After docker is installed, start docker and report an error, docker: unrecognized service.
1. Run yum remove docker to delete the installation
2. Reinstall yum install https://get.docker.com/rpm/1.7.1/centos-6/RPMS/x86_64/docker-engine-1.7.1-1.el6.x86_64.rpm
3. Just start the service service docker start
Then directly pull the corresponding image and run it.