--> Running transaction check
---> Package python-dateutil.noarch 0:1.5-7.el7 will be installed
---> Package python-ethtool.x86_64 0:0.8-8.el7 will be installed
---> Package python-inotify.noarch 0:0.9.4-4.el7 will be installed
---> Package python-syspurpose.x86_64 0:1.24.53-1.el7.centos will be installed
---> Package subscription-manager-rhsm.x86_64 0:1.24.53-1.el7.centos will be installed
--> Processing Conflict: 3:docker-ce-25.0.0-1.el7.x86_64 conflicts docker
--> Processing Conflict: 3:docker-ce-25.0.0-1.el7.x86_64 conflicts docker-io
--> Processing Conflict: 1:docker-ce-cli-25.0.0-1.el7.x86_64 conflicts docker
--> Processing Conflict: 1:docker-ce-cli-25.0.0-1.el7.x86_64 conflicts docker-io
--> Finished Dependency Resolution
Error: docker-ce conflicts with 2:docker-1.13.1-209.git7d71120.el7.centos.x86_64
Error: docker-ce-cli conflicts with 2:docker-1.13.1-209.git7d71120.el7.centos.x86_64
 You could try using --skip-broken to work around the problem
 You could try running: rpm -Va --nofiles --nodigest

安装都是正常，但是到这步就是出错，其实有解决方案的。最简单的解决方法如下：

curl -fsSL https://get.docker.com/ | sh

================上面的方法100%解决问题了=============

下面的方法是历史的，无需参考。

step 1: sudo yum erase docker

step 2: sudo yum clean all

step 3: sudo yum install docker-common-2

文章来源：https://stackoverflow.com/questions/41766075/centos-7-3-docker-engine-conflicts-with-docker-common-2