centos7.4 install docker-ce

天成1

　　1、uninstall old version docker



yum  -y remove  docker-common docker container-selinux docker-selinux docker-engine

　　Do not worry about the contents inside /var/lib/docker/, all will be preserved.
　　2、Let’s add the CE repository for docker installation.



wget https://download.docker.com/linux/centos/docker-ce.repo -O /etc/yum.repos.d/docker-ce.repo

　　3、Install the latest version of Docker CE using the following command.



yum -y install docker-ce

　　4、start the Docker service in case if it is not started automatically after the installation



systemctl start docker.service
systemctl enable docker.service

　　5、Create a group called docker if it does not exist, run the following commands with root privileges.



groupadd docker

　　6、Add a user that is to be a part of docker group, replace “asdf” with your own username.



useradd asdf

　　7、Add a user to docker group.



usermod -aG docker asdf

　　8、FirwallD in CentOS 7 can conflict with Docker; it is recommended to disable the service.



systemctl stop firewalld.service
systemctl disable firewalld.servic

　　When firewalld is started or restarted it will remove the DOCKER chain from iptables, it prevents Docker from working properly.
　　If you still want to use Systemd, firewalld is must be started before Docker service. In case if you start or restart firewalld after Docker, you will have to restart the Docker daemon.
　　That’s All!, You can now start working with Docker.