Volumes versus Filesystem and Images

Note that volumes are not part of images, so the data saved on volumes won't be uploaded or downloaded with images. The volumes will be engraved in the image, but not its data. Therefore, if you want to save certain data in an image, save it as a file, not as a volume.

The next exercise will demonstrate and clarify the different outputs between saving data on volumes and when saving it on files.

Exercise 7.10: Saving a File on a Volume and Committing It to a New Image

In this exercise, you will run a container with a volume, save some data on the volume, commit the container to a new image, and craft a new container based on this new image. When you check the data from inside the container, you will not find it. The data will be lost. This exercise will demonstrate how the data will be lost when committing the container to a new image. Remember that the data on the volumes will not be engraved in the new image:

1. Create a new...