1、卸载老版本的Docker，没有安装则不卸载。
yum remove docker \
docker-client \
docker-client-latest \
docker-common \
docker-latest \
docker-latest-logrotate \
docker-logrotate \
docker-selinux \
docker-engine-selinux \
docker-engine
配置官方yum源，启用稳定版源配置。
[root@ChatDevOps-01 ~]# echo '[docker-ce-stable]
name=Docker CE Stable - $basearch
baseurl=https://download.docker.com/linux/CentOS/7/$basearch/stable
enabled=1
gpgcheck=1
gpgkey=https://download.docker.com/linux/centos/gpg
[docker-ce-stable-debuginfo]
name=Docker CE Stable - Debuginfo $basearch
baseurl=https://download.docker.com/linux/centos/7/debug-$basearch/stable
enabled=0
gpgcheck=1
gpgkey=https://download.docker.com/linux/centos/gpg
[docker-ce-stable-source]
name=Docker CE Stable - Sources
baseurl=https://download.docker.com/linux/centos/7/source/stable
enabled=0
gpgcheck=1
gpgkey=https://download.docker.com/linux/centos/gpg
[docker-ce-edge]
name=Docker CE Edge - $basearch
baseurl=https://download.docker.com/linux/centos/7/$basearch/edge
enabled=0
gpgcheck=1
gpgkey=https://download.docker.com/linux/centos/gpg
[docker-ce-edge-debuginfo]
name=Docker CE Edge - Debuginfo $basearch
baseurl=https://download.docker.com/linux/centos/7/debug-$basearch/edge
enabled=0
gpgcheck=1
gpgkey=https://download.docker.com/linux/centos/gpg
[docker-ce-edge-source]
name=Docker CE Edge - Sources
baseurl=https://download.docker.com/linux/centos/7/source/edge
enabled=0
gpgcheck=1
gpgkey=https://download.docker.com/linux/centos/gpg
[docker-ce-test]
name=Docker CE Test - $basearch
baseurl=https://download.docker.com/linux/centos/7/$basearch/test
enabled=0
gpgcheck=1
gpgkey=https://download.docker.com/linux/centos/gpg
[docker-ce-test-debuginfo]
name=Docker CE Test - Debuginfo $basearch
baseurl=https://download.docker.com/linux/centos/7/debug-$basearch/test
enabled=0
gpgcheck=1
gpgkey=https://download.docker.com/linux/centos/gpg
[docker-ce-test-source]
name=Docker CE Test - Sources
baseurl=https://download.docker.com/linux/centos/7/source/test
enabled=0
gpgcheck=1
gpgkey=https://download.docker.com/linux/centos/gpg
[docker-ce-nightly]
name=Docker CE Nightly - $basearch
baseurl=https://download.docker.com/linux/centos/7/$basearch/nightly
enabled=0
gpgcheck=1
gpgkey=https://download.docker.com/linux/centos/gpg
[docker-ce-nightly-debuginfo]
name=Docker CE Nightly - Debuginfo $basearch
baseurl=https://download.docker.com/linux/centos/7/debug-$basearch/nightly
enabled=0
gpgcheck=1
gpgkey=https://download.docker.com/linux/centos/gpg
[docker-ce-nightly-source]
name=Docker CE Nightly - Sources
baseurl=https://download.docker.com/linux/centos/7/source/nightly
enabled=0
gpgcheck=1
gpgkey=https://download.docker.com/linux/centos/gpg'>/etc/yum.repos.d/docker-ce.repo
此步骤中，需要注意的是：要启用哪个版本的源就将其下的enable值设置为1，其余设置为0。命令中的引号必须使用单引号。yum.repos.d目录下的文件必须以.repo结尾。
查看当前源的可用版本。
[root@ChatDevOps-01 ~]# yum list docker-ce --showduplicates|grep "^doc"|sort -r
docker-ce.x86_64 18.06.1.ce-3.el7 docker-ce-stable
docker-ce.x86_64 18.06.0.ce-3.el7 docker-ce-stable
docker-ce.x86_64 18.03.1.ce-1.el7.centos docker-ce-stable
docker-ce.x86_64 18.03.0.ce-1.el7.centos docker-ce-stable
docker-ce.x86_64 17.12.1.ce-1.el7.centos docker-ce-stable
docker-ce.x86_64 17.12.0.ce-1.el7.centos docker-ce-stable
docker-ce.x86_64 17.09.1.ce-1.el7.centos docker-ce-stable
docker-ce.x86_64 17.09.0.ce-1.el7.centos docker-ce-stable
docker-ce.x86_64 17.06.2.ce-1.el7.centos docker-ce-stable
docker-ce.x86_64 17.06.1.ce-1.el7.centos docker-ce-stable
docker-ce.x86_64 17.06.0.ce-1.el7.centos docker-ce-stable
docker-ce.x86_64 17.03.3.ce-1.el7 docker-ce-stable
docker-ce.x86_64 17.03.2.ce-1.el7.centos docker-ce-stable
docker-ce.x86_64 17.03.1.ce-1.el7.centos docker-ce-stable
docker-ce.x86_64 17.03.0.ce-1.el7.centos docker-ce-stable
安装docker-ce-18.06.0.ce-3.el7。若要安装其他版本则按照以下格式进行安装：docker-ce-