1)최신 containerd.io package를 수동으로 설치
dnf install https://download.docker.com/linux/centos/7/x86_64/stable/Packages/containerd.io-1.2.6-3.3.el7.x86_64.rpm
2)도커 설치
curl -sSL http://get.docker.com | bash
3)도커 실행하기
systemctl start docker
systemctl enable docker
4)도커 실행 여부 확인하기
docker version