Linux实战技巧（1）CentOS虚拟机之间设置SSH免密登录
Linux实战技巧（2）使用Webmin搭建linux服务器WEB图形化管理页面
Linux实战技巧（3）多台Linux虚拟机集群环境设置时间同步
1、需求：现有三台虚拟机，设置三台虚拟机之间互相SSH登录时不需要密码
如三台虚拟机ip分别是：
192.168.1.201
192.168.1.202
192.168.1.203
2、操作步骤
- 1）首先在192.168.1.201 上执行如下命令：
ssh-keygen -t dsa
然后继续默认输入三次回车，如下：
- 2）分别在192.168.1.202和192.168.1.203上分别执行上述步骤1
- 3）在三台虚拟机上分别执行如下命令：
cat /root/.ssh/id_dsa.pub
如：
- 4）在192.168.1.201上的/root/.ssh/目录下创建authorized_keys文件，内容为上述步骤3中查询到的三个公钥
- 5）在192.168.1.202和192.168.1.203上分别按照上述步骤4执行，即在三台虚拟机上的/root/.ssh/目录下创建authorized_keys文件，然后将三台虚拟机上的ssh产生的公钥均放进去，即此时已经OK
- 6）验证：
(base) [root@redrose2100 ~]# ifconfig ens33
ens33: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1500
inet 192.168.1.201 netmask 255.255.255.0 broadcast 192.168.1.255
inet6 fe80::ffbc:4a04:cbc5:1ad2 prefixlen 64 scopeid 0x20<link>
inet6 fe80::8533:7fa:153f:d6a6 prefixlen 64 scopeid 0x20<link>
inet6 fe80::932c:a8f0:34a8:eb30 prefixlen 64 scopeid 0x20<link>
ether 00:0c:29:83:f8:64 txqueuelen 1000 (Ethernet)
RX packets 4941 bytes 3539336 (3.3 MiB)
RX errors 0 dropped 0 overruns 0 frame 0
TX packets 2170 bytes 234901 (229.3 KiB)
TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0
(base) [root@redrose2100 ~]# ssh 192.168.1.202
The authenticity of host '192.168.1.202 (192.168.1.202)' can't be established.
ECDSA key fingerprint is SHA256:GAtkLjUNBNYBgdP0BflGb20oNs7+6J3bAl/UOc4DEhw.
ECDSA key fingerprint is MD5:fd:e0:ea:11:2a:dc:80:9a:46:85:da:46:61:ab:c7:c3.
Are you sure you want to continue connecting (yes/no)? yes
Warning: Permanently added '192.168.1.202' (ECDSA) to the list of known hosts.
Last login: Thu Jun 10 23:37:53 2021 from 192.168.1.106
(base) [root@redrose2100 ~]# ifconfig ens33
ens33: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1500
inet 192.168.1.202 netmask 255.255.255.0 broadcast 192.168.1.255
inet6 fe80::ffbc:4a04:cbc5:1ad2 prefixlen 64 scopeid 0x20<link>
inet6 fe80::8533:7fa:153f:d6a6 prefixlen 64 scopeid 0x20<link>
ether 00:0c:29:75:8d:06 txqueuelen 1000 (Ethernet)
RX packets 4258 bytes 3481445 (3.3 MiB)
RX errors 0 dropped 0 overruns 0 frame 0
TX packets 1660 bytes 185878 (181.5 KiB)
TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0
(base) [root@redrose2100 ~]# ssh 192.168.1.203
The authenticity of host '192.168.1.203 (192.168.1.203)' can't be established.
ECDSA key fingerprint is SHA256:GAtkLjUNBNYBgdP0BflGb20oNs7+6J3bAl/UOc4DEhw.
ECDSA key fingerprint is MD5:fd:e0:ea:11:2a:dc:80:9a:46:85:da:46:61:ab:c7:c3.
Are you sure you want to continue connecting (yes/no)? yes
Warning: Permanently added '192.168.1.203' (ECDSA) to the list of known hosts.
Last login: Thu Jun 10 23:38:00 2021 from 192.168.1.106
(base) [root@redrose2100 ~]# ifconfig ens33
ens33: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1500
inet 192.168.1.203 netmask 255.255.255.0 broadcast 192.168.1.255
inet6 fe80::ffbc:4a04:cbc5:1ad2 prefixlen 64 scopeid 0x20<link>
inet6 fe80::8533:7fa:153f:d6a6 prefixlen 64 scopeid 0x20<link>
inet6 fe80::932c:a8f0:34a8:eb30 prefixlen 64 scopeid 0x20<link>
ether 00:0c:29:61:96:d5 txqueuelen 1000 (Ethernet)
RX packets 3951 bytes 3337413 (3.1 MiB)
RX errors 0 dropped 0 overruns 0 frame 0
TX packets 1822 bytes 310619 (303.3 KiB)
TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0
(base) [root@redrose2100 ~]# ssh 192.168.1.201
The authenticity of host '192.168.1.201 (192.168.1.201)' can't be established.
ECDSA key fingerprint is SHA256:GAtkLjUNBNYBgdP0BflGb20oNs7+6J3bAl/UOc4DEhw.
ECDSA key fingerprint is MD5:fd:e0:ea:11:2a:dc:80:9a:46:85:da:46:61:ab:c7:c3.
Are you sure you want to continue connecting (yes/no)? yes
Warning: Permanently added '192.168.1.201' (ECDSA) to the list of known hosts.
Last login: Thu Jun 10 23:37:40 2021 from 192.168.1.106
(base) [root@redrose2100 ~]# ifconfig ens33
ens33: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1500
inet 192.168.1.201 netmask 255.255.255.0 broadcast 192.168.1.255
inet6 fe80::ffbc:4a04:cbc5:1ad2 prefixlen 64 scopeid 0x20<link>
inet6 fe80::8533:7fa:153f:d6a6 prefixlen 64 scopeid 0x20<link>
inet6 fe80::932c:a8f0:34a8:eb30 prefixlen 64 scopeid 0x20<link>
ether 00:0c:29:83:f8:64 txqueuelen 1000 (Ethernet)
RX packets 5453 bytes 3597632 (3.4 MiB)
RX errors 0 dropped 0 overruns 0 frame 0
TX packets 2605 bytes 283014 (276.3 KiB)
TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0
(base) [root@redrose2100 ~]# exit
logout
Connection to 192.168.1.201 closed.
(base) [root@redrose2100 ~]# exit
logout
Connection to 192.168.1.203 closed.
(base) [root@redrose2100 ~]# exit
logout
Connection to 192.168.1.202 closed.
(base) [root@redrose2100 ~]#
