Centos7默认的YUM源都是海外的服务器的，国内访问缓慢或者干脆无法访问，为了能正常使用，换源是必须的，同时为了保证软件的丰富性，添加EPEL扩展源会减少很多不必要的麻烦。
下面给Centos7换腾讯云的YUM源和EPEL扩展源，腾讯云的比阿里云的源快。
1.备份原来的YUM源：
mv /etc/yum.repos.d/CentOS-Base.repo /etc/yum.repos.d/CentOS-Base.repo.backup mv /etc/yum.repos.d/CentOS-CR.repo /etc/yum.repos.d/CentOS-CR.repo.backup mv /etc/yum.repos.d/CentOS-Debuginfo.repo /etc/yum.repos.d/CentOS-Debuginfo.repo.backup mv /etc/yum.repos.d/CentOS-fasttrack.repo /etc/yum.repos.d/CentOS-fasttrack.repo.backup mv /etc/yum.repos.d/CentOS-Media.repo /etc/yum.repos.d/CentOS-Media.repo.backup mv /etc/yum.repos.d/CentOS-Sources.repo /etc/yum.repos.d/CentOS-Sources.repo.backup mv /etc/yum.repos.d/CentOS-Vault.repo /etc/yum.repos.d/CentOS-Vault.repo.backup mv /etc/yum.repos.d/CentOS-x86_64-kernel.repo /etc/yum.repos.d/CentOS-x86_64-kernel.repo.backup
2.创建EPEL扩展源文件：
touch epel.repo touch epel-testing.repo
3.替换腾讯云的YUM源和EPEL扩展源：
cat > /etc/yum.repos.d/CentOS-Base.repo <<'EOF'
# 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=$basearch&repo=os&infra=$infra
baseurl=http://mirrors.cloud.tencent.com/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=$basearch&repo=updates&infra=$infra
baseurl=http://mirrors.cloud.tencent.com/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=$basearch&repo=extras&infra=$infra
baseurl=http://mirrors.cloud.tencent.com/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=$basearch&repo=centosplus&infra=$infra
baseurl=http://mirrors.cloud.tencent.com/centos/$releasever/centosplus/$basearch/
gpgcheck=1
enabled=0
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-7
EOF
cat > /etc/yum.repos.d/CentOS-CR.repo <<'EOF'
# CentOS-CR.repo
#
# The Continuous Release ( CR ) repository contains rpms that are due in the next
# release for a specific CentOS Version ( eg. next release in CentOS-7 ); these rpms
# are far less tested, with no integration checking or update path testing having
# taken place. They are still built from the upstream sources, but might not map
# to an exact upstream distro release.
#
# These packages are made available soon after they are built, for people willing
# to test their environments, provide feedback on content for the next release, and
# for people looking for early-access to next release content.
#
# The CR repo is shipped in a disabled state by default; its important that users
# understand the implications of turning this on.
#
# NOTE: We do not use a mirrorlist for the CR repos, to ensure content is available
# to everyone as soon as possible, and not need to wait for the external
# mirror network to seed first. However, many local mirrors will carry CR repos
# and if desired you can use one of these local mirrors by editing the baseurl
# line in the repo config below.
#
[cr]
name=CentOS-$releasever - cr
baseurl=http://mirrors.cloud.tencent.com/centos/$releasever/cr/$basearch/
gpgcheck=1
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-7
enabled=0
EOF
cat > /etc/yum.repos.d/CentOS-Debuginfo.repo <<'EOF'
