docker-ce安装

https://docs.docker.com/install/linux/docker-ce/centos/

卸载旧版本

$ sudo yum remove docker \
                  docker-client \
                  docker-client-latest \
                  docker-common \
                  docker-latest \
                  docker-latest-logrotate \
                  docker-logrotate \
                  docker-engine

安装Docker Engine - Community

安装依赖包

$ sudo yum install -y yum-utils \
  device-mapper-persistent-data \
  lvm2

安装docker-ce stable yum源

$ sudo yum-config-manager \
    --add-repo \
    https://download.docker.com/linux/centos/docker-ce.repo

启用docker-ce-nightly ,docker-ce-test

$ sudo yum-config-manager --enable docker-ce-nightly
$ sudo yum-config-manager --enable docker-ce-test

安装docker-ce

$ sudo yum install docker-ce docker-ce-cli containerd.io

报错信息：

问题: package docker-ce-3:19.03.2-3.el7.x86_64 requires \
　containerd.io >= 1.2.2-3, but none of the providers can be installed
- cannot install the best candidate for the job
- package containerd.io-1.2.2-3.3.el7.x86_64 is excluded
- package containerd.io-1.2.2-3.el7.x86_64 is excluded
- package containerd.io-1.2.4-3.1.el7.x86_64 is excluded
- package containerd.io-1.2.5-3.1.el7.x86_64 is excluded
- package containerd.io-1.2.6-3.3.el7.x86_64 is excluded
(try to add '--skip-broken' to skip uninstallable packages \
 or '--nobest' to use not only best candidate packages)

检查发现containerd.io此软件包已经安装，但版本是1.2.0；所以造成这种安装失败的原因是containerd.io软件包版本过低
解决方法：
1.安装低版本的docker-ce
2.更新containerd.io
此处选择第二种方法。
下载安装包containerd.io-1.2.6

$ wget https://download.docker.com/linux/centos/7/x86_64/  \
       edge/Packages/containerd.io-1.2.6-3.3.el7.x86_64.rpm　　

更新containerd.io

 $ yum -y install containerd.io-1.2.6-3.3.el7.x86_64.rpm

解决办法参考来源：https://www.cnblogs.com/kuiyajia/articles/11585493.html

安装完成后重新安装Docker。

$ sudo yum install docker-ce docker-ce-cli 

启动docker

$ sudo systemctl start docker

用hello-world检测docker-ce安装完成

$ sudo docker run hello-world

出现如下消息表明安装成功。

Hello 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 the
    executable that produces the output you are currently reading.
 4. The Docker daemon streamed that output to the Docker client, which sent it
    to your terminal.

To try something more ambitious, you can run an Ubuntu container with:
 $ docker run -it ubuntu bash

Share images, automate workflows, and more with a free Docker ID:
 https://hub.docker.com/

For more examples and ideas, visit:
 https://docs.docker.com/get-started/