为什么“ https://get.docker.com/ubuntu”是一个apt存储库？

位于https://get.docker.com/ubuntu/的页面包含一个可用于安装docker的脚本

# check that httpS transport is available to APT
if [ ! -e /usr/lib/apt/methods/https ]; then
    apt-get update
    apt-get install -y apt-transport-https
fi

# Add the repository to your APT sources
echo deb https://get.docker.com/ubuntu docker main > /etc/apt/sources.list.d/docker.list

# Then import the repository key
apt-key adv --keyserver hkp://keyserver.ubuntu.com:80 --recv-keys 36A1D7869245C8950F966E92D8576A8BA88D21E9

# Install docker
apt-get update
apt-get install -y lxc-docker

但是apt-get不使用此脚本,必须手动运行.

该脚本使用以下内容创建配置文件/etc/apt/sources.list.d/docker.list：

deb https://get.docker.com/ubuntu docker main

运行apt-get update时,将使用此配置文件,而Apt-get update将使用该行并从中建立以下URL

https://get.docker.com/ubuntu/dists/docker/main/binary-amd64/Packages

软件包管理系统的软件包高速缓存将使用“软件包”文件中描述的软件包进行更新.

Package: lxc-docker
Version: 1.5.0
License: Apache-2.0
vendor: none
Architecture: amd64
Maintainer: support@docker.com
Installed-Size: 0
Depends: lxc-docker-1.5.0
Homepage: http://www.docker.com/
Priority: extra
Section: default
Filename: pool/main/l/lxc-docker/lxc-docker_1.5.0_amd64.deb
Size: 2092
SHA256: 2e8b061216cc45343197e52082175bc671af298d530652436dc16d0397f986f0
SHA1: 24a0314bd7f6fdf79b69720de60be77510d689af
MD5sum: 923cad1a2af2d6b0a3e8fa909ba26ca4
Description: Linux container runtime Docker complements LXC with a high-level API which operates at the process level. It runs unix processes with strong guarantees of isolation and repeatability across servers. Docker is a great building block for automaTing diStributed systems: large-scale web deployments,database clusters,conTinuous deployment systems,private PaaS,service-oriented architectures,etc.
....

最后,apt-get upgrade将下载并安装软件包.