如何安全地获取并检查“known_hosts”的主机公钥？

Question

对于新部署的实例，我第一次 SSH 连接时收到以下消息：

The authenticity of host '[hostname] ([IP address])' can't be established.
RSA key fingerprint is [key fingerprint].
Are you sure you want to continue connecting (yes/no)?

我想避免与用户的这种互动。

如何安全的获取、查看和保存这个公钥？