NAME

       containers-transports  -  description  of  supported  transports  for  copying and storing
       container images

DESCRIPTION

       Tools which use the containers/image library, including skopeo(1), buildah(1),  podman(1),
       all  share  a  common  syntax for referring to container images in various locations.  The
       general form of the syntax is  transport:details,  where  details  are  dependent  on  the
       specified transport, which are documented below.

   containers-storage:[[storage-specifier]]{image-id|docker-reference[@image-id]}
       An  image  located  in  a  local  containers  storage.   The format of docker-reference is
       described in detail in the docker transport.

       The storage-specifier allows for referencing storage locations on the file system and  has
       the  format  [[driver@]root[+run-root][:options]]  where the optional driver refers to the
       storage driver (e.g., overlay or btrfs)  and  where  root  is  an  absolute  path  to  the
       storage's  root directory.  The optional run-root can be used to specify the run directory
       of the storage where all temporary writable content is stored.  The optional options are a
       comma-separated     list     of     driver-specific     options.     Please    refer    to
       containers-storage.conf(5) for further information on the drivers and supported options.

   dir:path
       An existing local directory path storing the manifest, layer tarballs  and  signatures  as
       individual  files.   This  is a non-standardized format, primarily useful for debugging or
       noninvasive container inspection.

   docker://docker-reference
       An image in a registry implementing the "Docker Registry HTTP API V2".  By  default,  uses
       the  authorization  state  in  $XDG_RUNTIME_DIR/containers/auth.json,  which  is set using
       podman-login(1).  If the authorization state is not found there, $HOME/.docker/config.json
       is checked, which is set using docker-login(1).  The containers-registries.conf(5) further
       allows for configuring various settings of a registry.

       Note that a docker-reference has the  following  format:  name[:tag|@digest].   While  the
       docker  transport  does  not support both a tag and a digest at the same time some formats
       like containers-storage do.  Digests can also be used in an image destination as  long  as
       the  manifest  matches  the  provided  digest.   The digest of images can be explored with
       skopeo-inspect(1).   If  name   does   not   contain   a   slash,   it   is   treated   as
       docker.io/library/name.   Otherwise, the component before the first slash is checked if it
       is recognized as a hostname[:port] (i.e., it contains either a . or a :, or the  component
       is  exactly  localhost).   If  the  first  component  of  name  is  not  recognized  as  a
       hostname[:port], name is treated as docker.io/name.

   docker-archive:path[:{docker-reference|@source-index}]
       An image is stored in  the  docker-save(1)  formatted  file.   docker-reference  must  not
       contain  a  digest.   Alternatively,  for  reading archives, @source-index is a zero-based
       index in archive manifest (to access untagged images).  If  neither  docker-reference  nor
       @_source_index  is specified when reading an archive, the archive must contain exactly one
       image.

       It is further possible to copy data to stdin by specifying  docker-archive:/dev/stdin  but
       note that the used file must be seekable.

   docker-daemon:docker-reference|algo:digest
       An image stored in the docker daemon's internal storage.  The image must be specified as a
       docker-reference or in an alternative algo:digest format  when  being  used  as  an  image
       source.  The algo:digest refers to the image ID reported by docker-inspect(1).

   oci:path[:tag]
       An  image compliant with the "Open Container Image Layout Specification" at path.  Using a
       tag is optional and allows for storing multiple images at the same path.

   oci-archive:path[:tag]
       An image compliant with the "Open Container Image Layout Specification" stored as a tar(1)
       archive at path.

   ostree:docker-reference[@/absolute/repo/path]
       An image in the local ostree(1) repository.  /absolute/repo/path defaults to /ostree/repo.

Examples

       The following examples demonstrate how some of the containers transports can be used.  The
       examples use skopeo-copy(1) for copying container images.

       Copying an image from one registry to another:

              $ skopeo copy docker://docker.io/library/alpine:latest docker://localhost:5000/alpine:latest

       Copying an image from a running Docker daemon to a directory in the OCI layout:

              $ mkdir alpine-oci
              $ skopeo copy docker-daemon:alpine:latest oci:alpine-oci
              $ tree alpine-oci
              test-oci/
              ├── blobs
              │   └── sha256
              │       ├── 83ef92b73cf4595aa7fe214ec6747228283d585f373d8f6bc08d66bebab531b7
              │       ├── 9a6259e911dcd0a53535a25a9760ad8f2eded3528e0ad5604c4488624795cecc
              │       └── ff8df268d29ccbe81cdf0a173076dcfbbea4bb2b6df1dd26766a73cb7b4ae6f7
              ├── index.json
              └── oci-layout

              2 directories, 5 files

       Copying an image from a registry to the local storage:

              $ skopeo copy docker://docker.io/library/alpine:latest containers-storage:alpine:latest

SEE ALSO

       docker-login(1),    docker-save(1),    ostree(1),     podman-login(1),     skopeo-copy(1),
       skopeo-inspect(1), tar(1), container-registries.conf(5), containers-storage.conf(5)

AUTHORS

       Miloslav     Trmač     mitr@redhat.com    ⟨mailto:mitr@redhat.com⟩    Valentin    Rothberg
       rothberg@redhat.com ⟨mailto:rothberg@redhat.com⟩