确定SSH互信建立步骤是没有错的，做了N遍，就是不通过

[oracle@DataServer01 ~]$ mkdir ~/.ssh

[oracle@DataServer01 ~]$ chmod 755 ~/.ssh

[oracle@DataServer01 ~]$ ssh-keygen -t rsa

Generating public/private rsa key pair.

Enter file in which to save the key (/home/oracle/.ssh/id_rsa):

Enter passphrase (empty for no passphrase):

Enter same passphrase again:

Your identification has been saved in /home/oracle/.ssh/id_rsa.

Your public key has been saved in /home/oracle/.ssh/id_rsa.pub.

The key fingerprint is:

8f:5f:37:cf:73:8c:75:b7:8f:4a:25:bd:f0:76:c3:32 oracle@localhost.localdomain

The key's randomart image is:

+--[ RSA 2048]----+

|                 |

|                 |

|                 |

|             .   |

|        S   o o  |

|         o   =..+|

|        . . oE**=|

|         . o o+O+|

|          . ... B|

[oracle@localhost ~]$ ssh-keygen -t dsa

Generating public/private dsa key pair.

Enter file in which to save the key (/home/oracle/.ssh/id_dsa):

Enter passphrase (empty for no passphrase):

Enter same passphrase again:

Your identification has been saved in /home/oracle/.ssh/id_dsa.

Your public key has been saved in /home/oracle/.ssh/id_dsa.pub.

The key fingerprint is:

fc:b8:b2:77:81:64:d1:cb:72:68:b2:58:55:be:f9:df oracle@localhost.localdomain

The key's randomart image is:

[oracle@DataServer01 ~]$ cat ~/.ssh/id_rsa.pub >> ./.ssh/authorized_keys

[oracle@DataServer01 ~]$ cat ./.ssh/id_dsa.pub >> ~/.ssh/authorized_keys

[oracle@DataServer01 ~]$ ssh DataServer02 cat ~/.ssh/id_rsa.pub >> ~/.ssh/authorized_keys

[oracle@DataServer01 ~]$ ssh DataServer02 cat ~/.ssh/id_dsa.pub >> ~/.ssh/authorized_keys

[oracle@DataServer01 ~]$ scp ~/.ssh/authorized_keys DataServer02:~/.ssh/authorized_keys

[oracle@DataServer01 ~]$ exec /usr/bin/ssh-agent $SHELL

[oracle@DataServer01 ~]$ /usr/bin/ssh-add

Identity added: /home/oracle/.ssh/id_rsa (/home/oracle/.ssh/id_rsa)

Identity added: /home/oracle/.ssh/id_dsa (/home/oracle/.ssh/id_dsa)