centos6软件源报错 yum 报错 解决方法 (含epel)
CentOS 6已经随着2020年11月的结束进入了EOL（Reaches End of Life），  
官方便在12月2日正式将CentOS 6相关的软件源移出了官方源，随之而来逐级镜像也会陆续将其删除。  不过有一些老设备依然需要维持在当前系统，CentOS官方也给这些还不想把CentOS 6扔进垃圾堆的用户保留了各个版本软件源的镜像，只是这个软件源不会再有更新了。
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一键修复(阿里云Vault镜像(国内服务器用))
sed -i "s|enabled=1|enabled=0|g" /etc/yum/pluginconf.d/fastestmirror.conf
mv /etc/yum.repos.d/CentOS-Base.repo /etc/yum.repos.d/CentOS-Base.repo.backup
curl -o /etc/yum.repos.d/CentOS-Base.repo https://www.xmpan.com/Centos-6-Vault-Aliyun.repo 
yum clean all
yum makecache
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一键修复(官方Vault源(海外服务器用))
sed -i "s|enabled=1|enabled=0|g" /etc/yum/pluginconf.d/fastestmirror.conf
mv /etc/yum.repos.d/CentOS-Base.repo /etc/yum.repos.d/CentOS-Base.repo.backup
curl -o /etc/yum.repos.d/CentOS-Base.repo https://www.xmpan.com/Centos-6-Vault-Aliyun.repo 
yum clean all
yum makecache
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yum makecache 如果报错:(报错信息如下)是因为之前安装了epel的软件源(yum -y install epel-release)
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已加载插件：refresh-packagekit, security
base                                                                           | 3.7 kB     00:00     
base/group_gz                                                                  | 242 kB     00:00     
base/filelists_db                                                              | 6.4 MB     00:00     
base/primary_db                                                                | 4.7 MB     00:00     
base/other_db                                                                  | 2.8 MB     00:00     
http://mirrors.aliyun.com/epel/6/x86_64/repodata/repomd.xml: [Errno 14] PYCURL ERROR 22 - "The requested URL returned error: 404 Not Found"
尝试其他镜像。
To address this issue please refer to the below knowledge base article 

https://access.redhat.com/articles/1320623

If above article doesn't help to resolve this issue please open a ticket with Red Hat Support.

错误：Cannot retrieve repository metadata (repomd.xml) for repository: epel. Please verify its path and try again
******************************方法一****************************************************
vi /etc/yum.repos.d/epel.repo
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修改前
[epel]
name=Extra Packages for Enterprise Linux 6 - $basearch
baseurl=http://mirrors.aliyun.com/epel/6/$basearch
failovermethod=priority
enabled=1
gpgcheck=0
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-EPEL-6

[epel-debuginfo]
name=Extra Packages for Enterprise Linux 6 - $basearch - Debug
baseurl=http://mirrors.aliyun.com/epel/6/$basearch/debug
failovermethod=priority
enabled=0
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-EPEL-6
gpgcheck=0

[epel-source]
name=Extra Packages for Enterprise Linux 6 - $basearch - Source
baseurl=http://mirrors.aliyun.com/epel/6/SRPMS
failovermethod=priority
enabled=0
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-EPEL-6
gpgcheck=0
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修改后
[epel]
name=Extra Packages for Enterprise Linux 6 - $basearch
baseurl=http://archives.fedoraproject.org/pub/archive/epel/6/$basearch
failovermethod=priority
enabled=1
gpgcheck=1
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-EPEL-6

[epel-debuginfo]
name=Extra Packages for Enterprise Linux 6 - $basearch - Debug
baseurl=http://archives.fedoraproject.org/pub/archive/epel/6/$basearch/debug
failovermethod=priority
enabled=0
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-EPEL-6
gpgcheck=1

[epel-source]
name=Extra Packages for Enterprise Linux 6 - $basearch - Source
baseurl=http://archives.fedoraproject.org/pub/archive/epel/6/SRPMS
failovermethod=priority
enabled=0
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-EPEL-6
gpgcheck=1
******************************说明*******************************************************
正常的/etc/yum.repos.d/epel.repo内容如下
[epel]
name=Extra Packages for Enterprise Linux 6 - $basearch
baseurl=https://archives.fedoraproject.org/pub/archive/epel/6/$basearch
failovermethod=priority
enabled=1
gpgcheck=1
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-EPEL-6

[epel-debuginfo]
name=Extra Packages for Enterprise Linux 6 - $basearch - Debug
baseurl=https://archives.fedoraproject.org/pub/archive/epel/6/$basearch/debug
failovermethod=priority
enabled=0
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-EPEL-6
gpgcheck=1

[epel-source]
name=Extra Packages for Enterprise Linux 6 - $basearch - Source
baseurl=https://archives.fedoraproject.org/pub/archive/epel/6/SRPMS
failovermethod=priority
enabled=0
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-EPEL-6
gpgcheck=1
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如果用https会报错:https://archives.fedoraproject.org/pub/archive/epel/6/x86_64/repodata/repomd.xml: [Errno 14] problem making ssl connection
没有找到解决办法,所以改成http成功了
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******************************方法二****************************************************
vi /etc/yum.repos.d/epel.repo
将项[xxx]（注意：中括号的项有好几个，注意都要改）中的enabled=1改为enabled=0
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修改前
[epel]
name=Extra Packages for Enterprise Linux 6 - $basearch
baseurl=http://mirrors.aliyun.com/epel/6/$basearch
failovermethod=priority
enabled=1
gpgcheck=0
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-EPEL-6

[epel-debuginfo]
name=Extra Packages for Enterprise Linux 6 - $basearch - Debug
baseurl=http://mirrors.aliyun.com/epel/6/$basearch/debug
failovermethod=priority
enabled=0
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-EPEL-6
gpgcheck=0

[epel-source]
name=Extra Packages for Enterprise Linux 6 - $basearch - Source
baseurl=http://mirrors.aliyun.com/epel/6/SRPMS
failovermethod=priority
enabled=0
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-EPEL-6
gpgcheck=0
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修改后
[epel]
name=Extra Packages for Enterprise Linux 6 - $basearch
baseurl=http://mirrors.aliyun.com/epel/6/$basearch
failovermethod=priority
enabled=0
gpgcheck=0
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-EPEL-6

[epel-debuginfo]
name=Extra Packages for Enterprise Linux 6 - $basearch - Debug
baseurl=http://mirrors.aliyun.com/epel/6/$basearch/debug
failovermethod=priority
enabled=0
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-EPEL-6
gpgcheck=0

[epel-source]
name=Extra Packages for Enterprise Linux 6 - $basearch - Source
baseurl=http://mirrors.aliyun.com/epel/6/SRPMS
failovermethod=priority
enabled=0
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-EPEL-6
gpgcheck=0
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yum clean all
yum makecache
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配置epel阿里源如下(有很多不能直接yum的软件,例如:filezilla iftop nginx 如果想yum安装这些软件参考上面的方法一,但方法用的国外网址速度慢)
mv /etc/yum.repos.d/epel.repo /etc/yum.repos.d/epel.repobak
wget -O /etc/yum.repos.d/epel.repo http://mirrors.aliyun.com/repo/epel-6.repo
yum clean all
yum makecache
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