SSH 无密码远程执行脚本

　　ssh无密码登录及远程执行脚本要使用公钥与私钥。linux下可以用用ssh-keygen生成公钥/私钥对，下面我以CentOS7为例。

　　测试环境：机器A(10.0.224.80)；机器B(192.168.7.172)。现想A通过ssh免密码在B上远程执行命令。

　　1、首先在A机下生成公钥/私钥对：（-P表示密码，-P '' 就表示空密码，一次回车即可。在~/.ssh会生成id_rsa和id_rsa.pub两个文件）

[root@registry home]# ssh-keygen -t rsa -P ''
Generating public/private rsa key pair.
Enter file in which to save the key (/root/.ssh/id_rsa):    （直接回车）
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:
e8:a1:c0:cc:d0:2c:88:82:35:0f:c7:75:2b:79:14:72 root@registry
The key's randomart image is:
+--[ RSA 2048]----+
|  +...o E.       |
|++ =.  * .       |
|B o . o o        |
|.*     +         |
|  =   o S        |
|   . o .         |
|    . .          |
|                 |
|                 |
+-----------------+
[root@registry home]# cd ~/.ssh/
[root@registry .ssh]# ll
总用量 12
-rw-------. 1 root root 1675 4月   5 13:27 id_rsa
-rw-r--r--. 1 root root  395 4月   5 13:27 id_rsa.pub
-rw-r--r--. 1 root root 2492 4月   5 10:52 known_hosts

　　2、将A机下的id_rsa.pub复制到B机下

[root@registry .ssh]# scp ~/.ssh/id_rsa.pub root@192.168.7.172:/home
root@192.168.7.172's password: 
id_rsa.pub                                                                   100%  395     0.4KB/s   00:00    

　　3、在B机上，将从A机复制的id_rsa.pub添加到~/.ssh/authorzied_keys文件里，并赋予权限

[root@CCC ~]# cat /home/id_rsa.pub >> ~/.ssh/authorized_keys
[root@CCC ~]# chmod 600 ~/.ssh/authorized_keys

　　4、测试（注，第一次登录时需要手动输入yes）

　　　　执行远程命令

[root@registry home]# ssh root@192.168.7.172 "cd /home; ls"
calico.tar
laizy
nagios
ubuntu.tar
[root@registry home]# ssh root@192.168.7.172 "ifconfig ens33"
ens33: flags=4163<UP,BROADCAST,RUNNING,MULTICAST>  mtu 1500
        inet 192.168.7.172  netmask 255.255.255.0  broadcast 192.168.7.255
        inet6 fe80::20c:29ff:fecd:7e7c  prefixlen 64  scopeid 0x20<link>
        ether 00:0c:29:cd:7e:7c  txqueuelen 1000  (Ethernet)
        RX packets 216165  bytes 20851014 (19.8 MiB)
        RX errors 0  dropped 0  overruns 0  frame 0
        TX packets 198202  bytes 19741868 (18.8 MiB)
        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0

[root@registry home]# 

　　　　免密码，远程登录

[root@registry home]# ssh root@192.168.7.172
Last login: Tue Apr  5 12:04:26 2016 from 192.168.7.146
[root@CCC ~]# ifconfig ens33
ens33: flags=4163<UP,BROADCAST,RUNNING,MULTICAST>  mtu 1500
        inet 192.168.7.172  netmask 255.255.255.0  broadcast 192.168.7.255
        inet6 fe80::20c:29ff:fecd:7e7c  prefixlen 64  scopeid 0x20<link>
        ether 00:0c:29:cd:7e:7c  txqueuelen 1000  (Ethernet)
        RX packets 217411  bytes 20974871 (20.0 MiB)
        RX errors 0  dropped 0  overruns 0  frame 0
        TX packets 199328  bytes 19856521 (18.9 MiB)
        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0