# Bind-mount overlay — replaces the `data` named volume with a bind mount
# to /data on the host.
#
# Use this when /data is a persistent disk mounted by the VM startup script,
# so Agnes data lives on the PD (not on the boot disk's Docker volume).
#
# `bind,rbind` (recursive bind) is required when the host nests a second
# disk under /data — e.g. the dual-disk layout where sdb is mounted on /data
# and sdc on /data/state. A plain `bind` captures only the top-level mount
# and silently shadows the sub-mount with an empty subdirectory inside the
# container, causing the app to write to the wrong disk.
#
# Usage (combined with docker-compose.prod.yml):
#   docker compose \
#     -f docker-compose.yml \
#     -f docker-compose.prod.yml \
#     -f docker-compose.host-mount.yml \
#     up -d
#
# Do NOT use this overlay in CI — /data does not exist on GitHub runners.
volumes:
  data:
    driver: local
    driver_opts:
      type: none
      o: bind,rbind
      device: /data