.1 在服务端主机上安装ntp服务：
yum install ntp
1.2 修改/etc/ntp.conf文件，将默认的ntp服务器地址替换为可用的ntp服务器地址。例如：
server ntp1.aliyun.com iburst server ntp2.aliyun.com iburst server ntp3.aliyun.com iburst
1.3 启动ntp服务并将其设置为开机自启动：
systemctl start ntpd systemctl enable ntpd
1.4 在客户端主机上安装ntp服务，并将其配置为同步服务端主机的时间：
yum install ntp ntpdate [服务端IP地址]
- 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的步骤如下：
检查 更新后找不到ntp包 于是掉头检查了yum源 没有问题
问了gtp发现二者存一即可
2.1 在客户端主机上使用ssh-keygen命令生成密钥：
ssh-keygen -t rsa[root@localhost ~]# ssh-keygen
Generating public/private rsa key pair.
Enter file in which to save the key (/root/.ssh/id_rsa): Created directory '/root/.ssh'.
Enter passphrase (empty for no passphrase):
Enter same passphrase again:
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:
SHA256:irRO8IKD7MTtVa4b1xAAzaQTZ/woxYHq+I6KNBYS01o root@localhost.localdomain
The key's randomart image is:
+---[RSA 3072]----+
| oO*. |
| . .=*. |
|o Eo. o. |
| * ... .. |
|=.. o oS |
|*oo+ oo.o |
|+O..=o.o . |
|*o++. + |
|=o...o. |
+----[SHA256]-----+
发现防火墙问题 检查防火墙
2.2 将生成的公钥（默认为~/.ssh/id_rsa.pub）复制到服务端主机上的~/.ssh/authorized_keys文件中：上传秘钥
成功
2.3 修改服务端主机的ssh配置文件/etc/ssh/sshd_config，确保以下选项被启用：
PubkeyAuthentication yes AuthorizedKeysFile .ssh/authorized_keys
2.4 重启ssh服务：
systemctl restart sshd
测试
[redhat@client .ssh]$ ssh 192.168.227.128
The authenticity of host '192.168.227.128 (192.168.227.128)' can't be established.
ED25519 key fingerprint is SHA256:IjiKi+oexrRWTbUACwNqXYQvu2F8yakPx49b7PW9lto.
This key is not known by any other names
Are you sure you want to continue connecting (yes/no/[fingerprint])? yes
Warning: Permanently added '192.168.227128' (ED25519) to the list of known hosts.
redhat@192.168.227.128's password:
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 Apr 18 11:10:12 2023
[redhat@server ~]$
