yum install 安装时报yum doesn't have enough cached data to continue.

安装epel，yum -y install epel-release后，yum安装时出现如下异常：

[root@ec-cache ~]# yum install gcc已加载插件：fastestmirrorbase                                                                                                                                                      | 3.6 kB  00:00:00 One of the configured repositories failed (未知), 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 
    
          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=
     
      .skip_if_unavailable=trueCannot retrieve metalink for repository: epel/x86_64. Please verify its path and try again
     
    

解决办法：

[root@ec-cache ~]# /usr/bin/vi /etc/yum.repos.d/epel.repo[epel]name=Extra Packages for Enterprise Linux 7 - $basearchbaseurl=http://download.fedoraproject.org/pub/epel/7/$basearch#mirrorlist=https://mirrors.fedoraproject.org/metalink?repo=epel-7&arch=$basearchfailovermethod=priorityenabled=1gpgcheck=1gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-EPEL-7[epel-debuginfo]name=Extra Packages for Enterprise Linux 7 - $basearch - Debugbaseurl=http://download.fedoraproject.org/pub/epel/7/$basearch/debug#mirrorlist=https://mirrors.fedoraproject.org/metalink?repo=epel-debug-7&arch=$basearchfailovermethod=priorityenabled=0gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-EPEL-7gpgcheck=1[epel-source]name=Extra Packages for Enterprise Linux 7 - $basearch - Sourcebaseurl=http://download.fedoraproject.org/pub/epel/7/SRPMS#mirrorlist=https://mirrors.fedoraproject.org/metalink?repo=epel-source-7&arch=$basearchfailovermethod=priorityenabled=0gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-EPEL-7gpgcheck=1

2、/etc/resolv.conf文件中增加nameserver 144.144.144.144

[root@ec-cache ~]# vi /etc/resolv.conf# Generated by NetworkManagernameserver 192.168.1.2nameserver 144.144.144.144

3、再次执行即可