0.域名无法解析

vi /etc/resolv.conf
nameserver 8.8.8.8
nameserver 114.114.114.114

1.备份原先yum源

cd /etc/yum.repos.d
mv /etc/yum.repos.d/CentOS-Base.repo /etc/yum.repos.d/CentOS-Base.repo.copy
mv /etc/yum.repos.d/CentOS-Base.repo.backup /etc/yum.repos.d/CentOS-Base.repo.backup.copy
mv /etc/yum.repos.d/CentOS-Debuginfo.repo /etc/yum.repos.d/CentOS-Debuginfo.repo.copy
mv /etc/yum.repos.d/CentOS-fasttrack.repo /etc/yum.repos.d/CentOS-fasttrack.repo.copy
mv /etc/yum.repos.d/CentOS-Media.repo /etc/yum.repos.d/CentOS-Media.repo.copy
mv /etc/yum.repos.d/CentOS-Vault.repo /etc/yum.repos.d/CentOS-Vault.repo.copy
mv /etc/yum.repos.d/epel.repo /etc/yum.repos.d/epel.repo.copy
mv /etc/yum.repos.d/epel-testing.repo /etc/yum.repos.d/epel-testing.repo.copy

2.写入新的yum源

echo '[base]
name=CentOS-6.10 - Base - mirrors.aliyun.com
failovermethod=priority
baseurl=http://mirrors.aliyun.com/centos-vault/6.10/os/$basearch/
gpgcheck=1
gpgkey=http://mirrors.aliyun.com/centos-vault/RPM-GPG-KEY-CentOS-6
 
#released updates 
[updates]
name=CentOS-6.10 - Updates - mirrors.aliyun.com
failovermethod=priority
baseurl=http://mirrors.aliyun.com/centos-vault/6.10/updates/$basearch/
gpgcheck=1
gpgkey=http://mirrors.aliyun.com/centos-vault/RPM-GPG-KEY-CentOS-6
 
#additional packages that may be useful
[extras]
name=CentOS-6.10 - Extras - mirrors.aliyun.com
failovermethod=priority
baseurl=http://mirrors.aliyun.com/centos-vault/6.10/extras/$basearch/
gpgcheck=1
gpgkey=http://mirrors.aliyun.com/centos-vault/RPM-GPG-KEY-CentOS-6
 
#additional packages that extend functionality of existing packages
[centosplus]
name=CentOS-6.10 - Plus - mirrors.aliyun.com
failovermethod=priority
baseurl=http://mirrors.aliyun.com/centos-vault/6.10/centosplus/$basearch/
gpgcheck=1
enabled=0
gpgkey=http://mirrors.aliyun.com/centos-vault/RPM-GPG-KEY-CentOS-6
 
#contrib - packages by Centos Users
[contrib]
name=CentOS-6.10 - Contrib - mirrors.aliyun.com
failovermethod=priority
baseurl=http://mirrors.aliyun.com/centos-vault/6.10/contrib/$basearch/
gpgcheck=1
enabled=0
gpgkey=http://mirrors.aliyun.com/centos-vault/RPM-GPG-KEY-CentOS-6' > /etc/yum.repos.d/CentOS-Base.repo



echo '[base]
name=CentOS-6.10 - Base - mirrors.aliyun.com
failovermethod=priority
baseurl=http://mirrors.aliyun.com/centos-vault/6.10/os/$basearch/
gpgcheck=1
gpgkey=http://mirrors.aliyun.com/centos-vault/RPM-GPG-KEY-CentOS-6
 
#released updates 
[updates]
name=CentOS-6.10 - Updates - mirrors.aliyun.com
failovermethod=priority
baseurl=http://mirrors.aliyun.com/centos-vault/6.10/updates/$basearch/
gpgcheck=1
gpgkey=http://mirrors.aliyun.com/centos-vault/RPM-GPG-KEY-CentOS-6
 
#additional packages that may be useful
[extras]
name=CentOS-6.10 - Extras - mirrors.aliyun.com
failovermethod=priority
baseurl=http://mirrors.aliyun.com/centos-vault/6.10/extras/$basearch/
gpgcheck=1
gpgkey=http://mirrors.aliyun.com/centos-vault/RPM-GPG-KEY-CentOS-6
 
