ubuntu14安装docker-ce

先卸载旧的docker

sudo apt-get remove docker docker-engine docker.io docker-ce

通过HTTPS使用存储库（repository）

sudo apt-get install -y apt-transport-https ca-certificates curl software-properties-common

添加Docker官方的GPG密钥

curl -fsSL https://download.docker.com/linux/ubuntu/gpg | sudo apt-key add -

设置stable存储库

sudo add-apt-repository "deb [arch=amd64] https://download.docker.com/linux/ubuntu $(lsb_release -cs) stable"

更新一下apt包索引

sudo apt-get update

安装最新版本的Docker CE

sudo apt-get install -y docker-ce

或者列出版本，选择安装

apt-cache madison docker-ce

sudo apt-get install docker-ce=<VERSION>

例子：

sudo apt-get install docker-ce=17.12.1~ce-0~ubuntu

查看服务状态

jiqing@ThinkPad:~$ sudo /etc/init.d/docker start
start: Job is already running: docker
jiqing@ThinkPad:~$ sudo /etc/init.d/docker stop
docker stop/waiting
jiqing@ThinkPad:~$ sudo /etc/init.d/docker status
docker stop/waiting
jiqing@ThinkPad:~$ sudo /etc/init.d/docker restart
stop: Unknown instance:
docker start/running, process 31877

验证是否正常，sudo docker run hello-world

jiqing@ThinkPad:~$ sudo docker run hello-world
Unable to find image 'hello-world:latest' locally
latest: Pulling from library/hello-world
9bb5a5d4561a: Pull complete
Digest: sha256:f5233545e43561214ca4891fd1157e1c3c563316ed8e237750d59bde73361e77
Status: Downloaded newer image for hello-world:latest

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/engine/userguide/

一切都是ok的。

ps：io，engine都是docker的早期版本。ce是社区版本，比较新。ee是企业版本。