配置 CentOS 的 yum

配置 CentOS 的 DNS：

	vi   /etc/resolv.conf
	nameserver   114.114.114.114

下载 yum 文件，替代原始 yum 源 (以下二选一)：

1. 阿里云 yum 源：

	wget -O /etc/yum.repos.d/CentOS-Aliyun.repo http://mirrors.aliyun.com/repo/Centos-7.repo
	yum clean all
	yum makecache

2. 网易 yum 源：

	wget -O /etc/yum.repos.d/CentOS-163.repo http://mirrors.163.com/.help/CentOS7-Base-163.repo
	yum clean all 
	yum makecache 

解析:

• wget使用 “-o” 参数来指定一个文件名

3. 配置 ELEP 源：

   yum -y install epel-release
   yum clean all
   yum makecache

One of the configured repositories failed 问题

问题：

 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=<repoid> ...

     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

处理：

删除无用的 repo