在CentOS/RHEL上设置SSH免密码登录的方法

[root@node1 ~]# ssh root@192.168.0.10
The authenticity of host '192.168.0.10 (192.168.0.10)' can't be established.
RSA key fingerprint is 6d:8f:63:9b:3b:63:e1:72:b3:06:a4:e4:f4:37:21:42.
Are you sure you want to continue connecting (yes/no)&＃63; yes
Warning: Permanently added '192.168.0.10' (RSA) to the list of known hosts.
root@192.168.0.10's password:
Last login: Thu Dec 10 22:04:55 2015 from 192.168.0.1
[root@node2 ~]#

[root@node1 ~]# 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:
b4:51:7e:1e:52:61:cd:fb:b2:98:4b:ad:a1:8b:31:6d root@node1.ehowstuff.local
The key's randomart image is:
+--[ RSA 2048]----+
|     . ++  |
|     o o o |
|    o o o . |
|    . o + .. |
|    S  . . |
|     .  .. .|
|    o E oo.o |
|     = ooo. |
|    . o.o.  |
+-----------------+

[root@node1 ~]# ssh-copy-id -i ~/.ssh/id_rsa.pub 192.168.0.10
root@192.168.0.10's password:
Now try logging into the machine, with "ssh '192.168.0.10'", and check in:
.ssh/authorized_keys
to make sure we haven't added extra keys that you weren't expecting.

[root@node1 ~]# ssh root@192.168.0.10
Last login: Sun Dec 13 14:03:20 2015 from www.ehowstuff.local