使用yum可以进行连通依赖关系一起进行安装，而是用–downloadonly –downloaddir选项则可以不进行安装，而将rpm连同依赖下载到本地进行安装。
下载及安装方式
使用yum安装centos或者rhel等自带的docker，可以使用yum install docker. 而下载到本地后使用安装文件的方式可以使用如下方式
下载docker相关的rpm文件并安装
使用下载rmp并安装的方式进行docker的安装
downloaddir指定的文件夹如果事前不存在，在执行的时候会生成一个。
安装日志
downloaddir指定的文件夹如果事前不存在，在执行的时候会生成一个。
[root@openshift ~]# yum install --downloadonly --downloaddir=/tmp/docker docker
Failed to set locale, defaulting to C
Loaded plugins: fastestmirror
Loading mirror speeds from cached hostfile
* base: mirrors.163.com
* extras: mirrors.cn99.com
* updates: mirror.lzu.edu.cn
Resolving Dependencies
--> Running transaction check
---> Package docker.x86_64 2:1.13.1-53.git774336d.el7.centos will be installed
--> Processing Dependency: docker-common = 2:1.13.1-53.git774336d.el7.centos for package: 2:docker-1.13.1-53.git774336d.el7.centos.x86_64
--> Processing Dependency: docker-client = 2:1.13.1-53.git774336d.el7.centos for package: 2:docker-1.13.1-53.git774336d.el7.centos.x86_64
--> Running transaction check
---> Package docker-client.x86_64 2:1.13.1-53.git774336d.el7.centos will be installed
---> Package docker-common.x86_64 2:1.13.1-53.git774336d.el7.centos will be installed
--> Processing Dependency: skopeo-containers >= 1:0.1.26-2 for package: 2:docker-common-1.13.1-53.git774336d.el7.centos.x86_64
--> Processing Dependency: oci-umount >= 2:2.0.0-1 for package: 2:docker-common-1.13.1-53.git774336d.el7.centos.x86_64
--> Processing Dependency: oci-systemd-hook >= 1:0.1.4-9 for package: 2:docker-common-1.13.1-53.git774336d.el7.centos.x86_64
--> Processing Dependency: oci-register-machine >= 1:0-5.13 for package: 2:docker-common-1.13.1-53.git774336d.el7.centos.x86_64
--> Processing Dependency: container-storage-setup >= 0.7.0-1 for package: 2:docker-common-1.13.1-53.git774336d.el7.centos.x86_64
--> Processing Dependency: container-selinux >= 2:2.21-2 for package: 2:docker-common-1.13.1-53.git774336d.el7.centos.x86_64
--> Running transaction check
---> Package container-selinux.noarch 2:2.42-1.gitad8f0f7.el7 will be installed
--> Processing Dependency: policycoreutils-python for package: 2:container-selinux-2.42-1.gitad8f0f7.el7.noarch
