文章目錄

• 1、目標
• 2、前期準備
• 3、生成公鑰
• 4、復制公鑰要其他節(jié)點
• 5、如何取消免密登錄

1、目標

通過ssh方式登錄各個主機，并且不需要輸入密碼，其中ssh命令的格式如下：

ssh [-l login_name] [-p port] [user@]hostname

2、前期準備

我這里的有幾臺CentOS7的虛擬機，虛擬機的主機名和IP地址如下所示：

192.168.223.131 hadoop-master 192.168.223.128 hadoop-slave1 192.168.223.129 hadoop-slave2 192.168.223.130 hadoop-slave3

如果以上內(nèi)容還沒有添加到hosts文件的需要先添加到hosts文件：

[root@hadoop-master ~]# vi /etc/hosts192.168.223.131 hadoop-master 192.168.223.128 hadoop-slave1 192.168.223.129 hadoop-slave2 192.168.223.130 hadoop-slave3

3、生成公鑰

首先使用

[root@hadoop-master hadoop]# ssh-keygen

然后連續(xù)回車就會出現(xiàn)下面內(nèi)容：

[root@hadoop-master hadoop]# 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: SHA256:XLxBYgPSJF0op8bKUYkRdCEHIjb4A2VczZsSsKXeUXU root@hadoop-master The key's randomart image is: +---[RSA 2048]----+ |+*XBOO+=* E | |=o+B=+B. * | | ooo.= o + | | .+.=.o. . o | | ..=.. S . | | o | | | | | | | +----[SHA256]-----+

通過如下的命令查看生成的.ssh目錄下文件

[root@hadoop-master ~]# cd ~ [root@hadoop-master ~]# ls -atrl|grep ssh drwx------. 2 root root 57 8月 8 16:17 .ssh

4、復制公鑰要其他節(jié)點

[root@hadoop-master ~]# cd ~ [root@hadoop-master ~]# ssh-copy-id -i .ssh/id_rsa.pub root@hadoop-slave1

然后輸入密碼會有如下內(nèi)容：

[root@hadoop-master ~]# ssh-copy-id -i .ssh/id_rsa.pub root@hadoop-slave1 /usr/bin/ssh-copy-id: INFO: Source of key(s) to be installed: ".ssh/id_rsa.pub" /usr/bin/ssh-copy-id: INFO: attempting to log in with the new key(s), to filter out any that are already installed /usr/bin/ssh-copy-id: INFO: 1 key(s) remain to be installed -- if you are prompted now it is to install the new keys root@hadoop-slave1's password: Number of key(s) added: 1Now try logging into the machine, with: "ssh 'root@hadoop-slave1'" and check to make sure that only the key(s) you wanted were added.

以上代表添加公鑰成功了。測試一下：

[root@hadoop-master ~]# ssh root@hadoop-slave1 Last failed login: Sat Aug 8 16:00:11 CST 2020 from hadoop-master on ssh:notty There was 1 failed login attempt since the last successful login. Last login: Sat Aug 8 15:53:42 2020 from 192.168.223.1 [root@hadoop-slave1 ~]#

從如上日志，我們可以看出我們已經(jīng)成功從hadoop-master主機登錄到了hadoop-slave1同理，我們將公鑰拷貝到其他服務(wù)器上

如果要幾個服務(wù)器之間都能免密登錄，需要將上面的步驟重復在幾臺主機上操作即可。

5、如何取消免密登錄

有時候免密登錄只是為了測試方便，測試完了還要恢復回去？如何操作？我們添加公鑰的時候是將將A主機的公鑰添加到B主機，如果A主機登錄B主機要輸入密碼則需要在B主機上去掉A的公鑰。比如下面的例子，我們在hadoop-slave1中去掉了hadoop-master的公鑰。

[root@hadoop-slave1 ~]# cd ./.ssh [root@hadoop-slave1 ~]# vi authorized_keys [root@hadoop-slave1 ~]#$ cat authorized_keys #ssh-rsa AAAAB3NzaC1yc2EAAAADAQABAAABAQDiUjCuy0zCFIwVkMRsHkn+SPk4oSAYIjmI9tRT1/7wS7nkaqhoK68fHosF07g6Hwl90Gx5yfXbz1qfQXhA8dVMJnNSkSsJHCSVbRcI5nqBZhVz3Ohj1YbGnPRSr23sIfPsZv2Ajvlfu/GQu0n7hkhWbbITxwxUabGU7UZ6QpiQnKPvFOvluSQWuZ296HkmxoeEhRGDedJGf2vHJyzKIypUZTe0R2eH1WOaaNNSXQa/OjBP/i4SnnU4oMaidPJt+KWHhvYatpuEF4RUhoR7FaGaysDw6lUATLfbhgYq86EmUzqEe+OwFwgYBDWQ80s9DfHp5OjsAxc8u3sBIGIuxgeP root@hadoop-master ssh-rsa AAAAB3NzaC1yc2EAAAADAQABAAABAQCcR6rzK2wk/y01qmhErV3PDRzU5rMPjylfipQfuymSnRl1pKTqyQll1Aw3QOX1/npkMxajqCQFr9UOrtRaxd/gricdGSuTh3IOw905fdwAmllaaRm6kNuQ4G+fN8t/LNWG8qqmvxjCi6MafOOZFDkUXMIakXxMSbCy6fp0e4vA3j5Kjq+rUPCHnid6Tb96zKlgeBsDbUxpYWj7VsfmlG16X+GrEMZ19T+eLoPIdT9jGEuw6N54oC3UWuhcSY2+dUD7acDQ3Ig1mp9JVe9N8jCaPIwbEc5rUOEkHhj4+CTqwkuK9fnm11I6RTuRt3x6oNQS9t60Eg/WRSPjx4hoC88p root@hadoop-slave2 ssh-rsa AAAAB3NzaC1yc2EAAAADAQABAAABAQC1ba/DQTS+rEeYsNQr+9C8WxbT2kWx9PSsOhEyR+dDCzKBlD0ssZJkQkXA9O9BBn8srrLTVSqiMs+A/DtkSasZCh7NO2QtNZzRP3UsVwPvqeeyYicKSIndo/FiKTEeCC3R/HkquAw2/d5YjDJkSHfrtlQxcJka755s/a5uXCL7CtYMU5kBG2J27dotm6uH11Sa9jihMGvAcllDTPBXQs3gENhU8nBXYEBof0lltvTmyiDRY4Onw+5z94fXG3n2S5aXNP8h7Ykkyjm20QbZqEYais62KMwv7bSIAQeBUZqpDjw5PMblHr9rNKTnpgLEE2Bx8CjRdZChAbM4kf9SpdzH root@hadoop-slave3

然后使用hadoop-master來遠程登錄hadoop-slave1的時候提示我們輸入密碼了

[root@hadoop-master ~]# ssh root@hadoop-slave1 root@hadoop-slave1's password:

總結(jié)

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