# CentOS-Debug.repo
#
# The mirror system uses the connecting IP address of the client and the
# update status of each mirror to pick mirrors that are updated to and
# geographically close to the client. You should use this for CentOS updates
# unless you are manually picking other mirrors.
#
# All debug packages from all the various CentOS-7 releases
# are merged into a single repo, split by BaseArch
#
# Note: packages in the debuginfo repo are currently not signed
#
[base-debuginfo]
name=CentOS-7 - Debuginfo
baseurl=http://debuginfo.centos.org/7/$basearch/
gpgcheck=1
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-Debug-7
enabled=0
#
EOF
cat > /etc/yum.repos.d/CentOS-fasttrack.repo <<'EOF'
[fasttrack]
name=CentOS-7 - fasttrack
#mirrorlist=http://mirrorlist.centos.org/?release=$releasever&arch=$basearch&repo=fasttrack&infra=$infra
baseurl=http://mirrors.cloud.tencent.com/centos/$releasever/fasttrack/$basearch/
gpgcheck=1
enabled=0
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-7
EOF
cat > /etc/yum.repos.d/CentOS-Media.repo <<'EOF'
# CentOS-Media.repo
#
# This repo can be used with mounted DVD media, verify the mount point for
# CentOS-7. You can use this repo and yum to install items directly off the
# DVD ISO that we release.
#
# To use this repo, put in your DVD and use it with the other repos too:
# yum --enablerepo=c7-media [command]
#
# or for ONLY the media repo, do this:
#
# yum --disablerepo=\* --enablerepo=c7-media [command]
[c7-media]
name=CentOS-$releasever - Media
baseurl=file:///media/CentOS/
file:///media/cdrom/
file:///media/cdrecorder/
gpgcheck=1
enabled=0
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-7
EOF
cat > /etc/yum.repos.d/CentOS-Sources.repo <<'EOF'
# CentOS-Sources.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-source]
name=CentOS-$releasever - Base Sources
baseurl=http://vault.centos.org/centos/$releasever/os/Source/
gpgcheck=1
enabled=0
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-7
#released updates
[updates-source]
name=CentOS-$releasever - Updates Sources
baseurl=http://vault.centos.org/centos/$releasever/updates/Source/
gpgcheck=1
enabled=0
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-7
#additional packages that may be useful
[extras-source]
name=CentOS-$releasever - Extras Sources
baseurl=http://vault.centos.org/centos/$releasever/extras/Source/
gpgcheck=1
enabled=0
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-7
#additional packages that extend functionality of existing packages
[centosplus-source]
name=CentOS-$releasever - Plus Sources
baseurl=http://vault.centos.org/centos/$releasever/centosplus/Source/
gpgcheck=1
enabled=0
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-7
EOF
cat > /etc/yum.repos.d/CentOS-Vault.repo <<'EOF'
# CentOS Vault contains rpms from older releases in the CentOS-7
# tree.
# C7.0.1406
[C7.0.1406-base]
name=CentOS-7.0.1406 - Base
baseurl=http://vault.centos.org/7.0.1406/os/$basearch/
gpgcheck=1
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-7
enabled=0
[C7.0.1406-updates]
name=CentOS-7.0.1406 - Updates
baseurl=http://vault.centos.org/7.0.1406/updates/$basearch/
gpgcheck=1
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-7
enabled=0
[C7.0.1406-extras]
name=CentOS-7.0.1406 - Extras
baseurl=http://vault.centos.org/7.0.1406/extras/$basearch/
gpgcheck=1
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-7
enabled=0
[C7.0.1406-centosplus]
name=CentOS-7.0.1406 - CentOSPlus
baseurl=http://vault.centos.org/7.0.1406/centosplus/$basearch/
gpgcheck=1
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-7
enabled=0
[C7.0.1406-fasttrack]
