mirror of
https://github.com/Brandon-Rozek/website.git
synced 2024-12-24 17:04:28 +00:00
48 lines
1.4 KiB
Markdown
48 lines
1.4 KiB
Markdown
---
|
|
title: "Advanced Docker Image Construction with Bash"
|
|
date: 2019-12-26T21:01:37-05:00
|
|
draft: false
|
|
tags: [ "linux", "containers", "bash" ]
|
|
---
|
|
|
|
On current versions of Docker, you can't mount volumes during image construction. This poses an issue for me as I don't want to replicate gigabytes of data already existing on my disk when it won't appear on the final build. Therefore, instead of building an image with a traditional Dockerfile, we're going to use a bash script on a running base image container and export the filesystem to create the image from.
|
|
|
|
So first run the base image with the mounts that you want
|
|
|
|
```bash
|
|
docker run -v /mnt:/mnt -td --name containername baseimage /bin/bash
|
|
```
|
|
|
|
Then copy whatever `setup` script you have and execute it on the running container
|
|
|
|
```bash
|
|
docker cp setup containername:/setup
|
|
docker exec -it containername /setup
|
|
```
|
|
|
|
Once the setup script finalizes, we can export the container filesystem into a file called `image.tar`
|
|
|
|
```bash
|
|
docker export --output="image.tar" containername
|
|
```
|
|
|
|
Once we've exported the filesystem, we can get rid of the existing container
|
|
|
|
```bash
|
|
docker stop containername && docker rm containername
|
|
```
|
|
|
|
Now create a `Dockerfile` with the following:
|
|
|
|
```dockerfile
|
|
FROM scratch
|
|
ADD image.tar /
|
|
CMD ["bin/bash"]
|
|
```
|
|
|
|
Now you can create the image by building the Dockerfile
|
|
|
|
```bash
|
|
docker build -t finalimagename .
|
|
```
|
|
|