记一次执行yum命令报错：Could not retrieve mirrorlist http://mirrorlist.centos.org/

执行yum安装命令时报如下错误：

root@docker-test101 ~]# vi /etc/hosts
[root@docker-test101 ~]# yum install openssl* -y
Loaded plugins: fastestmirror, langpacks
Could not retrieve mirrorlist http://mirrorlist.centos.org/?release=7&arch=x86_64&repo=os&infra=stock error was
14: curl#7 - "Failed to connect to 2604:1380:2001:d00::3: Network is unreachable"


 One of the configured repositories failed (Unknown),
 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. Run the command with the repository temporarily disabled
            yum --disablerepo= ...

     4. Disable the repository permanently, 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 <repoid>
        or
            subscription-manager repos --disable=<repoid>

     5. 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=<repoid>.skip_if_unavailable=true

Cannot find a valid baseurl for repo: base/7/x86_64

综合其他博友的解决方法：
（1）、DNS配置国内DNS解析地址：

[root@docker-test101 ~]# vim /etc/resolv.conf 
# Generated by NetworkManager
nameserver 114.114.114.114
nameserver 114.114.114.115

（2）、网络配置文件网关配置，可能是网关配错了导致：

[root@docker-test101 ~]# vim /etc/sysconfig/network-scripts/ifcfg-ens33 
TYPE=Ethernet
PROXY_METHOD=none
BROWSER_ONLY=no
BOOTPROTO=static
DEFROUTE=yes
IPV4_FAILURE_FATAL=yes
IPV6INIT=yes
IPV6_AUTOCONF=yes
IPV6_DEFROUTE=yes
IPV6_FAILURE_FATAL=no
IPV6_ADDR_GEN_MODE=stable-privacy
NAME=ens33
UUID=b7eb8914-c8e6-4546-9bc7-abdfefd11fa9
DEVICE=ens33
ONBOOT=yes
IPADDR=192.168.88.101
PREFIX=24
GATEWAY=192.168.88.2
DNS1=114.114.114.114
DNS2=114.114.114.115
IPV6_PRIVACY=no

总结：
所以遇到这种报错要从这两方面检查，DNS配置是否正确，网关配置是否正确。