Machin A is my local pc.
Machine B is my remote vps pc,its ip is vps_ip.

Step 1: Create Authentication SSH-Kegen Keys on machine A

ssh-keygen -t rsa -P ''
Generating public/private rsa key pair.
Enter file in which to save the key (/root/.ssh/id_rsa):/root/.ssh/myvps
Your identification has been saved in /root/.ssh/myvps.
Your public key has been saved in /root/.ssh/myvps.pub.

Step2 Upload Generated Public Keys to machine B

scp /root/.ssh/myvps.pub root@vps_ip:/root/.ssh/authorized_keys

To login machine B with "ssh root@vps_ip" and execute
chmod 600 /root/.ssh/authorized_keys

To exit from machine B and relogin from machine A.

ssh root@vps_ip can't login without password ,why?

Have you examined the logs for clues?
Have you checked permissions on the home folders, and the .ssh folders, and the files within the .ssh folders?
Have you done anything else to detect the cause of the problem or resolve the issue that we should know about?
Have you considered using the ssh-copy-id script from the openssh package for transporting keys properly?

In addition.

ssh defaults to id_rsa. Have you tried

ssh -i ~/.ssh/myvps root@vps_IP

ssh-copy-id appends the selected public key to the authorized_keys files but there are many ways to accomplish the same task.

1 members found this post helpful.

Re: ssh-copy-id: it does, but also does some permission checks also. Generally the manual steps do not nuless you add those steps to the process. I like a combined approach, where I use the ssh-copy-id, but then also manually check and correct permissions and ownership that it ignores but ssh WILL check.