Sometimes I need to setup a small kube cluster without thinking about it...

Vagrantfile

Vagrant.configure(2) do |config|
  CNI_LOOPBACK = <<-EOF
  {
      "cniVersion": "0.3.0",
      "type": "loopback"
  }
  EOF



  nodes = []
  Node = Struct.new(:ip, :subnet, :pod_cidr)
  (1...4).each do |i|
    nodes[i] = Node.new("10.100.0.11#{i}", "255.255.0.0", "10.200.#{i}.0/24")
  end
  (1...4).each do |i|
    node_info = nodes[i]
    cni_bridge = <<-EOF
    {
        "cniVersion": "0.3.0",
        "name": "bridge",
        "type": "bridge",
        "bridge": "cnio0",
        "isGateway": true,
        "ipMasq": true,
        "ipam": {
            "type": "host-local",
            "ranges": [
              [{"subnet": "#{node_info.pod_cidr}"}]
            ],
            "routes": [{"dst": "0.0.0.0/0"}]
        }
    }
    EOF
    config.vm.define "kube-#{i}" do |config|
      config.vbguest.auto_update = true
      config.vm.box = "ubuntu/xenial64"
      config.vm.network "private_network", ip: node_info.ip, netmask: node_info.subnet
      config.vm.hostname = "kube-#{i}"

      config.vm.provision "shell", inline: "sudo sed -i 's/127\.0\.0\.1\s*kube-#{i}.*/#{node_info.ip} kube-#{i}/' /etc/hosts"
      (1...4).each do |j|
        if i == j
          next
        end
        other = nodes[j]
        config.vm.provision "shell", inline: "grep kube-#{j} /etc/hosts && exit 0; sudo echo #{other.ip} kube-#{j} >> /etc/hosts"
        config.vm.provision "shell", inline: "ip route | grep #{other.pod_cidr} && exit 0; ip route add #{other.pod_cidr} via #{other.ip}"
      end

      config.vm.provision "shell", inline: "which dockerd && exit 0; sudo curl https://get.docker.com | sh && sudo usermod -G docker ubuntu"
      config.vm.provision "shell", inline: <<-eos
        which kubeadm && exit 0

        sudo apt-get update && apt-get install -y curl apt-transport-https inotify-tools
        curl -s https://packages.cloud.google.com/apt/doc/apt-key.gpg | sudo apt-key add -
        sudo echo "deb http://apt.kubernetes.io/ kubernetes-xenial main" > /etc/apt/sources.list.d/kubernetes.list
        sudo apt-get update && sudo apt-get install -y kubelet kubeadm kubectl
      eos

      unless Dir.exists?("./net.d.#{i}")
        Dir.mkdir("./net.d.#{i}")
      end
      f = File.new("./net.d.#{i}/99-loopback.conf", "w+")
      f.write(CNI_LOOPBACK)
      f.close()

      f = File.new("./net.d.#{i}/10-bridge.conf", "w+")
      f.write(cni_bridge)
      f.close()

      config.vm.synced_folder "./net.d.#{i}", "/etc/cni/net.d"
      config.vm.provision "shell", inline: <<-eos
        [ -d /opt/cni/bin ] && exit 0

        echo Downloading CNI plugins
        sudo /opt/cni/bin
        curl -sSLf https://github.com/containernetworking/plugins/releases/download/v0.6.0/cni-plugins-amd64-v0.6.0.tgz | tar -zx -C /opt/cni/bin
      eos

      unless Dir.exists?("./share")
        Dir.mkdir("./share")
      end
      config.vm.synced_folder "./share", "/share"

      if i == 1
        unless Dir.exists?("./.kube")
          Dir.mkdir("./.kube")
        end
        config.vm.synced_folder ".kube", "/root/hostkube"

        config.vm.provision "shell", inline: <<-eos
          [ -f /share/join ] && kubeadm reset
          sudo kubeadm init \
            --apiserver-advertise-address #{node_info.ip} \
            --apiserver-cert-extra-sans 127.0.0.1 \
            | grep 'kubeadm join --token' > /share/join

          cat /etc/kubernetes/admin.conf | sed s/#{node_info.ip.split(".").join('\.')}/127.0.0.1/ > /root/hostkube/config

          rm -rf /root/.kube
          mkdir -p /root/.kube
          cp /etc/kubernetes/admin.conf /root/.kube/config
        eos
        config.vm.network "forwarded_port", guest: 6443, host: 6443, guest_ip: node_info.ip, host_ip: "127.0.0.1"
      else
        config.vm.provision "shell", inline: "kubeadm reset && sudo bash -c 'eval $(cat /share/join)'"
      end
    end
  end
end