Create a Kubernetes cluster based on Rancher's k3s project with distinct hosts for the control plane and worker nodes on a bare metal machine running Linux and libvirt + qemu/kvm.

• A bare metal machine with
  • at least 16GB memory (for 1 master, 2 worker nodes), 32GB recommended)
  • a CPU with at least 4 physical cores
  • with any Linux distro (this guide assumes Ubuntu 18.04)
• Install libvirt, qemu/kvm. E.g., on Ubuntu:

  apt-get install -qy qemu-kvm libvirt-bin virtinst python3 vagrant

• Start the libvirt daemon. Using either virsh or virt-manager, create a virtual network:

  virsh -c qemu:///system net-create libvirt/default_network.xml

• Install the vagrant-libvirt plugin:

  vagrant plugin install vagrant-libvirt

• Initialize and install the virtualenv:

  python -m venv venv
  pip install -r requirements.txt

./generate_inventory_local.sh

ansible-playbook -i hosts_vagrant.ini create-k3s-cluster.yml

• Install kubectl on the local machine
• Configure it

  mkdir -p ~/.kube && vagrant ssh master01 -c 'sudo cat .kube/config' > ~/.kube/config

• Run kubectl

  # kubectl cluster-info
  Kubernetes master is running at https://192.168.122.127:6443
  CoreDNS is running at https://192.168.122.127:6443/api/v1/namespaces/kube-system/services/kube-dns:dns/proxy
  Metrics-server is running at https://192.168.122.127:6443/api/v1/namespaces/kube-system/services/https:metrics-server:/proxy
  
  To further debug and diagnose cluster problems, use 'kubectl cluster-info dump'.
  
  # kubectl get nodes
  NAME       STATUS   ROLES    AGE    VERSION
  master     Ready    master   149m   v1.19.3+k3s2
  worker-3   Ready    <none>   139m   v1.19.3+k3s2
  worker-2   Ready    <none>   139m   v1.19.3+k3s2
  worker-1   Ready    <none>   139m   v1.19.3+k3s2