Understanding Docker Data Volumes and Data Volume Containers

This article is part of a Docker tutorial series; the first two parts covered basic concepts and image building.

When developing and testing frequently, rebuilding images for every change is inefficient, and containers lose their data when stopped, raising questions about data persistence and sharing across containers.

Volume (data volume) refers to a directory on the host that is mounted into a container, allowing the container to read and write files directly on the host’s disk.

Key points:

Data volumes store files on the host, so the data persists even if the container is removed.

Multiple containers can mount the same data volume, achieving data sharing.

Changes made by one container are immediately visible to all other containers using the same volume.

In summary, mounting a data volume lets containers indirectly operate on host‑disk files via a mapped directory.

Data Volume Container

If several containers need the same volume, you do not mount the host directory for each one. Instead, create a dedicated data‑volume container and mount the volume once with -v . Other containers can then attach to that volume using --volumes-from , without needing to know the host path.

The data‑volume container itself does not hold data; it merely provides the volume configuration. Even if the data‑volume container stops, other containers continue to access the data because the volume remains on the host, avoiding a single‑point‑of‑failure.

In practice, you simply add -v (to mount a host directory) or --volumes-from (to attach to a data‑volume container) to the docker run command to use data volumes.