Volumes and networks

Named volumes, bind mounts, and how Apple's networking differs.

Volumes

Create, inspect, remove and prune. Sizes come from the engine's disk-usage report where it has one.

Two things about volumes on Apple Containers are worth knowing before they bite you:

• A named volume is a real ext4 filesystem, so it arrives with a lost+found directory in it. Postgres refuses to initialise into a non-empty directory, so point PGDATA at a subdirectory:

  environment:
    PGDATA: /var/lib/postgresql/data/pgdata
  

• Anonymous volumes are not removed with their container. Docker cleans them up on --rm; Apple does not. Prune them from this view.

Bind mounts

Apple's runtime bind-mounts host directories directly, so there is no share list to maintain — which is a simplification over the VM Hopper used to run, where a path outside the shared set silently showed the container an empty directory.

Two caveats:

• only ro is honoured as a mount option
• a bind mount performs worse than a named volume, so put databases on volumes

Networks

Create, inspect, remove and prune. On macOS 26 Apple gives each container an address on its network, reachable from the host and from other containers on the same network, with DNS by container name. Separate networks are genuinely isolated from one another.

Attaching a running container to a network is an Engine API feature. Apple attaches containers to their networks when it creates them, so Hopper refuses rather than pretending.