconfig.yml

apiVersion: kubeadm.k8s.io/v1beta3
kind: ClusterConfiguration
kubernetesVersion: v1.24.0
controllerManager:
  extraArgs: # specify a R/W directory for FlexVolumes (cluster won't work without this even though we use PVs)
    flex-volume-plugin-dir: "/etc/kubernetes/kubelet-plugins/volume/exec"
networking: # pod subnet definition
  podSubnet: 10.244.0.0/16
---
apiVersion: kubeadm.k8s.io/v1beta3
kind: InitConfiguration

fcos.bu.yml

variant: fcos
version: 1.4.0
storage:
  files:
    # CRI-O DNF module
    - path: /etc/dnf/modules.d/cri-o.module
      mode: 0644
      overwrite: true
      contents:
        inline: |
          [cri-o]
          name=cri-o
          stream=1.17
          profiles=
          state=enabled
    # YUM repository for kubeadm, kubelet and kubectl
    - path: /etc/yum.repos.d/kubernetes.repo
      mode: 0644
      overwrite: true
      contents:
        inline: |
          [kubernetes]
          name=Kubernetes
          baseurl=https://packages.cloud.google.com/yum/repos/kubernetes-el7-x86_64
          enabled=1
          gpgcheck=1
          repo_gpgcheck=1
          gpgkey=https://packages.cloud.google.com/yum/doc/yum-key.gpg
            https://packages.cloud.google.com/yum/doc/rpm-package-key.gpg
    # configuring automatic loading of br_netfilter on startup
    - path: /etc/modules-load.d/br_netfilter.conf
      mode: 0644
      overwrite: true
      contents:
        inline: br_netfilter
    # setting kernel parameters required by kubelet
    - path: /etc/sysctl.d/kubernetes.conf
      mode: 0644
      overwrite: true
      contents:
        inline: |
          net.bridge.bridge-nf-call-iptables=1
          net.ipv4.ip_forward=1
passwd: # setting login credentials
  users:
    - name: core
      ssh_authorized_keys:
        - <PASTE YOUR SSH PUBLIC KEY HERE>

start_fcos.sh

#!/bin/sh

IGN_CONFIG=<IGNITION FILE PATH>
IMAGE=<FEDORA COREOS QCOW2 IMAGE PATH>
VM_NAME=node$1
VCPUS=2
RAM_MB=4096
DISK_GB=10
STREAM=stable

chcon --verbose --type svirt_home_t ${IGN_CONFIG}
virt-install --connect="qemu:///system" --name="${VM_NAME}" \
    --vcpus="${VCPUS}" --memory="${RAM_MB}" \
    --os-variant="fedora-coreos-$STREAM" --import --graphics=none \
    --disk="size=${DISK_GB},backing_store=${IMAGE}" \
    --qemu-commandline="-fw_cfg name=opt/com.coreos/config,file=${IGN_CONFIG}"