ssh_config_bastion

Host *.example.internal
  ProxyCommand ssh -W %h:%p bastion -F group_vars/site-location/dot_ssh/ssh_config
  User aws-user-internal
  IdentityFile ~/.ssh/id_rsa_hostname

Host bastion
  Hostname example.com
  User ec2
  IdentityFile ~/.ssh/id_rsa_hostname2
  ForwardAgent yes
  ControlMaster auto
  ControlPath ~/.ssh/ansible-%r@%h:%p
  ControlPersist 5m
  StrictHostKeyChecking no
  UserKnownHostsFile=/dev/null