creating a volume with image driver

[iluminae]

I am putting this as a question at first in case I have a misunderstanding.

I am attempting to load the contents of a image as a volume, to be attached to containers at runtime.

following the docs I am able to create one from a image without error:

# podman volume create --driver image --opt image=docker.io/library/alpine:latest testVol
# ls $(podman volume mount testVol)

but the volume is always empty. I see the docs talk about creating a layer on top of the image so that writes to the volume become a layer on top of the image... but why is it empty? I expected the contents of the image to be available after creation.

rootful podman in podman machine on macos started with podman machine init --rootful --now -m 12000 --cpus 14 --volume="/Users:/Users"

# podman version
Client:       Podman Engine
Version:      4.6.2
API Version:  4.6.2
Go Version:   go1.20.7
Built:        Tue Sep 12 16:07:22 2023
OS/Arch:      linux/amd64

Thanks in advance.

Debug output

podman --debug volume create --driver=image --opt=image=docker.io/library/alpine:latest testVol

INFO[0000] podman filtering at log level debug
DEBU[0000] Called create.PersistentPreRunE(podman --debug volume create --driver=image --opt=image=docker.io/library/alpine:latest testVol)
DEBU[0000] Using conmon: "/usr/bin/conmon"
DEBU[0000] Initializing boltdb state at /var/lib/containers/storage/libpod/bolt_state.db
DEBU[0000] Using graph driver overlay
DEBU[0000] Using graph root /var/lib/containers/storage
DEBU[0000] Using run root /run/containers/storage
DEBU[0000] Using static dir /var/lib/containers/storage/libpod
DEBU[0000] Using tmp dir /run/libpod
DEBU[0000] Using volume path /var/lib/containers/storage/volumes
DEBU[0000] Using transient store: false
DEBU[0000] [graphdriver] trying provided driver "overlay"
DEBU[0000] Cached value indicated that overlay is supported
DEBU[0000] Cached value indicated that overlay is supported
DEBU[0000] Cached value indicated that metacopy is being used
DEBU[0000] NewControl(/var/lib/containers/storage/overlay): nextProjectID = 876785749
DEBU[0000] Cached value indicated that native-diff is not being used
INFO[0000] Not using native diff for overlay, this may cause degraded performance for building images: kernel has CONFIG_OVERLAY_FS_REDIRECT_DIR enabled
DEBU[0000] backingFs=xfs, projectQuotaSupported=true, useNativeDiff=false, usingMetacopy=true
DEBU[0000] Initializing event backend journald
DEBU[0000] Configured OCI runtime crun-wasm initialization failed: no valid executable found for OCI runtime crun-wasm: invalid argument
DEBU[0000] Configured OCI runtime runj initialization failed: no valid executable found for OCI runtime runj: invalid argument
DEBU[0000] Configured OCI runtime kata initialization failed: no valid executable found for OCI runtime kata: invalid argument
DEBU[0000] Configured OCI runtime krun initialization failed: no valid executable found for OCI runtime krun: invalid argument
DEBU[0000] Configured OCI runtime runsc initialization failed: no valid executable found for OCI runtime runsc: invalid argument
DEBU[0000] Configured OCI runtime youki initialization failed: no valid executable found for OCI runtime youki: invalid argument
DEBU[0000] Configured OCI runtime ocijail initialization failed: no valid executable found for OCI runtime ocijail: invalid argument
DEBU[0000] Using OCI runtime "/usr/bin/crun"
INFO[0000] Setting parallel job count to 43
DEBU[0000] Creating image-based volume
DEBU[0000] Looking up image "docker.io/library/alpine:latest" in local containers storage
DEBU[0000] Normalized platform linux/amd64 to {amd64 linux  [] }
DEBU[0000] Trying "docker.io/library/alpine:latest" ...
DEBU[0000] parsed reference into "[overlay@/var/lib/containers/storage+/run/containers/storage:overlay.mountopt=nodev,metacopy=on]@8ca4688f4f356596b5ae539337c9941abc78eda10021d35cbc52659c74d9b443"
DEBU[0000] Found image "docker.io/library/alpine:latest" as "docker.io/library/alpine:latest" in local containers storage
DEBU[0000] Found image "docker.io/library/alpine:latest" as "docker.io/library/alpine:latest" in local containers storage ([overlay@/var/lib/containers/storage+/run/containers/storage:overlay.mountopt=nodev,metacopy=on]@8ca4688f4f356596b5ae539337c9941abc78eda10021d35cbc52659c74d9b443)
DEBU[0000] exporting opaque data as blob "sha256:8ca4688f4f356596b5ae539337c9941abc78eda10021d35cbc52659c74d9b443"
DEBU[0000] parsed reference into "[overlay@/var/lib/containers/storage+/run/containers/storage:overlay.mountopt=nodev,metacopy=on]@8ca4688f4f356596b5ae539337c9941abc78eda10021d35cbc52659c74d9b443"
DEBU[0000] exporting opaque data as blob "sha256:8ca4688f4f356596b5ae539337c9941abc78eda10021d35cbc52659c74d9b443"
DEBU[0000] Cached value indicated that idmapped mounts for overlay are supported
DEBU[0000] SetQuota path=/var/lib/containers/storage/overlay/44719c1c9911d40dd3547b23d9533ae008c59227646ce6fca57b3bfe49643f85, size=0, inodes=0, projectID=876785749
DEBU[0000] Created container "30b320acec429052ed2101b4b1924aeef7a0e04bad3ed878d24e6781b19d20e6"
DEBU[0000] Container "30b320acec429052ed2101b4b1924aeef7a0e04bad3ed878d24e6781b19d20e6" has work directory "/var/lib/containers/storage/overlay-containers/30b320acec429052ed2101b4b1924aeef7a0e04bad3ed878d24e6781b19d20e6/userdata"
DEBU[0000] Container "30b320acec429052ed2101b4b1924aeef7a0e04bad3ed878d24e6781b19d20e6" has run directory "/run/containers/storage/overlay-containers/30b320acec429052ed2101b4b1924aeef7a0e04bad3ed878d24e6781b19d20e6/userdata"
DEBU[0000] NewControl(/var/lib/containers/storage/volumes): nextProjectID = 247577571
DEBU[0000] SetQuota path=/var/lib/containers/storage/volumes/testVol/_data, size=0, inodes=0, projectID=247577571
testVol
DEBU[0000] Called create.PersistentPostRunE(podman --debug volume create --driver=image --opt=image=docker.io/library/alpine:latest testVol)
DEBU[0000] Shutting down engines

podman volume inspect testVol

[
     {
          "Name": "testVol",
          "Driver": "image",
          "Mountpoint": "/var/lib/containers/storage/volumes/testVol/_data",
          "CreatedAt": "2023-09-29T12:46:56.239640505-04:00",
          "Labels": {},
          "Scope": "local",
          "Options": {
               "image": "docker.io/library/alpine:latest"
          },
          "MountCount": 0,
          "NeedsCopyUp": true,
          "NeedsChown": true,
          "StorageID": "30b320acec429052ed2101b4b1924aeef7a0e04bad3ed878d24e6781b19d20e6",
          "LockNumber": 5
     }
]