CentOSにdockerを入れる。公式の手順に沿うだけ。
$ sudo yum remove docker \
docker-client \
docker-client-latest \
docker-common \
docker-latest \
docker-latest-logrotate \
docker-logrotate \
docker-selinux \
docker-engine-selinux \
docker-engine
$ sudo yum install -y yum-utils device-mapper-persistent-data lvm2
$ sudo yum-config-manager --add-repo https://download.docker.com/linux/centos/docker-ce.repo
$ sudo yum-config-manager --enable docker-ce-test
$ sudo yum install docker-ce
$ sudo systemctl start docker
$ sudo docker run hello-world
$ sudo systemctl enable docker