centos 7 安装报错：One of the configured repositories failed (unKnown) 解决办法

报错分析

1、错误提示一：（虚假原因）

One of the configured repositories failed (Unknown),and yum doesn’t have enough cached data to continue.
（其中一个已配置的存储库失败（未知），并且yum没有足够的缓存数据可以继续。）

2、错误提示二：（真实原因）（出问题的根本）

Cannot retrieve metalink for repository: epel/x86_64. Please verify its path and try again
（无法检索存储库的metalink：epel / x86_64。 请验证其路径，然后重试）

完整错误：

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
Cannot retrieve metalink for repository: epel/x86_64. Please verify its path and try again

解决办法

步骤一：（备份）

备份需要修改的两个文件
（当然最好备份整个yum.repos.d路径下的所有文件）

cd /etc/yum.repos.d/
mkdir yum_bak
cp -p .* yum_bak/

步骤二：（修改epel.repo配置文件）

1.管理员方式编辑：

vim /etc/yum.repos.d/epel.repo

2.注释掉所有的metalink开头的行，取消注释baseurl开头的行（这里列举是博主的服务器程序，有多处需要自己去发现，一般三处）：

[epel]
name=Extra Packages for Enterprise Linux 7 - $basearch
baseurl=http://download.fedoraproject.org/pub/epel/7/$basearch
#metalink=https://mirrors.fedoraproject.org/metalink?repo=epel-7&arch=$basearch
failovermethod=priority
enabled=1
gpgcheck=1
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-EPEL-7

[epel-debuginfo]
name=Extra Packages for Enterprise Linux 7 - $basearch - Debug
baseurl=http://download.fedoraproject.org/pub/epel/7/$basearch/debug
#metalink=https://mirrors.fedoraproject.org/metalink?repo=epel-debug-7&arch=$basearch
failovermethod=priority
enabled=0
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-EPEL-7
gpgcheck=1

[epel-source]
name=Extra Packages for Enterprise Linux 7 - $basearch - Source
baseurl=http://download.fedoraproject.org/pub/epel/7/SRPMS
#metalink=https://mirrors.fedoraproject.org/metalink?repo=epel-source-7&arch=$basearch
failovermethod=priority
enabled=0
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-EPEL-7
gpgcheck=1

步骤三 ：（修改CentOS-Base.repo配置文件）
1.管理员方式编辑：

vim /etc/yum.repos.d/CentOS-Base.repo

2.注释掉所有的mirrorlist开头的行，取消注释baseurl开头的行（这里列举是博主的服务器程序，有多处需要自己去发现，，一般四处）：

# CentOS-Base.repo
#
# The mirror system uses the connecting IP address of the client and the
# update status of each mirror to pick mirrors that are updated to and
# geographically close to the client.  You should use this for CentOS updates
# unless you are manually picking other mirrors.
#
# If the mirrorlist= does not work for you, as a fall back you can try the
# remarked out baseurl= line instead.
#
#

[base]
name=CentOS-$releasever - Base
#mirrorlist=http://mirrorlist.centos.org/?release=$releasever&arch=$basearch&repo=os
baseurl=http://mirror.centos.org/centos/$releasever/os/$basearch/
gpgcheck=1
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-7

#released updates
[updates]
name=CentOS-$releasever - Updates
#mirrorlist=http://mirrorlist.centos.org/?release=$releasever&arch=$basearch&repo=updates
baseurl=http://mirror.centos.org/centos/$releasever/updates/$basearch/
gpgcheck=1
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-7

#additional packages that may be useful
[extras]
name=CentOS-$releasever - Extras
#mirrorlist=http://mirrorlist.centos.org/?release=$releasever&arch=$basearch&repo=extras
baseurl=http://mirror.centos.org/centos/$releasever/extras/$basearch/
gpgcheck=1
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-7

#additional packages that extend functionality of existing packages
[centosplus]
name=CentOS-$releasever - Plus
#mirrorlist=http://mirrorlist.centos.org/?release=$releasever&arch=$basearch&repo=centosplus
baseurl=http://mirror.centos.org/centos/$releasever/centosplus/$basearch/
gpgcheck=1
enabled=0
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-7

步骤四 ：（清除缓存等，更新yum源）

yum clean all
yum makecache
yum update

然后重新安装即可！