RedHat yum源誤刪除

rpm -aq|grep yum|xargs rpm -e --nodeps 刪除了redhat的yum。
導致yum不可用.用以下方法恢復yum.
1：先徹底清除系統上的yum文件。
2：去http://rpm.pbone.net/index.php3下載以下rpm文件：
1）yum-utils-1.1.31-34.el7.noarch.rpm
2）yum-updateonboot-1.1.31-34.el7.noarch.rpm
3）yum-plugin-fastestmirror-1.1.31-34.el7.noarch.rpm
4）yum-metadata-parser-1.1.4-10.el7.x86_64.rpm
5）yum-3.4.3-132.el7.centos.0.1.noarch.rpm
6）python-kitchen-1.2.4-2.fc24.src.rpm
3：然後逐個安裝。（注意：安裝yum-utils-1.1.31-34.el7.noarch.rpm時會有提示：
warning: user mockbuild does not exist - using root
warning: group mockbuild does not exist - using root
新建一個組和一個帳號就好了
#groupadd mockbuild
#useradd mockbuild -g mockbuild）
4：這時去/etc/yum.repos.d目錄下新增以下repo文件，使用163的yum源：
1）Centos-163.repo

[base]
name=CentOS-7 - Base - 163.com
#mirrorlist=http://mirrorlist.centos.org/?release=7&arch=x86_64&repo=os
baseurl=http://mirrors.163.com/centos/7/os/x86_64/
enabled=1
gpgcheck=1
gpgkey=http://mirrors.163.com/centos/RPM-GPG-KEY-CentOS-7

#released updates
[updates]
name=CentOS-7 - Updates - 163.com
#mirrorlist=http://mirrorlist.centos.org/?release=7&arch=x86_64&repo=updates
baseurl=http://mirrors.163.com/centos/7/updates/x86_64/
gpgcheck=1
gpgkey=http://mirrors.163.com/centos/RPM-GPG-KEY-CentOS-7
enabled=1

#additional packages that may be useful
[extras]
name=CentOS-7 - Extras - 163.com
#mirrorlist=http://mirrorlist.centos.org/?release=7&arch=x86_64&repo=extras
baseurl=http://mirrors.163.com/centos/7/extras/x86_64/
gpgcheck=1
enabled=1
gpgkey=http://mirrors.163.com/centos/RPM-GPG-KEY-CentOS-7

#additional packages that extend functionality of existing packages
[centosplus]
name=CentOS-7 - Plus - 163.com
baseurl=http://mirrors.163.com/centos/7/centosplus/x86_64/
gpgcheck=1
enabled=0
gpgkey=http://mirrors.163.com/centos/RPM-GPG-KEY-CentOS-7

2）elrepo.repo

[elrepo]
name=ELRepo.org Community Enterprise Linux Repository - el7
baseurl=http://elrepo.org/linux/elrepo/el7/$basearch/
http://mirrors.coreix.net/elrepo/elrepo/el7/$basearch/
http://mirror.rackspace.com/elrepo/elrepo/el7/$basearch/
http://repos.lax-noc.com/elrepo/elrepo/el7/$basearch/
http://mirror.ventraip.net.au/elrepo/elrepo/el7/$basearch/
mirrorlist=http://mirrors.elrepo.org/mirrors-elrepo.el7
enabled=1
gpgcheck=1
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-elrepo.org
protect=0

[elrepo-testing]
name=ELRepo.org Community Enterprise Linux Testing Repository - el7
baseurl=http://elrepo.org/linux/testing/el7/$basearch/
http://mirrors.coreix.net/elrepo/testing/el7/$basearch/
http://mirror.rackspace.com/elrepo/testing/el7/$basearch/
http://repos.lax-noc.com/elrepo/testing/el7/$basearch/
http://mirror.ventraip.net.au/elrepo/testing/el7/$basearch/
mirrorlist=http://mirrors.elrepo.org/mirrors-elrepo-testing.el7
enabled=0
gpgcheck=1
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-elrepo.org
protect=0

[elrepo-kernel]
name=ELRepo.org Community Enterprise Linux Kernel Repository - el7
baseurl=http://elrepo.org/linux/kernel/el7/$basearch/
http://mirrors.coreix.net/elrepo/kernel/el7/$basearch/
http://mirror.rackspace.com/elrepo/kernel/el7/$basearch/
http://repos.lax-noc.com/elrepo/kernel/el7/$basearch/
http://mirror.ventraip.net.au/elrepo/kernel/el7/$basearch/
mirrorlist=http://mirrors.elrepo.org/mirrors-elrepo-kernel.el7
enabled=0
gpgcheck=1
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-elrepo.org
protect=0

[elrepo-extras]
name=ELRepo.org Community Enterprise Linux Extras Repository - el7
baseurl=http://elrepo.org/linux/extras/el7/$basearch/
http://mirrors.coreix.net/elrepo/extras/el7/$basearch/
http://mirror.rackspace.com/elrepo/extras/el7/$basearch/
http://repos.lax-noc.com/elrepo/extras/el7/$basearch/
http://mirror.ventraip.net.au/elrepo/extras/el7/$basearch/
mirrorlist=http://mirrors.elrepo.org/mirrors-elrepo-extras.el7
enabled=0
gpgcheck=1
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-elrepo.org
protect=0

3）epel.repo

            [epel]

name=Extra Packages for Enterprise Linux 7 - $basearch
baseurl=http://mirrors.aliyun.com/epel/7/$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 - $basearch - Debug
baseurl=http://mirrors.aliyun.com/epel/7/$basearch/debug
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.aliyun.com/epel/7/SRPMS
failovermethod=priority
enabled=0
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-EPEL-7
gpgcheck=0

然後執行以下操作：
                                        1：yum clean all
                                        2:：yum makecache
                                        3：yum update