ssh免输入密码

一，ssh远程登录服务器

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

同理 本地电脑登录服务器

//首先登录a服务器，然后生成密钥对
[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. |  
+-----------------+

根目录下，查看生成的密匙对

[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

上传公钥到服务器ssh-copy-id aname@id

[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

//查看a服务器的id_rsa.pub
[usera@serverA ~]$ cat .ssh/id_rsa.pub 
ssh-rsa AAAAB3NzaC1yc2EAAAABIwAAAQEA2dpxfvifkpswsbusPCUWReD/mfTWpDEErHLWAxnixGiXLvHuS9QNavepZoCvpbZWHade88KLPkr5XEv6M5RscHXxmxJ1IE5vBLrrS0NDJf8AjCLQpTDguyerpLybONRFFTqGXAc/ximMbyHeCtI0vnuJlvET0pprj7bqmMXr/2lNlhIfxkZCxgZZQHgqyBQqk/RQweuYAiuMvuiM8Ssk/rdG8hL/n0eXjh9JV8H17od4htNfKv5+zRfbKi5vfsetfFN49Q4xa7SB9o7z6sCvrHjCMW3gbzZGYUPsj0WKQDTW2uN0nH4UgQo7JfyILRVZtwIm7P6YgsI7vma/vRP0aw== usera@serverA
//查看b服务器的authorized_keys,相同表示ok
[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b服务器，.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。

以后就可以免密码登录服务器b了

[usera@serverA ~]$ ssh userb@10.124.84.25

----------------------review-------------------

//其实也就两步
//生成密匙对
ssh-keygen -t rsa

//复制id_rsa.pub到服务器
ssh-copy-id 用户名@ip

----------------------github免密码-------------------

//cd 仓库dir
cd .git
vim config

// 修改url地址为ssh方式
[core]
        repositoryformatversion = 0
        filemode = false
        bare = false
        logallrefupdates = true
        symlinks = false
        ignorecase = true
        hideDotFiles = dotGitOnly
[remote "origin"]
        url = git@github.com:dongsongshan/dongsongshan.github.io
        fetch = +refs/heads/*:refs/remotes/origin/*
[branch "master"]
        remote = origin
        merge = refs/heads/master

----------------------review 2018-4-12 -------------------

    本地电脑免密码登录服务器
    
    查看是否存在id_ras和id_ras.pub两个文件(~/.ssh/)

    有的话直接用ssh-copy-id 用户名@ip

09 Aug 2017

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