#additional packages that extend functionality of existing packages
[centosplus]
name=CentOS-6.10 - Plus - mirrors.aliyun.com
failovermethod=priority
baseurl=http://mirrors.aliyun.com/centos-vault/6.10/centosplus/$basearch/
gpgcheck=1
enabled=0
gpgkey=http://mirrors.aliyun.com/centos-vault/RPM-GPG-KEY-CentOS-6
 
#contrib - packages by Centos Users
[contrib]
name=CentOS-6.10 - Contrib - mirrors.aliyun.com
failovermethod=priority
baseurl=http://mirrors.aliyun.com/centos-vault/6.10/contrib/$basearch/
gpgcheck=1
enabled=0
gpgkey=http://mirrors.aliyun.com/centos-vault/RPM-GPG-KEY-CentOS-6' > /etc/yum.repos.d/CentOS-Base.repo



echo '# 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-5 releases
# are merged into a single repo, split by BaseArch
#
# Note: packages in the debuginfo repo are currently not signed
#

[base-debuginfo]
name=CentOS-6 - Debuginfo
baseurl=http://debuginfo.centos.org/6/$basearch/
gpgcheck=1
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-Debug-6
enabled=0' > /etc/yum.repos.d/CentOS-Debuginfo.repo





echo '[fasttrack]
name=CentOS-6 - fasttrack
mirrorlist=http://mirrorlist.centos.org/?release=$releasever&arch=$basearch&repo=fasttrack&infra=$infra
#baseurl=http://mirror.centos.org/centos/$releasever/fasttrack/$basearch/
gpgcheck=1
enabled=0
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-6' > /etc/yum.repos.d/CentOS-fasttrack.repo




echo '# CentOS-Media.repo
#
#  This repo can be used with mounted DVD media, verify the mount point for
#  CentOS-6.  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=c6-media [command]
#  
# or for ONLY the media repo, do this:
#
#  yum --disablerepo=\* --enablerepo=c6-media [command]
 
[c6-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-6' > /etc/yum.repos.d/CentOS-Media.repo





echo '[epel]
name=Extra Packages for Enterprise Linux 6 - $basearch
#baseurl=http://download.fedoraproject.org/pub/epel/6/$basearch
mirrorlist=https://mirrors.fedoraproject.org/metalink?repo=epel-6&arch=$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 - $basearch - Debug
#baseurl=http://download.fedoraproject.org/pub/epel/6/$basearch/debug
mirrorlist=https://mirrors.fedoraproject.org/metalink?repo=epel-debug-6&arch=$basearch
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 - $basearch - Source
#baseurl=http://download.fedoraproject.org/pub/epel/6/SRPMS
mirrorlist=https://mirrors.fedoraproject.org/metalink?repo=epel-source-6&arch=$basearch
failovermethod=priority
enabled=0
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-EPEL-6
gpgcheck=1' > /etc/yum.repos.d/epel.repo





echo '[epel-testing]
name=Extra Packages for Enterprise Linux 6 - Testing - $basearch
#baseurl=http://download.fedoraproject.org/pub/epel/testing/6/$basearch
mirrorlist=https://mirrors.fedoraproject.org/metalink?repo=testing-epel6&arch=$basearch
failovermethod=priority
enabled=0
gpgcheck=1
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-EPEL-6

[epel-testing-debuginfo]
name=Extra Packages for Enterprise Linux 6 - Testing - $basearch - Debug
#baseurl=http://download.fedoraproject.org/pub/epel/testing/6/$basearch/debug
mirrorlist=https://mirrors.fedoraproject.org/metalink?repo=testing-debug-epel6&arch=$basearch
failovermethod=priority
enabled=0
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-EPEL-6
gpgcheck=1

[epel-testing-source]
name=Extra Packages for Enterprise Linux 6 - Testing - $basearch - Source
#baseurl=http://download.fedoraproject.org/pub/epel/testing/6/SRPMS
mirrorlist=https://mirrors.fedoraproject.org/metalink?repo=testing-source-epel6&arch=$basearch
failovermethod=priority
enabled=0
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-EPEL-6
gpgcheck=1' > /etc/yum.repos.d/epel-testing.repo




echo '# CentOS-Vault.repo
#
# CentOS Vault holds packages from previous releases within the same CentOS Version
# these are packages obsoleted by the current release and should usually not 
# be used in production
#-----------------