name=CentOS-7.0.1406 - Fasttrack
baseurl=http://vault.centos.org/7.0.1406/fasttrack/$basearch/
gpgcheck=1
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-7
enabled=0
# C7.1.1503
[C7.1.1503-base]
name=CentOS-7.1.1503 - Base
baseurl=http://vault.centos.org/7.1.1503/os/$basearch/
gpgcheck=1
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-7
enabled=0
[C7.1.1503-updates]
name=CentOS-7.1.1503 - Updates
baseurl=http://vault.centos.org/7.1.1503/updates/$basearch/
gpgcheck=1
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-7
enabled=0
[C7.1.1503-extras]
name=CentOS-7.1.1503 - Extras
baseurl=http://vault.centos.org/7.1.1503/extras/$basearch/
gpgcheck=1
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-7
enabled=0
[C7.1.1503-centosplus]
name=CentOS-7.1.1503 - CentOSPlus
baseurl=http://vault.centos.org/7.1.1503/centosplus/$basearch/
gpgcheck=1
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-7
enabled=0
[C7.1.1503-fasttrack]
name=CentOS-7.1.1503 - Fasttrack
baseurl=http://vault.centos.org/7.1.1503/fasttrack/$basearch/
gpgcheck=1
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-7
enabled=0
# C7.2.1511
[C7.2.1511-base]
name=CentOS-7.2.1511 - Base
baseurl=http://vault.centos.org/7.2.1511/os/$basearch/
gpgcheck=1
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-7
enabled=0
[C7.2.1511-updates]
name=CentOS-7.2.1511 - Updates
baseurl=http://vault.centos.org/7.2.1511/updates/$basearch/
gpgcheck=1
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-7
enabled=0
[C7.2.1511-extras]
name=CentOS-7.2.1511 - Extras
baseurl=http://vault.centos.org/7.2.1511/extras/$basearch/
gpgcheck=1
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-7
enabled=0
[C7.2.1511-centosplus]
name=CentOS-7.2.1511 - CentOSPlus
baseurl=http://vault.centos.org/7.2.1511/centosplus/$basearch/
gpgcheck=1
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-7
enabled=0
[C7.2.1511-fasttrack]
name=CentOS-7.2.1511 - Fasttrack
baseurl=http://vault.centos.org/7.2.1511/fasttrack/$basearch/
gpgcheck=1
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-7
enabled=0
# C7.3.1611
[C7.3.1611-base]
name=CentOS-7.3.1611 - Base
baseurl=http://vault.centos.org/7.3.1611/os/$basearch/
gpgcheck=1
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-7
enabled=0
[C7.3.1611-updates]
name=CentOS-7.3.1611 - Updates
baseurl=http://vault.centos.org/7.3.1611/updates/$basearch/
gpgcheck=1
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-7
enabled=0
[C7.3.1611-extras]
name=CentOS-7.3.1611 - Extras
baseurl=http://vault.centos.org/7.3.1611/extras/$basearch/
gpgcheck=1
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-7
enabled=0
[C7.3.1611-centosplus]
name=CentOS-7.3.1611 - CentOSPlus
baseurl=http://vault.centos.org/7.3.1611/centosplus/$basearch/
gpgcheck=1
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-7
enabled=0
[C7.3.1611-fasttrack]
name=CentOS-7.3.1611 - Fasttrack
baseurl=http://vault.centos.org/7.3.1611/fasttrack/$basearch/
gpgcheck=1
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-7
enabled=0
# C7.4.1708
[C7.4.1708-base]
name=CentOS-7.4.1708 - Base
baseurl=http://vault.centos.org/7.4.1708/os/$basearch/
gpgcheck=1
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-7
enabled=0
[C7.4.1708-updates]
name=CentOS-7.4.1708 - Updates
baseurl=http://vault.centos.org/7.4.1708/updates/$basearch/
gpgcheck=1
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-7
enabled=0
[C7.4.1708-extras]
name=CentOS-7.4.1708 - Extras
baseurl=http://vault.centos.org/7.4.1708/extras/$basearch/
gpgcheck=1
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-7
enabled=0
[C7.4.1708-centosplus]
