No packages marked for update

问题：用yum安装docker，更新yum存储时，报以下错误，导致yum坏了

[root@localhost yum.repos.d]# vi docker.repo
[root@localhost yum.repos.d]# yum update
Loaded plugins: fastestmirror, langpacks
base                                                     | 3.6 kB     :
dockerrepo                                               | 2.9 kB     :
extras                                                   | 3.4 kB     :
updates                                                  | 3.4 kB     :
dockerrepo//primary_db                                    |   kB   :
Loading mirror speeds from cached hostfile
 * base: mirrors.cn99.com
 * extras: mirrors.aliyun.com
 * updates: mirrors.cn99.com
No packages marked for update

解决方法：重新安装yum

[root@localhost ~]# rpm -qa|grep yum|xargs rpm -e --nodeps
[root@localhost ~]# rpm -qa |grep yum
[root@localhost ~]# wget http://centos.ustc.edu.cn/centos/7/os/x86_64/Packages/yum-metadata-parser-1.1.4-10.el7.x86_64.rpm
[root@localhost ~]# wget http://centos.ustc.edu.cn/centos/7/os/x86_64/Packages/yum-3.4.3-154.el7.centos.noarch.rpm
[root@localhost ~]# wget http://centos.ustc.edu.cn/centos/7/os/x86_64/Packages/yum-plugin-fastestmirror-1.1.31-42.el7.noarch.rpm
[root@localhost ~]# rpm -ivh yum-*
Preparing...                          ################################# [%]
Updating / installing...
   :yum-metadata-parser-1.1.-.el7 ################################# [ %]
   :yum-plugin-fastestmirror-1.1.-################################# [ %]
   :yum-3.4.-.el7.centos         ################################# [%]
[root@localhost ~]# wget http://docs.linuxtone.org/soft/lemp/CentOS-Base.repo
[root@localhost ~]# yum makecache
Loaded plugins: fastestmirror
base                                                     | 3.6 kB     :
extras                                                   | 3.4 kB     :
updates                                                  | 3.4 kB     :
(/): extras//x86_64/other_db                            |  kB   :
(/): extras//x86_64/filelists_db                        |  kB   :
(/): updates//x86_64/prestodelta                        |  kB   :
(/): extras//x86_64/prestodelta                         |  kB   :
(/): updates//x86_64/other_db                           |  kB   :
(/): updates//x86_64/filelists_db                       | 3.5 MB   :
(/): base//x86_64/filelists_db                          | 6.7 MB   :
(/): base//x86_64/other_db                              | 2.5 MB   :
Loading mirror speeds from cached hostfile
 * base: mirrors..com
 * extras: mirrors.aliyun.com
 * updates: mirrors.cn99.com
Metadata Cache Created