配置网络yum源报错问题

现象：服务器可以正常上网，且yum源文件配置是准确无误的

报错信息如下：

[root@localhost ~]# yum list
Loaded plugins: fastestmirror
https://mirrors.aliyun.com/centos/7/os/x86_64/repodata/repomd.xml: [Errno 14] curl#60 - "Peer's Certificate has expired."
Trying other mirror.
It was impossible to connect to the CentOS servers.
This could mean a connectivity issue in your environment, such as the requirement to configure a proxy,
or a transparent proxy that tampers with TLS security, or an incorrect system clock.
Please collect information about the specific failure that occurs in your environment,
using the instructions in: https://access.redhat.com/solutions/1527033 and create a bug on https://bugs.centos.org/



 One of the configured repositories failed (centos),
 and yum doesn't have enough cached data to continue. At this point the only
 safe thing yum can do is fail. There are a few ways to work "fix" this:

     1. Contact the upstream for the repository and get them to fix the problem.

     2. Reconfigure the baseurl/etc. for the repository, to point to a working
        upstream. This is most often useful if you are using a newer
        distribution release than is supported by the repository (and the
        packages for the previous distribution release still work).

     3. Disable the repository, so yum won't use it by default. Yum will then
        just ignore the repository until you permanently enable it again or use
        --enablerepo for temporary usage:

            yum-config-manager --disable centos

     4. Configure the failing repository to be skipped, if it is unavailable.
        Note that yum will try to contact the repo. when it runs most commands,
        so will have to try and fail each time (and thus. yum will be be much
        slower). If it is a very temporary problem though, this is often a nice
        compromise:

            yum-config-manager --save --setopt=centos.skip_if_unavailable=true

failure: repodata/repomd.xml from centos: [Errno 256] No more mirrors to try.
https://mirrors.aliyun.com/centos/7/os/x86_64/repodata/repomd.xml: [Errno 14] curl#60 - "Peer's Certificate has expired."

 解决办法：

可能是由于服务器时间不正确导致https证书认证错误
更新服务器时间即可
例:
date -s “2018-11-18 12:00:00”
或者
ntpdate 0.asia.pool.ntp.org

参考网站：

https://cloud.tencent.com/developer/article/1372484