[root@localhost ~]# mv /etc/yum.repos.d/CentOS-Base.repo /etc/yum.repos.d/CentOS-Base.repo.backup

[root@localhost ~]# wget -O /etc/yum.repos.d/CentOS-Base.repo http://mirrors.aliyun.com/repo/Centos-7.repo

[root@localhost ~]# yum clean all
[root@localhost ~]# yum makecache

[root@localhost ~]# yum -y install docker-io

[root@localhost ~]# systemctl start docker

[root@localhost ~]# systemctl status docker.service

● docker.service - Docker Application Container EngineLoaded: loaded (/usr/lib/systemd/system/docker.service; disabled; vendor preset: disabled)Active: failed (Result: exit-code) since 三 2018-05-02 23:34:46 CST; 52s agoDocs: http://docs.docker.comProcess: 14416 ExecStart=/usr/bin/dockerd-current --add-runtime docker-runc=/usr/libexec/docker/docker-runc-current --default-runtime=docker-runc --exec-opt native.cgroupdriver=systemd --userland-proxy-path=/usr/libexec/docker/docker-proxy-current --seccomp-profile=/etc/docker/seccomp.json $OPTIONS $DOCKER_STORAGE_OPTIONS $DOCKER_NETWORK_OPTIONS $ADD_REGISTRY $BLOCK_REGISTRY $INSECURE_REGISTRY $REGISTRIES (code=exited, status=1/FAILURE)Main PID: 14416 (code=exited, status=1/FAILURE)5月 02 23:34:45 localhost.localdomain systemd[1]: Starting Docker Application Container Engine...
5月 02 23:34:45 localhost.localdomain dockerd-current[14416]: time="2018-05-02T23:34:45.527821208+08:00" level=warning msg="could not change group /var/run/...t found"
5月 02 23:34:45 localhost.localdomain dockerd-current[14416]: time="2018-05-02T23:34:45.532650572+08:00" level=info msg="libcontainerd: new containerd proce...: 14421"
5月 02 23:34:46 localhost.localdomain dockerd-current[14416]: time="2018-05-02T23:34:46.539484373+08:00" level=warning msg="overlay2: the backing xfs filesystem is ...
5月 02 23:34:46 localhost.localdomain dockerd-current[14416]: Error starting daemon: SELinux is not supported with the overlay2 graph driver on this kernel....d=false)
5月 02 23:34:46 localhost.localdomain systemd[1]: docker.service: main process exited, code=exited, status=1/FAILURE
5月 02 23:34:46 localhost.localdomain systemd[1]: Failed to start Docker Application Container Engine.
5月 02 23:34:46 localhost.localdomain systemd[1]: Unit docker.service entered failed state.
5月 02 23:34:46 localhost.localdomain systemd[1]: docker.service failed.
Hint: Some lines were ellipsized, use -l to show in full.

[root@localhost ~]# vi /etc/sysconfig/docker

# /etc/sysconfig/docker# Modify these options if you want to change the way the docker daemon runs
OPTIONS='--selinux-enabled=false --log-driver=journald --signature-verification=false'
if [ -z "${DOCKER_CERT_PATH}" ]; thenDOCKER_CERT_PATH=/etc/docker
fi
# ......省略N行

[root@localhost ~]# systemctl start docker

[root@localhost ~]# docker -v

[root@localhost ~]# vi /etc/docker/daemon.json

"registry-mirrors": ["https://njrds9qc.mirror.aliyuncs.com"]

[root@localhost ~]# systemctl daemon-reload

[root@localhost ~]# systemctl restart docker

[root@localhost tmp]# docker pull hello-world
Using default tag: latest
Trying to pull repository docker.io/library/hello-world ...
latest: Pulling from docker.io/library/hello-world
9bb5a5d4561a: Pull complete
Digest: sha256:f5233545e43561214ca4891fd1157e1c3c563316ed8e237750d59bde73361e77
Status: Downloaded newer image for docker.io/hello-world:latest

[root@localhost tmp]# docker run hello-worldHello from Docker!
This message shows that your installation appears to be working correctly.To generate this message, Docker took the following steps:1. The Docker client contacted the Docker daemon.2. The Docker daemon pulled the "hello-world" image from the Docker Hub.(amd64)3. The Docker daemon created a new container from that image which runs theexecutable that produces the output you are currently reading.4. The Docker daemon streamed that output to the Docker client, which sent itto your terminal.To try something more ambitious, you can run an Ubuntu container with:$ docker run -it ubuntu bashShare images, automate workflows, and more with a free Docker ID:https://hub.docker.com/

For more examples and ideas, visit:https://docs.docker.com/engine/userguide/