使用yum按照程序报错如下：

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. 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 <repoid>     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=<repoid>.skip_if_unavailable=true

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网上找了很多办法都没有解决，困扰一天，第二天继续处理，使用以下命令解决问题，仅此记录！！

执行下面几个命令：

yum clean all
yum makecache
yum update yum install -y lsof