1.切入/root/.ssh路径下，使用 ssh-keygen获取主机key。
注：直接回车即可，无需输入任何信息。
[root@likeadmin ~/.ssh]# ssh-keygen
Generating public/private rsa key pair.
Enter file in which to save the key (/root/.ssh/id_rsa):
Enter passphrase (empty for no passphrase):
Enter same passphrase again:
Your identification has been saved in /root/.ssh/id_rsa.
Your public key has been saved in /root/.ssh/id_rsa.pub.
The key fingerprint is:
SHA256:wHcQJ9gL4yUdpYnxOnMU3HRigDkL5hT4C5itp1E0eAA root@likeadmin
The key's randomart image is:
+---[RSA 2048]----+
|Eo ....BBB* . |
|. = +.O+=O.o |
| * * o+B*.. |
|o + o o=.. |
| o . .+ S |
|o . . + |
| + |
|. |
| |
+----[SHA256]-----+
[root@likeadmin ~/.ssh]#
2.检查生成的key文件
[root@likeadmin ~/.ssh]# ls -l
total 12
-rw-------. 1 root root 1675 Apr 3 16:47 id_rsa
-rw-r--r--. 1 root root 396 Apr 3 16:47 id_rsa.pub
-rw-r--r--. 1 root root 177 Apr 3 16:41 known_hosts
[root@likeadmin ~/.ssh]#
3.使用ssh-copy-id -i /root/.ssh/id_rsa.pub root@192.168.164.129生成到目标主机key。
注：192.168.164.129为目标主机IP。
[root@likeadmin ~/.ssh]# ssh-copy-id -i /root/.ssh/id_rsa.pub root@192.168.164.129
/bin/ssh-copy-id: INFO: Source of key(s) to be installed: "/root/.ssh/id_rsa.pub"
/bin/ssh-copy-id: INFO: attempting to log in with the new key(s), to filter out any that are already installed
/bin/ssh-copy-id: INFO: 1 key(s) remain to be installed -- if you are prompted now it is to install the new keys
root@192.168.164.129's password: 注：此次输入目标主机root密码。
Number of key(s) added: 1
Now try logging into the machine, with: "ssh 'root@192.168.164.129'"
and check to make sure that only the key(s) you wanted were added.
[root@likeadmin ~/.ssh]#
4.测试到ssh免密到目标主机
[root@likeadmin ~/.ssh]# ssh 192.168.164.129
Last login: Tue Apr 2 16:21:12 2019
[root@likenode ~]#
[root@likenode ~]# hostname
likenode
[root@likenode ~]# exit
[root@likeadmin ~/.ssh]#