Docker 볼륨으로 데이터 영속화하기

When a container is removed, everything written inside its writable layer is gone. For databases, uploads, or logs you need storage that survives the container.

Docker offers two main mechanisms:

• Volumes: managed by Docker, stored in a dedicated area
• Bind mounts: map a specific host folder into the container

Volumes are the recommended default.

Create a named volume with docker volume create. Docker manages where it physically lives.

Attach the volume to a container path with -v. Anything written to that path persists in the volume.

A bind mount maps a host directory into the container, great for live-editing source code during development.

See all volumes with docker volume ls, and view details, including the mount point, with docker volume inspect.

In docker-compose.yml you declare volumes once and reference them in services. Use single quotes and indentation, never tabs.

Multiple containers can mount the same volume to share files, for example an app writing files and a backup container reading them.

Append :ro to mount a volume read-only when a container should never modify the data, adding a safety guard.

Back up a volume by running a throwaway container that tars its contents to the host.

Orphaned volumes waste disk. Remove a named one with docker volume rm, or clear all unused volumes with docker volume prune, carefully.

Test your understanding of Docker storage.

You learned to persist data in Docker:

• Containers are ephemeral; use volumes or bind mounts for durable data
• Mount with -v name:/path; use bind mounts for live dev
• Declare volumes in Compose and share them between containers
• Back up, mount read-only, and prune unused volumes

Volumes let your databases and files outlive any single container.