How to copy files from docker build to host machine?

This guide is all about copy/extract file from docker build process, then copy it to host machine.

This method is very useful when you have to release/package .rpm file for further usage, but in this post, I will use mkdocs for example, I build mkdocs html files with docker, then copy those html files to host machine.

There are two things to consider:

• Dockerfile
• And Build Command for that Dockerfile

I. Dockerfile

The key note is line number 8 and 9

1
2
3
4
5
6
7
8
9
FROM python:3.13.0 AS build

WORKDIR /opt/mining_rig_monitor_document_src
COPY . /opt/mining_rig_monitor_document_src
RUN pip install -r requirements.txt
RUN mkdocs build -c

FROM scratch AS release
COPY --from=build /opt/mining_rig_monitor_document_src/site /

RUN mkdocs build -c will create a directory named site which stores all html files. Then, from scratch image, we copy all thoses html files to /

II. Docker build command

This following command will copy all files from release stage to nginx-dist. The most important is environment variable DOCKER_BUILDKIT=1

$ DOCKER_BUILDKIT=1 docker build -f  Dockerfile --target=release --output nginx-dist .

➜ mining_rig_monitor_document (master) ✗ pwd
/home/nguyenvinhlinh/Projects/mining_rig_monitor_document


➜ mining_rig_monitor_document (master) ✗ tree -L 1
.
├── Dockerfile
├── docs
├── mkdocs.yml
├── nginx-dist      <<-- your files from docker build
├── readme.md
├── requirements.txt
└── wireframe