name=CentOS-7.4.1708 - CentOSPlus
baseurl=http://vault.centos.org/7.4.1708/centosplus/$basearch/
gpgcheck=1
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-7
enabled=0
[C7.4.1708-fasttrack]
name=CentOS-7.4.1708 - Fasttrack
baseurl=http://vault.centos.org/7.4.1708/fasttrack/$basearch/
gpgcheck=1
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-7
enabled=0
# C7.5.1804
[C7.5.1804-base]
name=CentOS-7.5.1804 - Base
baseurl=http://vault.centos.org/7.5.1804/os/$basearch/
gpgcheck=1
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-7
enabled=0
[C7.5.1804-updates]
name=CentOS-7.5.1804 - Updates
baseurl=http://vault.centos.org/7.5.1804/updates/$basearch/
gpgcheck=1
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-7
enabled=0
[C7.5.1804-extras]
name=CentOS-7.5.1804 - Extras
baseurl=http://vault.centos.org/7.5.1804/extras/$basearch/
gpgcheck=1
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-7
enabled=0
[C7.5.1804-centosplus]
name=CentOS-7.5.1804 - CentOSPlus
baseurl=http://vault.centos.org/7.5.1804/centosplus/$basearch/
gpgcheck=1
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-7
enabled=0
[C7.5.1804-fasttrack]
name=CentOS-7.5.1804 - Fasttrack
baseurl=http://vault.centos.org/7.5.1804/fasttrack/$basearch/
gpgcheck=1
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-7
enabled=0
# C7.6.1810
[C7.6.1810-base]
name=CentOS-7.6.1810 - Base
baseurl=http://vault.centos.org/7.6.1810/os/$basearch/
gpgcheck=1
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-7
enabled=0
[C7.6.1810-updates]
name=CentOS-7.6.1810 - Updates
baseurl=http://vault.centos.org/7.6.1810/updates/$basearch/
gpgcheck=1
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-7
enabled=0
[C7.6.1810-extras]
name=CentOS-7.6.1810 - Extras
baseurl=http://vault.centos.org/7.6.1810/extras/$basearch/
gpgcheck=1
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-7
enabled=0
[C7.6.1810-centosplus]
name=CentOS-7.6.1810 - CentOSPlus
baseurl=http://vault.centos.org/7.6.1810/centosplus/$basearch/
gpgcheck=1
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-7
enabled=0
[C7.6.1810-fasttrack]
name=CentOS-7.6.1810 - Fasttrack
baseurl=http://vault.centos.org/7.6.1810/fasttrack/$basearch/
gpgcheck=1
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-7
enabled=0
# C7.7.1908
[C7.7.1908-base]
name=CentOS-7.7.1908 - Base
baseurl=http://vault.centos.org/7.7.1908/os/$basearch/
gpgcheck=1
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-7
enabled=0
[C7.7.1908-updates]
name=CentOS-7.7.1908 - Updates
baseurl=http://vault.centos.org/7.7.1908/updates/$basearch/
gpgcheck=1
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-7
enabled=0
[C7.7.1908-extras]
name=CentOS-7.7.1908 - Extras
baseurl=http://vault.centos.org/7.7.1908/extras/$basearch/
gpgcheck=1
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-7
enabled=0
[C7.7.1908-centosplus]
name=CentOS-7.7.1908 - CentOSPlus
baseurl=http://vault.centos.org/7.7.1908/centosplus/$basearch/
gpgcheck=1
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-7
enabled=0
[C7.7.1908-fasttrack]
name=CentOS-7.7.1908 - Fasttrack
baseurl=http://vault.centos.org/7.7.1908/fasttrack/$basearch/
gpgcheck=1
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-7
enabled=0
# C7.8.2003
[C7.8.2003-base]
name=CentOS-7.8.2003 - Base
baseurl=http://vault.centos.org/7.8.2003/os/$basearch/
gpgcheck=1
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-7
enabled=0
[C7.8.2003-updates]
name=CentOS-7.8.2003 - Updates
baseurl=http://vault.centos.org/7.8.2003/updates/$basearch/
gpgcheck=1
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-7
enabled=0
[C7.8.2003-extras]
name=CentOS-7.8.2003 - Extras
