ssh_pub_key = File.readlines("../../../id_rsa_vagrant.pub").first.strip
$shell_centos7 = <<-SHELL
echo #{ssh_pub_key} >> /home/vagrant/.ssh/authorized_keys
SHELL
Vagrant.configure("2") do |config|
...
nodeconfig.vm.network "public_network"
...
nodeconfig.vm.provision "shell", inline: $shell_centos7
...