ssh面密码登录配置-hadoop安装准备

1. 用ssh-keygen创建公钥，一直回车即可

root@kali:~# ssh-keygen -t rsa
Generating public/private rsa key pair.
Enter file in which to save the key (/root/.ssh/id_rsa):
/root/.ssh/id_rsa already exists.
Overwrite (y/n)? 

2.  ssh本机，提示输入密码。。。

root@kali:~/.ssh# /etc/init.d/ssh start
[ ok ] Starting OpenBSD Secure Shell server: sshd.
root@kali:~/.ssh# ssh localhost
root@localhost's password: 

3. 将公钥拷为authorized_keys， 再实验ssh localhost，即可免密码登录

root@kali:~/.ssh# cp id_rsa.pub  authorized_keys
root@kali:~/.ssh# ls
authorized_keys  id_rsa  id_rsa.pub  known_hosts
root@kali:~/.ssh# ssh localhost
Linux kali 3.7-trunk--pae # SMP Debian 3.7.-+kali8 i686

The programs included with the Kali GNU/Linux system are free software;
the exact distribution terms for each program are described in the
individual files in /usr/share/doc/*/copyright.

Kali GNU/Linux comes with ABSOLUTELY NO WARRANTY, to the extent
permitted by applicable law.
Last login: Thu Dec 19 22:41:22 2013 from localhost

4. 将公钥拷至被管理机上，再试试。喔？？报错啦！

root@kali:~# ssh 192.168.0.102
@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@
@    WARNING: REMOTE HOST IDENTIFICATION HAS CHANGED!     @
@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@
IT IS POSSIBLE THAT SOMEONE IS DOING SOMETHING NASTY!
Someone could be eavesdropping on you right now (man-in-the-middle attack)!
It is also possible that a host key has just been changed.
The fingerprint for the RSA key sent by the remote host is
:4e:4f:2b:b4:::7c:d2:::be::8d:bb:5f.
Please contact your system administrator.
Add correct host key in /root/.ssh/known_hosts to get rid of this message.
Offending RSA key in /root/.ssh/known_hosts:
RSA host key for 192.168.0.102 has changed and you have requested strict checking.
Host key verification failed.

这种情况是因为要ssh的机器上的ssh重新安装或者系统重装了，导致RSA host key 失效，解决方法：cd ~/.ssh  然后 rm -f known_hosts 即可重新登录

root@kali:~/.ssh# scp id_rsa.pub root@192.168.0.102:~/.ssh/authorized_keys
id_rsa.pub                                                                                                          %       .4KB/s   :   

root@kali:~# more /etc/hosts
127.0.0.1    localhost
192.168.0.101   node1
192.168.0.102   node2
# The following lines are desirable for IPv6 capable hosts
::     localhost ip6-localhost ip6-loopback
ff02:: ip6-allnodes
ff02:: ip6-allrouters
root@kali:~# ssh node2
The authenticity of host 'node2 (192.168.0.102)' can't be established.
RSA key fingerprint is :4e:4f:2b:b4:::7c:d2:::be::8d:bb:5f.
Are you sure you want to continue connecting (yes/no)? yes
Warning: Permanently added 'node2' (RSA) to the list of known hosts.
Linux bt 3.2. # SMP Fri Feb  :: EST  i686 GNU/Linux

  System information as of Mon Mar   :: CST 

  System load:  0.0                Processes:
  Usage of /:   41.9% of .15GB   Users logged in:
  Memory usage: %                 IP address for eth1: 192.168.0.102
  Swap usage:   %

  Graph this data and manage this system at https://landscape.canonical.com/
Last login: Mon Mar   ::
root@bt:~# 这里已经登入了。。。

在此，已经完成了管理节点到被管理节点的免密码登录。

5. 将两机的authorized_keys文件合并。拷贝至两台机器上， 即可实现双机互相面密码登录

root@bt:~/.ssh# cat id_rsa.pub >>authorized_keys 

root@kali:~/.ssh# scp root@node2:~/.ssh/authorized_keys .
authorized_keys                                                                                                     %       .8KB/s   :    

root@bt:~/.ssh# ssh node1
The authenticity of host 'node1 (192.168.0.101)' can't be established.
RSA key fingerprint is ::d5:b1:ae::0f:1d:3d:3d:::9f:6f:e1:7c.
Are you sure you want to continue connecting (yes/no)? yes
Warning: Permanently added 'node1,192.168.0.101' (RSA) to the list of known hosts.
Linux kali 3.7-trunk--pae # SMP Debian 3.7.-+kali8 i686

The programs included with the Kali GNU/Linux system are free software;
the exact distribution terms for each program are described in the
individual files in /usr/share/doc/*/copyright.

Kali GNU/Linux comes with ABSOLUTELY NO WARRANTY, to the extent
permitted by applicable law.
Last login: Mon Mar  3 21:19:04 2014 from localhost
root@kali:~#  这里实现了node2 登录node1