Virtualization & Docker

Docker up & running:

引用

A
container, on the other hand, is just another process that talks directly to the Linux
kernel and therefore can utilize more resources, up until the system or quota-based
limits are reached.

official sites:
Inside Docker
To understand Docker’s internals, you need to know about three components:

Docker images.
Docker registries.
Docker containers.

Docker images
A Docker image is a read-only template. For example, an image could contain an Ubuntu operating system with Apache and your web application installed. Images are used to create Docker containers. Docker provides a simple way to build new images or update existing images, or you can download Docker images that other people have already created. Docker images are the build component of Docker.

Docker registries
Docker registries hold images. These are public or private stores from which you upload or download images. The public Docker registry is provided with the Docker Hub. It serves a huge collection of existing images for your use. These can be images you create yourself or you can use images that others have previously created. Docker registries are the distribution component of Docker.

Docker containers
Docker containers are similar to a directory. A Docker container holds everything that is needed for an application to run. Each container is created from a Docker image. Docker containers can be run, started, stopped, moved, and deleted. Each container is an isolated and secure application platform. Docker containers are the run component of Docker.

namespace: for 环境隔离
cgroups：for 资源隔离