skopeo - Man Page

Command line utility used to interact with local and remote container images and container image registries

Jhon Honce August 2016

Synopsis

skopeo [global options] command [command options]

Description

skopeo is a command line utility providing various operations with container images and container image registries.

skopeo can copy container images between various containers image stores, converting them as necessary.  For example you can use skopeo to copy container images from one container registry to another.

skopeo can convert a Docker schema 2 or schema 1 container image to an OCI image.

skopeo can inspect a repository on a container registry without needlessly pulling the image. Pulling an image from a repository, especially a remote repository, is an expensive network and storage operation. Skopeo fetches the repository's manifest and displays a docker inspect-like json output about the repository or a tag. skopeo, in contrast to docker inspect, helps you gather useful information about a repository or a tag without requiring you to run docker pull - e.g. - Which tags are available for the given repository? Which labels does the image have?

skopeo can sign and verify container images.

skopeo can delete container images from a remote container registry.

Note: skopeo does not require any container runtimes to be running, to do most of its functionality.  It also does not require root, unless you are copying images into a container runtime storage backend, like the docker daemon or github.com/containers/storage.

Image Names

Most commands refer to container images, using a transport:details format. The following formats are supported:

containers-storage:docker-reference
 An image located in a local containers/storage image store.  Both the location and image store are specified in /etc/containers/storage.conf. (Backend for Podman, CRI-O, Buildah and friends)

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 either $XDG_RUNTIME_DIR/containers/auth.json, which is set using (skopeo login). If the authorization state is not found there, $HOME/.docker/config.json is checked, which is set using (docker login).

docker-archive:path[:docker-reference]
 An image is stored in the docker save formatted file.  docker-reference is only used when creating such a file, and it must not contain a digest.

docker-daemon:docker-reference
 An image docker-reference stored in the docker daemon internal storage.  docker-reference must contain either a tag or a digest.  Alternatively, when reading images, the format can be docker-daemon:algo:digest (an image ID).

oci:path:tag
 An image tag in a directory compliant with "Open Container Image Layout Specification" at path.

Options

--command-timeout duration
Timeout for the command execution.
--debug
enable debug output
--help|-h
Show help
--insecure-policy
Adopt an insecure, permissive policy that allows anything. This obviates the need for a policy file.
--override-arch arch
Use arch instead of the architecture of the machine for choosing images.
--override-os OS
Use OS instead of the running OS for choosing images.
--override-variant VARIANT
Use VARIANT instead of the running architecture variant for choosing images.
--policy path-to-policy
Path to a policy.json file to use for verifying signatures and deciding whether an image is trusted, overriding the default trust policy file.
--registries.d dir
use registry configuration files in dir (e.g. for container signature storage), overriding the default path.
--tmpdir dir
used to store temporary files. Defaults to /var/tmp.
--version|-v
print the version number

Commands

CommandDescription
skopeo-copy(1)Copy an image (manifest, filesystem layers, signatures) from one location to another.
skopeo-delete(1)Mark image-name for deletion.
skopeo-inspect(1)Return low-level information about image-name in a registry.
skopeo-list-tags(1)List the tags for the given transport/repository.
skopeo-login(1)Login to a container registry.
skopeo-logout(1)Logout of a container registry.
skopeo-manifest-digest(1)Compute a manifest digest of manifest-file and write it to standard output.
skopeo-standalone-sign(1)Sign an image.
skopeo-standalone-verify(1)Verify an image.
skopeo-sync(1)Copy images from one or more repositories to a user specified destination.

Files

/etc/containers/policy.json
 Default trust policy file, if --policy is not specified.
 The policy format is documented in containers-policy.json(5)https://github.com/containers/image/blob/master/docs/containers-policy.json.5.md⟩ .

/etc/containers/registries.d
 Default directory containing registry configuration, if --registries.d is not specified.
 The contents of this directory are documented in containers-policy.json(5)https://github.com/containers/image/blob/master/docs/containers-policy.json.5.md⟩.

See Also

skopeo-login(1), docker-login(1), containers-auth.json(5), containers-storage.conf(5), containers-policy.json(5), containers-transports(5)

Authors

Antonio Murdaca runcom@redhat.com ⟨mailto:runcom@redhat.com⟩, Miloslav Trmac mitr@redhat.com ⟨mailto:mitr@redhat.com⟩, Jhon Honce jhonce@redhat.com ⟨mailto:jhonce@redhat.com⟩

Referenced By

containers-transports(5), skopeo-copy(1), skopeo-delete(1), skopeo-inspect(1), skopeo-list-tags(1), skopeo-login(1), skopeo-logout(1), skopeo-manifest-digest(1), skopeo-standalone-sign(1), skopeo-standalone-verify(1), skopeo-sync(1), virt-bootstrap(1).

Man Pages