默认情况下，Docker是由CentOS-extras仓库提供的。下面是一些你可能需要熟悉的命令：

# To search everything 'docker' related

yum search docker

# Once found interesting package...

yum info docker

在普通示例（即没有导入任何无关/第三方存储库）上，输出应类似于以下内容

Available Packages
Name        : docker
Arch        : x86_64
Epoch       : 2
Version     : 1.13.1
Release     : 96.gitb2f74b2.el7.centos
Size        : 18 M
Repo        : extras/7/x86_64
Summary     : Automates deployment of containerized applications
URL         : https://github.com/docker/docker
License     : ASL 2.0
Description : Docker is an open-source engine that automates the deployment of any
            : application as a lightweight, portable, self-sufficient container that will
            : run virtually anywhere.
            : 
            : Docker containers can encapsulate any payload, and will run consistently on
            : and between virtually any server. The same container that a developer builds
            : and tests on a laptop will run at scale, in production*, on VMs, bare-metal
            : servers, OpenStack clusters, public instances, or combinations of the above.

然后，为了获取（大多数情况下）特定rpm的源软件包，请尝试以下命令（假设您以前安装了yum-utils

# Disable all repos, enable the one we have eyes on, set 'source only' and download

yumdownloader --disablerepo=\* --enablerepo=extras --source docker

下面是命令的输出

Initializing download: http://vault.centos.org/centos/7/extras/Source/SPackages/docker-1.13.1-96.gitb2f74b2.el7.centos.src.rpm
File size: 14604391 bytes
Opening output file ./docker-1.13.1-96.gitb2f74b2.el7.centos.src.rpm
Starting download

Connection 2 finished                                                          ] 41% [============================-                                         ]  0.0 B/s | 5.8 MB  --:--:-- ETA 
Connection 4 finished                                                          ]
Connection 0 finished                                                          ]
Connection 1 finished                                                          ]
[100%] [..................................................] [  14.6MB/s] [00:00]100% [======================================================================] 8.1 MB/s |  14 MB  00:00:00 ETA 

Downloaded 13.9 megabytes in 0 seconds. (14921.07 KB/s)
docker-1.13.1-96.gitb2f74b2.el7.centos.src.rpm                                                                                                                         |  14 MB  00:00:01

一旦文件下载完毕，您可以解压缩或安装rpm来访问内容。Midnight Commander还可以列出/查看/复制/解压缩大多数rpm存档到您选择的目录中。

rpm -Uvh docker-1.13.1-96.gitb2f74b2.el7.centos.src.rpm
Updating / installing...
   1:docker-2:1.13.1-96.gitb2f74b2.el7################################# [100%]

文件应该已经安装在$HOME/rpmbuild SPECS文件夹将包含规格文件和SOURCES将包含源代码，已编译，以创建上述软件包。
在本例中，源代码文件位于$HOME/rpmbuild/SOURCES/b2f74b220126bddbae585cfe2406498ced3ae065.tar.gz中
用于创建rpm包的specfile也是一个有趣的东西。在这个文件中，你会发现编译前/后的特殊内容/修改，这些内容是包维护者或发布者所“专有”的。