docker volume example

this is a test repo to show an issue I ran into with volume sharing in the docker-orchestrating-docker pattern.

Running the example

$ ./start.sh

Will tell docker to build and run Prep.dockerfile. This container creates a volume to store some the files within the repo:

• vol_scripts which contains all the *.sh files

The issue

The prep container will build successfully, but the docker run command will fail with an error similar to cp: can't stat '/app/*.sh': No such file or directory

This happens whenever a container attempts to access a volume that is in use inside another container. In this case it's the /app volume on the prep container that is causing the error, since prep.sh attempts to bind-mount that directory into a container in order to populate the other docker volumes with data.

The workaround

So far the workaround has been to take any data that you need to share between containers that are run via the DOD pattern and store it in volumes before you launch the container and mount them in using the -v or --mount options of docker run.