baseurl=http://vault.centos.org/7.8.2003/extras/$basearch/
gpgcheck=1
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-7
enabled=0
[C7.8.2003-centosplus]
name=CentOS-7.8.2003 - CentOSPlus
baseurl=http://vault.centos.org/7.8.2003/centosplus/$basearch/
gpgcheck=1
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-7
enabled=0
[C7.8.2003-fasttrack]
name=CentOS-7.8.2003 - Fasttrack
baseurl=http://vault.centos.org/7.8.2003/fasttrack/$basearch/
gpgcheck=1
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-7
enabled=0
EOF
cat > /etc/yum.repos.d/CentOS-x86_64-kernel.repo <<'EOF'
[centos-kernel]
name=CentOS LTS Kernels for $basearch
mirrorlist=http://mirrorlist.centos.org/?release=$releasever&arch=$basearch&repo=kernel&infra=$infra
#baseurl=http://mirror.centos.org/altarch/7/kernel/$basearch/
enabled=0
gpgcheck=1
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-7
[centos-kernel-experimental]
name=CentOS Experimental Kernels for $basearch
mirrorlist=http://mirrorlist.centos.org/?release=$releasever&arch=$basearch&repo=experimental&infra=$infra
#baseurl=http://mirror.centos.org/altarch/7/experimental/$basearch/
enabled=0
gpgcheck=1
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-7
EOF
cat > /etc/yum.repos.d/epel.repo <<'EOF'
[epel]
name=Extra Packages for Enterprise Linux 7 - $basearch
baseurl=http://mirrors.cloud.tencent.com/epel/7/$basearch
#metalink=https://mirrors.fedoraproject.org/metalink?repo=epel-7&arch=$basearch
failovermethod=priority
enabled=1
gpgcheck=0
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-EPEL-7
[epel-debuginfo]
name=Extra Packages for Enterprise Linux 7 - $basearch - Debug
baseurl=http://mirrors.cloud.tencent.com/epel/7/$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=0
[epel-source]
name=Extra Packages for Enterprise Linux 7 - $basearch - Source
baseurl=http://mirrors.cloud.tencent.com/epel/7/SRPMS
#metalink=https://mirrors.fedoraproject.org/metalink?repo=epel-source-7&arch=$basearch
failovermethod=priority
enabled=0
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-EPEL-7
gpgcheck=0
EOF
cat > /etc/yum.repos.d/epel-testing.repo <<'EOF'
[epel-testing]
name=Extra Packages for Enterprise Linux 7 - Testing - $basearch
baseurl=http://mirrors.cloud.tencent.com/epel/testing/7/$basearch
#metalink=https://mirrors.fedoraproject.org/metalink?repo=testing-epel7&arch=$basearch
failovermethod=priority
enabled=0
gpgcheck=0
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-EPEL-7
[epel-testing-debuginfo]
name=Extra Packages for Enterprise Linux 7 - Testing - $basearch - Debug
baseurl=http://mirrors.cloud.tencent.com/epel/testing/7/$basearch/debug
#metalink=https://mirrors.fedoraproject.org/metalink?repo=testing-debug-epel7&arch=$basearch
failovermethod=priority
enabled=0
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-EPEL-7
gpgcheck=0
[epel-testing-source]
name=Extra Packages for Enterprise Linux 7 - Testing - $basearch - Source
baseurl=http://mirrors.cloud.tencent.com/epel/testing/7/SRPMS
#metalink=https://mirrors.fedoraproject.org/metalink?repo=testing-source-epel7&arch=$basearch
failovermethod=priority
enabled=0
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-EPEL-7
gpgcheck=0
EOF
4.清理老的YUM源缓存并重新生成YUM源和EPEL源的缓存：
yum clean all yum makecache
5.安装常用软件工具：
#安装Wget yum install -y wget #安装vim yum install -y vim #安装net-tools yum install -y net-tools #安装gcc yum -y install gcc make #安装自动补全命令工具bash-completion yum -y install bash-completion #杀死僵尸进程工具psmisc yum -y install psmisc
6.完成
还有一键换源脚本：
bash <(curl -sSL https://gitee.com/SuperManito/LinuxMirrors/raw/main/ChangeMirrors.sh)
上文中第三步其实也可以直通上传替换到的文件来实现。