Setup vagrant to use existing ssh key

Set insert_key to false, prevent vagrant from generating new key
then set our own ssh private key to be used, first priority
finally, copy our own ssh public key into vm as authorized key

Vagrantfile

@@ -22,12 +22,15 @@ Vagrant.configure("2") do |config|
       auto_correct: true
   end
 
-
   config.vm.provider :virtualbox do |vb|
     vb.customize ["modifyvm", :id, "--natdnshostresolver1", "on"]
     vb.memory = "2048"
   end
 
+  config.ssh.insert_key = false
+  config.ssh.private_key_path = ["~/.ssh/id_rsa", "~/.vagrant.d/insecure_private_key"]
+  config.vm.provision "file", source: "~/.ssh/id_rsa.pub", destination: "~/.ssh/authorized_keys"
+
   config.vm.provision "shell", inline: <<-SHELL
     if [ -f /vagrant/localenv.sh ]; then
       . /vagrant/localenv.sh