[C6.0-base]
name=CentOS-6.0 - Base
baseurl=http://vault.centos.org/6.0/os/$basearch/
gpgcheck=1
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-6
enabled=0

[C6.0-updates]
name=CentOS-6.0 - Updates
baseurl=http://vault.centos.org/6.0/updates/$basearch/
gpgcheck=1
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-6
enabled=0

[C6.0-extras]
name=CentOS-6.0 - Extras
baseurl=http://vault.centos.org/6.0/extras/$basearch/
gpgcheck=1
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-6
enabled=0

[C6.0-contrib]
name=CentOS-6.0 - Contrib
baseurl=http://vault.centos.org/6.0/contrib/$basearch/
gpgcheck=1
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-6
enabled=0

[C6.0-centosplus]
name=CentOS-6.0 - CentOSPlus
baseurl=http://vault.centos.org/6.0/centosplus/$basearch/
gpgcheck=1
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-6
enabled=0
#-----------------

[C6.1-base]
name=CentOS-6.1 - Base
baseurl=http://vault.centos.org/6.1/os/$basearch/
gpgcheck=1
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-6
enabled=0

[C6.1-updates]
name=CentOS-6.1 - Updates
baseurl=http://vault.centos.org/6.1/updates/$basearch/
gpgcheck=1
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-6
enabled=0

[C6.1-extras]
name=CentOS-6.1 - Extras
baseurl=http://vault.centos.org/6.1/extras/$basearch/
gpgcheck=1
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-6
enabled=0

[C6.1-contrib]
name=CentOS-6.1 - Contrib
baseurl=http://vault.centos.org/6.1/contrib/$basearch/
gpgcheck=1
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-6
enabled=0

[C6.1-centosplus]
name=CentOS-6.1 - CentOSPlus
baseurl=http://vault.centos.org/6.1/centosplus/$basearch/
gpgcheck=1
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-6
enabled=0
#-----------------

[C6.2-base]
name=CentOS-6.2 - Base
baseurl=http://vault.centos.org/6.2/os/$basearch/
gpgcheck=1
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-6
enabled=0

[C6.2-updates]
name=CentOS-6.2 - Updates
baseurl=http://vault.centos.org/6.2/updates/$basearch/
gpgcheck=1
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-6
enabled=0

[C6.2-extras]
name=CentOS-6.2 - Extras
baseurl=http://vault.centos.org/6.2/extras/$basearch/
gpgcheck=1
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-6
enabled=0

[C6.2-contrib]
name=CentOS-6.2 - Contrib
baseurl=http://vault.centos.org/6.2/contrib/$basearch/
gpgcheck=1
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-6
enabled=0

[C6.2-centosplus]
name=CentOS-6.2 - CentOSPlus
baseurl=http://vault.centos.org/6.2/centosplus/$basearch/
gpgcheck=1
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-6
enabled=0
#-----------------

[C6.3-base]
name=CentOS-6.3 - Base
baseurl=http://vault.centos.org/6.3/os/$basearch/
gpgcheck=1
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-6
enabled=0

[C6.3-updates]
name=CentOS-6.3 - Updates
baseurl=http://vault.centos.org/6.3/updates/$basearch/
gpgcheck=1
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-6
enabled=0

[C6.3-extras]
name=CentOS-6.3 - Extras
baseurl=http://vault.centos.org/6.3/extras/$basearch/
gpgcheck=1
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-6
enabled=0

[C6.3-contrib]
name=CentOS-6.3 - Contrib
baseurl=http://vault.centos.org/6.3/contrib/$basearch/
gpgcheck=1
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-6
enabled=0

[C6.3-centosplus]
name=CentOS-6.3 - CentOSPlus
baseurl=http://vault.centos.org/6.3/centosplus/$basearch/
gpgcheck=1
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-6
enabled=0
#-----------------

[C6.4-base]
name=CentOS-6.4 - Base
baseurl=http://vault.centos.org/6.4/os/$basearch/
gpgcheck=1
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-6
enabled=0

[C6.4-updates]
name=CentOS-6.4 - Updates
baseurl=http://vault.centos.org/6.4/updates/$basearch/
gpgcheck=1
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-6
enabled=0

[C6.4-extras]
name=CentOS-6.4 - Extras
baseurl=http://vault.centos.org/6.4/extras/$basearch/
gpgcheck=1
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-6
enabled=0

