docker - Dockerfile中是否需要 `FROM`子句？

Question

对于我遇到过的所有Dockerfile(虽然数量不多)，它们都使用FROM子句作为现有镜像的基础，即使它是FROM scratch。

这个条款是必需的吗？有没有FROM子句的Dockerfile是否可能？这样创建的容器可以执行任何操作吗？

编辑
我读

A Dockerfile with no FROM directive has no parent image, and is called a base image.

https://docs.docker.com/glossary/?term=parent%20image

但是我认为这可能是一个错误。

Answer 1

根据官方文档，它是必需的:

The FROM instruction initializes a new build stage and sets the Base Image for subsequent instructions. As such, a valid Dockerfile MUST start with a FROM instruction. The image can be any valid image – it is especially easy to start by pulling an image from the Public Repositories.

https://docs.docker.com/engine/reference/builder/#from