CentOs7.3 Hadoop ssh 免密登陆

环境

三台虚拟机(IP)：

• 192.168.252.121
• 192.168.252.122
• 192.168.252.123

1.修改主机名

修改三台主机名，以此类推，node1，node3，node3

命令格式

hostnamectl set-hostname <hostname>

sudo hostnamectl set-hostname node1

剩下的虚拟机依次修改hostnamectl set-hostname[1-3]

重启操做系统

$ reboot

2.修改映射关系

1.在 node1 的 /etc/hosts 文件下添加以下内容

su hadoop
vi /etc/hosts

2.查看修改后的/etc/hosts 文件内容

$ cat /etc/hosts
127.0.0.1   localhost localhost.localdomain localhost4 localhost4.localdomain4
::1         localhost localhost.localdomain localhost6 localhost6.localdomain6
# 如下是添加的
192.168.252.121 node1
192.168.252.122 node2
192.168.252.123 node3

2.将集群node1 上的文件hosts文件 经过 scp 命令复制发送到集群的每个节点

for a in {1..3} ; do sudo scp /etc/hosts hadoop@node$a:/etc/hosts ; done

3.检查是否集群每个节点的 hosts 文件都已经修改过来了

for a in {1..3} ; do sudo ssh hadoop@node$a cat /etc/hosts ; done

3.启动 ssh 无密登陆

1.在集群node1的 /etc/ssh/sshd_config 文件去掉如下选项的注释

sudo vi /etc/ssh/sshd_config

RSAAuthentication yes      #开启私钥验证
PubkeyAuthentication yes   #开启公钥验证

2.将集群node1 修改后的 /etc/ssh/sshd_config 经过 scp 命令复制发送到集群的每个节点

for a in {1..3} ; do  sudo scp /etc/ssh/sshd_config hadoop@node$a:/etc/ssh/sshd_config ; done

4.生成公钥、私钥

1.在集群的每个节点节点输入命令 ssh-keygen -t rsa -P ''，生成 key，一概回车

ssh-keygen -t rsa -P ''

Generating public/private rsa key pair.
Enter file in which to save the key (/home/hadoop/.ssh/id_rsa): 
Created directory '/home/hadoop/.ssh'.
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:
aa:be:0e:46:9a:e8:d5:dc:79:ea:5a:b8:9b:08:e2:dd hadoop@node2
The key's randomart image is:
+--[ RSA 2048]----+
|                 |
|                 |
|                 |
|                 |
|  .     S        |
|.+  o o..        |
|=.o. +.+ .       |
|+.+.o.+ o        |
| o ==E+o         |
+-----------------+

2.在集群的node1 节点输入命令

将集群每个节点的公钥id_rsa.pub放入到本身的认证文件中authorized_keys;

for a in {1..3}; do sudo ssh hadoop@node$a cat /home/hadoop/.ssh/id_rsa.pub >> /home/hadoop/.ssh/authorized_keys; done

3.在集群的node1 节点输入命令

将本身的认证文件 authorized_keys 经过 scp 命令复制发送到每个节点上去: /home/hadoop/.ssh/authorized_keys`

for a in {1..3}; do sudo scp /home/hadoop/.ssh/authorized_keys hadoop@node$a:/home/hadoop/.ssh/authorized_keys ; done

4.非ROOT 用户需赋权限

chmod 700 /home/hadoop/.ssh/
chmod 700 /home/hadoop/
chmod 600 /home/hadoop/.ssh/authorized_keys

5.在集群的每个节点节点输入命令

接重启ssh服务

sudo systemctl restart sshd.service

6.验证 ssh 无密登陆

开一个其余窗口测试下可否免密登录

例如：在node3

ssh hadoop@node2

exit 退出

[hadoop@node1 ~]# exit
logout
Connection to node1 closed.

注意：开新的其余窗口测试下可否免密登录，把当前窗口都关了

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