[C6.4-contrib]
name=CentOS-6.4 - Contrib
baseurl=http://vault.centos.org/6.4/contrib/$basearch/
gpgcheck=1
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-6
enabled=0

[C6.4-centosplus]
name=CentOS-6.4 - CentOSPlus
baseurl=http://vault.centos.org/6.4/centosplus/$basearch/
gpgcheck=1
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-6
enabled=0

#-----------------

[C6.5-base]
name=CentOS-6.5 - Base
baseurl=http://vault.centos.org/6.5/os/$basearch/
gpgcheck=1
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-6
enabled=0

[C6.5-updates]
name=CentOS-6.5 - Updates
baseurl=http://vault.centos.org/6.5/updates/$basearch/
gpgcheck=1
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-6
enabled=0

[C6.5-extras]
name=CentOS-6.5 - Extras
baseurl=http://vault.centos.org/6.5/extras/$basearch/
gpgcheck=1
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-6
enabled=0

[C6.5-contrib]
name=CentOS-6.5 - Contrib
baseurl=http://vault.centos.org/6.5/contrib/$basearch/
gpgcheck=1
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-6
enabled=0

[C6.5-centosplus]
name=CentOS-6.5 - CentOSPlus
baseurl=http://vault.centos.org/6.5/centosplus/$basearch/
gpgcheck=1
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-6
enabled=0

#-----------------

[C6.6-base]
name=CentOS-6.6 - Base
baseurl=http://vault.centos.org/6.6/os/$basearch/
gpgcheck=1
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-6
enabled=0

[C6.6-updates]
name=CentOS-6.6 - Updates
baseurl=http://vault.centos.org/6.6/updates/$basearch/
gpgcheck=1
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-6
enabled=0

[C6.6-extras]
name=CentOS-6.6 - Extras
baseurl=http://vault.centos.org/6.6/extras/$basearch/
gpgcheck=1
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-6
enabled=0

[C6.6-contrib]
name=CentOS-6.6 - Contrib
baseurl=http://vault.centos.org/6.6/contrib/$basearch/
gpgcheck=1
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-6
enabled=0

[C6.6-centosplus]
name=CentOS-6.6 - CentOSPlus
baseurl=http://vault.centos.org/6.6/centosplus/$basearch/
gpgcheck=1
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-6
enabled=0

#-----------------

[C6.7-base]
name=CentOS-6.7 - Base
baseurl=http://vault.centos.org/6.7/os/$basearch/
gpgcheck=1
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-6
enabled=0

[C6.7-updates]
name=CentOS-6.7 - Updates
baseurl=http://vault.centos.org/6.7/updates/$basearch/
gpgcheck=1
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-6
enabled=0

[C6.7-extras]
name=CentOS-6.7 - Extras
baseurl=http://vault.centos.org/6.7/extras/$basearch/
gpgcheck=1
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-6
enabled=0

[C6.7-contrib]
name=CentOS-6.7 - Contrib
baseurl=http://vault.centos.org/6.7/contrib/$basearch/
gpgcheck=1
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-6
enabled=0

[C6.7-centosplus]
name=CentOS-6.7 - CentOSPlus
baseurl=http://vault.centos.org/6.7/centosplus/$basearch/
gpgcheck=1
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-6
enabled=0

#-----------------

[C6.8-base]
name=CentOS-6.8 - Base
baseurl=http://vault.centos.org/6.8/os/$basearch/
gpgcheck=1
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-6
enabled=0

[C6.8-updates]
name=CentOS-6.8 - Updates
baseurl=http://vault.centos.org/6.8/updates/$basearch/
gpgcheck=1
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-6
enabled=0

[C6.8-extras]
name=CentOS-6.8 - Extras
baseurl=http://vault.centos.org/6.8/extras/$basearch/
gpgcheck=1
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-6
enabled=0

[C6.8-contrib]
name=CentOS-6.8 - Contrib
baseurl=http://vault.centos.org/6.8/contrib/$basearch/
gpgcheck=1
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-6
enabled=0

[C6.8-centosplus]
name=CentOS-6.8 - CentOSPlus
baseurl=http://vault.centos.org/6.8/centosplus/$basearch/
gpgcheck=1
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-6
enabled=0' > /etc/yum.repos.d/CentOS-Vault.repo