Docker Community Forums

Share and learn in the Docker community.

[RESOLVED] Files missing after Dockerfile RUN downloads them


(Ryan Sheehan) #1

I think I’m missing a fundamental aspect of the Dockerfile/build system. In the Dockerfile I have a run command that executes a shell script that downloads an application. The output from docker build shows everything works. When I go to run the container, none of the downloaded applications exist. After some simple testing it appears that subsequent RUN commands show that the downloaded data is no longer present. What am I not understanding?

My workaround at this point is to execute a container that runs the shell script to download the application followed by running the newly downloaded application.

Any advice is appreciated.


(Ryan Sheehan) #2

Found the source of all my headaches…

There was a volume declared in the base image I am using. For those unaware, the volume gets recreated at each subsequent step causing any changes to the directory in that volume to get blown out!

[REQUEST] can the build process output a warning if you make modifications to a directory that turns out to be a volume?