[잡설] GCP 갑자기 로그인이 안되는 경우 해결방안

https://www.reddit.com/r/googlecloud/comments/6vhrgs/permission_denied_publickey/

1. edit the instance

2. go to the 'ssh keys' section, and add ssh key from local machine '~/.ssh/id_rsa.pub'. I usually just copy and paste the contents of the file to the web interface. The ssh key will have 'user@host' on the end, edit this to just have the username you require, leave off the @host portion.

3. save (you may need to restart also, but try without first).

중요한건 따라 했는데도 안됨 ㅜㅜ