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⟩

Transports                                         Containers                           CONTAINERS-TRANSPORTS(5)