install() {
    # Install needed software once
    sudo apt install -y vagrant virtualbox
}
setup() {
    # Configure the virtual servers
    mkdir -p ssh/
    cp ~/.ssh/id_rsa.pub ssh/
    cat ssh/*.pub > authorized_keys
    cat >Vagrantfile <<'EOF'
Vagrant.configure("2") do |config|
  config.vm.box = "debian/buster64"
  config.vm.network "public_network"
  (1..100).each do |i|
    config.vm.define "vm%03d" % i do |node|
      node.vm.hostname = "vm%03d" % i
      # use the following line to map a range of ports on the host
      # to the VNC port of each VM:
      # node.vm.network "forwarded_port", host: 5900+i, guest: 5900
    end
  end

  config.vm.provision "shell" do |s|
    ssh_pub_key = File.readlines("authorized_keys").first.strip
    s.inline = <<-SHELL
      mkdir /root/.ssh
      echo #{ssh_pub_key} >> /home/vagrant/.ssh/authorized_keys
      echo #{ssh_pub_key} >> /root/.ssh/authorized_keys
      apt-get update
      apt-get install -y parallel
    SHELL
  end
end
EOF
}
start() {
    testssh() {
	ssh -o StrictHostKeyChecking=no -o UserKnownHostsFile=/dev/null root@"$1" echo "'$1'" '`uptime`'
    }
    export -f testssh
    # Start the virtual servers
    seq 100 | parallel vagrant up vm{}
    # After this it is possible to do:
    #   ssh 10.0.0.99
    # from another physical server
    # How do we get the IP-addresses?
    # parallel testssh
}
stop() {
    # Stop the virtual servers
    # After there is no running processes on the host server
    # and after this it is no longer possible to do:
    #   ssh 10.0.0.99
    # from another physical server
    # The host server returns to the state before running `start`
    vagrant suspend
}
destroy() {
    # Remove the setup
    # After this the host server returns to the state before running `setup`
    ?
}

full() {
    install
    setup
    start
    stop
    destroy
}