标签：rac pop abi ati == ext toc 技术分享 keygen
参考：http://blog.csdn.net/universe_hao/article/details/52296811
首先，说明一下我们要做的是，serverA 服务器的 usera 用户免密码登录 serverB 服务器的 userb用户。
我们先使用usera 登录 serverA 服务器
- [root@serverA ~]# su - usera
- [usera@serverA ~]$ pwd
- /home/usera
然后在serverA上生成密钥对
- [usera@serverA ~]$ ssh-keygen -t rsa
- Generating public/private rsa key pair.
- Enter file in which to save the key (/home/usera/.ssh/id_rsa):
- Created directory ‘/home/usera/.ssh‘.
- Enter passphrase (empty for no passphrase):
- Enter same passphrase again:
- Your identification has been saved in /home/usera/.ssh/id_rsa.
- Your public key has been saved in /home/usera/.ssh/id_rsa.pub.
- The key fingerprint is:
- 39:f2:fc:70:ef:e9:bd:05:40:6e:64:b0:99:56:6e:01 usera@serverA
- The key‘s randomart image is:
- +--[ RSA 2048]----+
- | Eo* |
- | @ . |
- | = * |
- | o o . |
- | . S . |
- | + . . |
- | + . .|
- | + . o . |
- | .o= o. |
- +-----------------+
此时会在/home/usera/.ssh目录下生成密钥对
- [usera@serverA ~]$ ls -la .ssh
- 总用量 16
- drwx------ 2 usera usera 4096 8月 24 09:22 .
- drwxrwx--- 12 usera usera 4096 8月 24 09:22 ..
- -rw------- 1 usera usera 1675 8月 24 09:22 id_rsa
- -rw-r--r-- 1 usera usera 399 8月 24 09:22 id_rsa.pub
然后将公钥上传到serverB 服务器的，并以userb用户登录
- [usera@portalweb1 ~]$ ssh-copy-id userb@10.124.84.20
- The authenticity of host ‘10.124.84.20 (10.124.84.20)‘ can‘t be established.
- RSA key fingerprint is f0:1c:05:40:d3:71:31:61:b6:ad:7c:c2:f0:85:3c:cf.
- Are you sure you want to continue connecting (yes/no)? yes
- Warning: Permanently added ‘10.124.84.20‘ (RSA) to the list of known hosts.
- userb@10.124.84.29‘s password:
- Now try logging into the machine, with "ssh ‘userb@10.124.84.20‘", and check in:
-
- .ssh/authorized_keys
-
- to make sure we haven‘t added extra keys that you weren‘t expecting.
这个时候usera的公钥文件内容会追加写入到userb的 .ssh/authorized_keys 文件中
- [usera@serverA ~]$ cat .ssh/id_rsa.pub
- ssh-rsa AAAAB3NzaC1yc2EAAAABIwAAAQEA2dpxfvifkpswsbusPCUWReD/mfTWpDEErHLWAxnixGiXLvHuS9QNavepZoCvpbZWHade88KLPkr5XEv6M5RscHXxmxJ1IE5vBLrrS0NDJf8AjCLQpTDguyerpLybONRFFTqGXAc/ximMbyHeCtI0vnuJlvET0pprj7bqmMXr/2lNlhIfxkZCxgZZQHgqyBQqk/RQweuYAiuMvuiM8Ssk/rdG8hL/n0eXjh9JV8H17od4htNfKv5+zRfbKi5vfsetfFN49Q4xa7SB9o7z6sCvrHjCMW3gbzZGYUPsj0WKQDTW2uN0nH4UgQo7JfyILRVZtwIm7P6YgsI7vma/vRP0aw== usera@serverA
查看serverB服务器userb用户下的 ~/.ssh/authorized_keys文件，内容是一样的，此处我就不粘贴图片了。
- [userb@serverB ~]$ cat .ssh/authorized_keys
- ssh-rsa AAAAB3NzaC1yc2EAAAABIwAAAQEA2dpxfvifkpswsbusPCUWReD/mfTWpDEErHLWAxnixGiXLvHuS9QNavepZoCvpbZWHade88KLPkr5XEv6M5RscHXxmxJ1IE5vBLrrS0NDJf8AjCLQpTDguyerpLybONRFFTqGXAc/ximMbyHeCtI0vnuJlvET0pprj7bqmMXr/2lNlhIfxkZCxgZZQHgqyBQqk/RQweuYAiuMvuiM8Ssk/rdG8hL/n0eXjh9JV8H17od4htNfKv5+zRfbKi5vfsetfFN49Q4xa7SB9o7z6sCvrHjCMW3gbzZGYUPsj0WKQDTW2uN0nH4UgQo7JfyILRVZtwIm7P6YgsI7vma/vRP0aw== usera@serverA
另外我们要注意，.ssh目录的权限为700，其下文件authorized_keys和私钥的权限为600。否则会因为权限问题导致无法免密码登录。我们可以看到登陆后会有known_hosts文件生成。
- [useb@serverB ~]$ ls -la .ssh
- total 24
- drwx------. 2 useb useb 4096 Jul 27 16:13 .
- drwx------. 35 useb useb 4096 Aug 24 09:18 ..
- -rw------- 1 useb useb 796 Aug 24 09:24 authorized_keys
- -rw------- 1 useb useb 1675 Jul 27 16:09 id_rsa
- -rw-r--r-- 1 useb useb 397 Jul 27 16:09 id_rsa.pub
- -rw-r--r-- 1 useb useb 1183 Aug 11 13:57 known_hosts
这样做完之后我们就可以免密码登录了
- [usera@serverA ~]$ ssh userb@10.124.84.20
另外，将公钥拷贝到服务器的~/.ssh/authorized_keys文件中方法有如下几种：
1、将公钥通过scp拷贝到服务器上，然后追加到~/.ssh/authorized_keys文件中，这种方式比较麻烦。scp -P 22 ~/.ssh/id_rsa.pub user@host:~/。
2、通过ssh-copy-id程序，就是我演示的方法，ssh-copyid user@host即可
3、可以通过cat ~/.ssh/id_rsa.pub | ssh -p 22 user@host ‘cat >> ~/.ssh/authorized_keys’，这个也是比较常用的方法，因为可以更改端口号。
后记
如果操作不成功，原因可能是以前生成过.ssh文件，把原先的普通用户和root用户下的.ssh目录全删掉再重新生成，也许可以成功，
ssh免密码登陆
标签：rac pop abi ati == ext toc 技术分享 keygen
原文地址：http://www.cnblogs.com/regit/p/7998340.html
