I am manage a group of VM and I need to setup all vm create a ssh tunnel to a specific host A. One way to do this is append public key of each VM to host's authorized_keys, but I guess I have to do the append each time i create a VM. So I am trying to config host A to accept pem or private key login without passowrd, just like EC2, client can use "ssh -i PEM" to login host A. But I have tried in vain for hours. I create a rsa public/private key and let VM use the private key to login, no matter what I do, host a still ask for password. Is there anything I missed ? Thanks.