（转）Ubuntu 16.04 安裝Docker（PS：本文适用amd64位的ubuntu系统）

1.前置安裝，確保你的系統是64位

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

2.添加Docker官方GPG key

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

验证key

$ sudo apt-key fingerprint 0EBFCD88

确保key fingerprint是 ：9DC8 5822 9FC7 DD38 854A E2D8 8D81 803C 0EBF CD88

3.安装仓库

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

4.安装Docker

$ sudo apt-get update
$ sudo apt-get install docker-ce

如果安装不上的话，就加上 --fix missing
如果没有docker的话，就注册一个，执行 docker login 然后自己写一个用户名，密码，邮箱，去邮箱验证一下就行了.

5.测试Doker

$ sudo docker run hello-world

看到如下输出则表示安装成功：

Unable to find image 'hello-world:latest' locally
latest: Pulling from library/hello-world
78445dd45222: Pull complete 
Digest: sha256:c5515758d4c5e1e838e9cd307f6c6a0d620b5e07e6f927b07d05f6d12a1ac8d7
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.
 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://cloud.docker.com/

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

解决apt-get install E: 无法定位软件包问题

在etc/apt   的sources.list 添加镜像源   deb http://archive.ubuntu.com/ubuntu/ trusty main universe restricted multiverse
然后 sudo apt-get update  接着安装就可以了

另外的安装方法

简单方法

$ sudo apt-get update
$ sudo apt-get install docker
搞定！ 
但是这种方法有一个缺点：安装的不一定是最新的docker，安装版本是1.10.2，不过，对于docker使用没任何什么问题，如果要后续升级方便，可以使用下面的方法。

另一种方法

1.切换到root权限或者用sudo

2.升级source列表并保证https和ca证书成功安装

# apt-get update
# apt-get install apt-transport-https ca-certificates
3.增加新的GPG 密钥

# apt-key adv --keyserver hkp://p80.pool.sks-keyservers.net:80 --recv-keys 58118E89F3A912897C070ADBF76221572C52609D
4.新增或编辑source列表里的docker.list文件

# vi /etc/apt/sources.list.d/docker.list  //如果不存在就新增
5.删除已有的entries

6.按照系统版本增加entry(Ubuntu Xenial 16.04 (LTS)）

deb https://apt.dockerproject.org/repo ubuntu-xenial main
7.重新执行更新操作，并删除老的repo

# apt-get purge lxc-docker  //没有安装的话，跳过
8.查看是否有正确的可用版本

# apt-cache policy docker-engine

如图：

9.从14.04版本以上开始docker推荐安装linux-image-extra

# apt-get install linux-image-extra-$(uname -r)
10.安装docker

# apt-get update
# apt-get install docker-engine
# service docker start
# docker run hello-world
到此结束，the end！