Hadoop分布式集群搭建之--SSH无密登录配置

1、配置ssh实现hadoop100免秘钥登录hdoop101和hadoop102。

2、免秘钥登录原理如下图所示：

3、生成公钥和私钥：

 注：本操作hadoop用户已经创建，执行路径为/home/hadoop/.ssh

[hadoop@hadoop100 .ssh]$ ssh-keygen -t rsa

注：然后敲（三个回车），就会生成两个文件id_rsa（私钥）、id_rsa.pub（公钥），显示如下：

[hadoop@hadoop100 .ssh]$ ssh-keygen -t rsa
Generating public/private rsa key pair.
Enter file in which to save the key (/home/hadoop/.ssh/id_rsa): 
Enter passphrase (empty for no passphrase): 
Enter same passphrase again: 
Your identification has been saved in /home/hadoop/.ssh/id_rsa.
Your public key has been saved in /home/hadoop/.ssh/id_rsa.pub.
The key fingerprint is:
2b:c1:10:22:cc:0f:9d:c9:f1:57:28:be:c5:71:17:1b hadoop@hadoop100
The key's randomart image is:
+--[ RSA 2048]----+
|+ +.=   .. E.    |
| = *.o o.. .o    |
|  o o.o.o ..     |
|   . +.o         |
|      = S        |
|     . . .       |
|      . .        |
|       .         |
|                 |
+-----------------+

4、将公钥分别拷贝到要免秘钥登录的机器上（hadoop101,hadoop102）

[hadoop@hadoop100 .ssh]$ ssh-copy-id hadoop101
[hadoop@hadoop100 .ssh]$ ssh-copy-id hadoop102

注意：ssh访问自己也需要输入密码，所以我们需要将公钥也拷贝给hadoop100

[hadoop@hadoop100 .ssh]$ ssh-copy-id hadoop100

5、测试免秘钥登录是否成功

[hadoop@hadoop100 .ssh]$ ssh hadoop101
Last login: Mon Jul 22 20:22:44 2019 from 192.168.1.10
[hadoop@hadoop101 ~]$ exit
logout
Connection to hadoop101 closed.
[hadoop@hadoop100 .ssh]$ ssh hadoop102
Last login: Mon Jul 22 20:22:53 2019 from 192.168.1.10
[hadoop@hadoop102 ~]$ 

6、.ssh文件夹下（/home/hadoop/.ssh）的文件功能解释

known_hosts	记录ssh访问过计算机的公钥(public key)
id_rsa	生成的私钥
id_rsa.pub	生成的公钥
authorized_keys	存放授权过得无密登录服务器公钥