ssh与ntp
1.配置ntp时间服务器，确保客户端主机能和服务主机同步时间
分析：首先客户端和服务主机同步，我们可以让客户端主机根据服务器主机进行同步，服务器主机从阿里云来进行同步
一，服务器主机从阿里云同步时间
[root@server ~]# vim /etc/chrony.conf
二，重启服务，查看服务器主机是否同步
[root@server ~]# systemctl restart chronyd
[root@server ~]# chronyc sources -v
.-- Source mode '^' = server, '=' = peer, '#' = local clock.
/ .- Source state '*' = current best, '+' = combined, '-' = not combined,
| / 'x' = may be in error, '~' = too variable, '?' = unusable.
|| .- xxxx [ yyyy ] +/- zzzz
|| Reachability register (octal) -. | xxxx = adjusted offset,
|| Log2(Polling interval) --. | | yyyy = measured offset,
|| \ | | zzzz = estimated error.
|| | | \
MS Name/IP address Stratum Poll Reach LastRx Last sample
===============================================================================
^* 203.107.6.88 2 6 17 9 +8156ns[ +654us] +/- 24ms
[root@server ~]# timedatectl status
Local time: 六 2023-03-18 19:32:49 CST
Universal time: 六 2023-03-18 11:32:49 UTC
RTC time: 六 2023-03-18 11:32:49
Time zone: Asia/Shanghai (CST, +0800)
System clock synchronized: yes
NTP service: active
RTC in local TZ: no
[root@server ~]# date
2023年 03月 18日 星期六 19:32:51 CST
三，配置允许访问的IP，并重启服务
[root@server ~]# vim /etc/chrony.conf 
四，对于客户端修改主配置文件中时间服务器地址，并重启服务
[root@server ~]# vim /etc/chrony.conf 
[root@server ~]# systemctl restart chronyd
五，查看客户端是否同步
[root@node1 ~]# systemctl restart chronyd
[root@node1 ~]# chronyc sources -v
.-- Source mode '^' = server, '=' = peer, '#' = local clock.
/ .- Source state '*' = current best, '+' = combined, '-' = not combined,
| / 'x' = may be in error, '~' = too variable, '?' = unusable.
|| .- xxxx [ yyyy ] +/- zzzz
|| Reachability register (octal) -. | xxxx = adjusted offset,
|| Log2(Polling interval) --. | | yyyy = measured offset,
|| \ | | zzzz = estimated error.
|| | | \
MS Name/IP address Stratum Poll Reach LastRx Last sample
===============================================================================
^? 192.168.38.128 3 6 3 1 -9426us[-9426us] +/- 26ms
[root@node1 ~]# timedatectl status
Local time: 六 2023-03-18 19:40:03 CST
Universal time: 六 2023-03-18 11:40:03 UTC
RTC time: 六 2023-03-18 11:40:03
Time zone: Asia/Shanghai (CST, +0800)
System clock synchronized: yes
NTP service: active
RTC in local TZ: no
[root@node1 ~]# date
2023年 03月 18日 星期六 19:40:09 CST
2.配置ssh免密登陆，能够通过客户端主机通过redhat用户和服务端主机基于公钥验证方式进行远程连接
分析：首先是使用客户端redhat用户去基于公钥验证进行连接，首先我们先增加个用户，因为是客户端去的redhat用户访问服务器端，所以我们需要在客户端redhat用户创建密钥然后发给客户端
一，创建新用户redhat
[root@node1 ~]# useradd redhat
[root@node1 ~]# passwd redhat
更改用户 redhat 的密码 。
新的密码：
重新输入新的密码：
passwd：所有的身份验证令牌已经成功更新。
二，创建新的密钥对，并且发送到指定目录
[redhat@node1 root]$ ssh-keygen -t rsa
Generating public/private rsa key pair.
Enter file in which to save the key (/home/redhat/.ssh/id_rsa):
Enter passphrase (empty for no passphrase):
Enter same passphrase again:
Your identification has been saved in /home/redhat/.ssh/id_rsa
Your public key has been saved in /home/redhat/.ssh/id_rsa.pub
The key fingerprint is:
SHA256:peN3IXp4nusrQ5Ca/umHNzX6fO6SPJSSf6LCnv2mNc8 redhat@node1
The key's randomart image is:
+---[RSA 3072]----+
| |
| |
| . . |
| o o |
| o .S.... |
| o .++=. . |
| . . o+B*o. |
| . ++BBO*o |
| +*++@X@E |
+----[SHA256]-----+
[redhat@node1 root]$
[redhat@node1 root]$ ssh-copy-id [email protected]
/usr/bin/ssh-copy-id: INFO: Source of key(s) to be installed: "/home/redhat/.ssh/id_rsa.pub"
/usr/bin/ssh-copy-id: INFO: attempting to log in with the new key(s), to filter out any that are already installed
/usr/bin/ssh-copy-id: INFO: 1 key(s) remain to be installed -- if you are prompted now it is to install the new keys
[email protected]'s password:
Number of key(s) added: 1
Now try logging into the machine, with: "ssh '[email protected]'"
and check to make sure that only the key(s) you wanted were added.
三，客户端测试
[redhat@node1 root]$ ssh [email protected]
Activate the web console with: systemctl enable --now cockpit.socket
Register this system with Red Hat Insights: insights-client --register
Create an account or view all your systems at https://red.ht/insights-dashboard
Last login: Sat Mar 18 19:58:18 2023 from 192.168.38.136
[root@server ~]#
[root@server ~]#
[root@server ~]#
此时便切换完成