Linux实现免密登录

1.Linux下生成密钥

ssh-keygen的命令手册,通过”man ssh-keygen“命令:

Linux下实现免密码登录(超详细)/张生荣

通过命令”ssh-keygen -t rsa“

Linux下实现免密码登录(超详细)/张生荣

生成之后会在用户的根目录生成一个 “.ssh”的文件夹

Linux下实现免密码登录(超详细)/张生荣

进入“.ssh”会生成以下几个文件

Linux下实现免密码登录(超详细)/张生荣

authorized_keys:存放远程免密登录的公钥,主要通过这个文件记录多台机器的公钥

id_rsa : 生成的私钥文件

id_rsa.pub : 生成的公钥文件

know_hosts : 已知的主机公钥清单

如果希望ssh公钥生效需满足至少下面两个条件:

1) .ssh目录的权限必须是700

2) .ssh/authorized_keys文件权限必须是600

2.远程免密登录

原理图:

Linux下实现免密码登录(超详细)/张生荣

  常用以下几种方法:

 2.1 通过ssh-copy-id的方式

命令: ssh-copy-id -i ~/.ssh/id_rsa.put <romte_ip>

举例:

[root@test .ssh]# ssh-copy-id -i ~/.ssh/id_rsa.pub 192.168.91.135

root@192.168.91.135's password:

Now try logging into the machine, with "ssh '192.168.91.135'", and check in:

.ssh/authorized_keys

to make sure we haven't added extra keys that you weren't expecting.

[root@test .ssh]# ssh root@192.168.91.135

Last login: Mon Oct 10 01:25:49 2016 from 192.168.91.133

[root@localhost ~]#

常见错误:

[root@test ~]# ssh-copy-id -i ~/.ssh/id_rsa.pub 192.168.91.135

-bash: ssh-copy-id: command not found //提示命令不存在

解决办法:yum -y install openssh-clients

2.2 通过scp将内容写到对方的文件中

命令:scp -p ~/.ssh/id_rsa.pub root@<remote_ip>:/root/.ssh/authorized_keys

举例:

[root@test .ssh]# scp -p ~/.ssh/id_rsa.pub root@192.168.91.135:/root/.ssh/authorized_keys

root@192.168.91.135's password:

id_rsa.pub 100% 408 0.4KB/s 00:00

[root@test .ssh]#

[root@test .ssh]#

[root@test .ssh]#

[root@test .ssh]# ssh root@192.168.91.135

Last login: Mon Oct 10 01:27:02 2016 from 192.168.91.133

[root@localhost ~]#

也可以分为两步操作:

$ scp ~/.ssh/id_rsa.pub root@<remote_ip>:pub_key //将文件拷贝至远程服务器

$ cat ~/pub_key >>~/.ssh/authorized_keys //将内容追加到authorized_keys文件中, 不过要登录远程服务器来执行这条命令

2.3 通过Ansible实现批量免密

2.3.1 将需要做免密操作的机器hosts添加到/etc/ansible/hosts下:

[Avoid close]

192.168.91.132

192.168.91.133

192.168.91.134

2.3.2 执行命令进行免密操作

ansible <groupname> -m authorized_key -a "user=root key='{{ lookup('file','/root/.ssh/id_rsa.pub') }}'" -k

示例:

[root@test sshpass-1.05]# ansible test -m authorized_key -a "user=root key='{{ lookup('file','/root/.ssh/id_rsa.pub') }}'" -k

  SSH password: ----->输入密码

  192.168.91.135 | success >> {

  "changed": true,

  "key": "ssh-rsa    AAAAB3NzaC1yc2EAAAABIwAAAQEArZI4kxlYuw7j1nt5ueIpTPWfGBJoZ8Mb02OJHR8yGW7A3izwT3/uhkK7RkaGavBbAlprp5bxp3i0TyNxa/apBQG5NiqhYO8YCuiGYGsQAGwZCBlNLF3gq1/18B6FV5moE/8yTbFA4dBQahdtVP PejLlSAbb5ZoGK8AtLlcRq49IENoXB99tnFVn3gMM0aX24ido1ZF9RfRWzfYF7bVsLsrIiMPmVNe5KaGL9kZ0svzoZ708yjWQQCEYWp0m+sODbtGPC34HMGAHjFlsC/SJffLuT/ug/hhCJUYeExHIkJF8OyvfC6DeF7ArI6zdKER7D8M0SM  WQmpKUltj2nltuv3w== root@localhost.localdomain",

  "key_options": null,

  "keyfile": "/root/.ssh/authorized_keys",

  "manage_dir": true,

  "path": null,

  "state": "present",

  "unique": false,

  "user": "root"

  }

  [root@test sshpass-1.05]#

2.4 手工复制粘贴的方式

将本地id_rsa.pub文件的内容拷贝至远程服务器的~/.ssh/authorized_keys文件中

以上所述是小编给大家介绍的Linux下实现免密码登录,希望对大家有所帮助!

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