skopeo-sync - Man Page
Synchronize images between registry repositories and local directories.
Synopsis
skopeo sync [options] --src transport --dest transport source destination
Description
Synchronize images between registry repositories and local directories. Synchronization is achieved by copying all the images found at source to destination - useful when synchronizing a local container registry mirror or for populating registries running inside of air-gapped environments.
Differently from other skopeo commands, skopeo sync requires both source and destination transports to be specified separately from source and destination. One of the problems of prefixing a destination with its transport is that, the registry docker://hostname:port would be wrongly interpreted as an image reference at a non-fully qualified registry, with hostname and port the image name and tag.
Available source transports:
- docker (i.e. --src docker): source is a repository hosted on a container registry (e.g.: registry.example.com/busybox).
If no image tag is specified, skopeo sync copies all the tags found in that repository.
- dir (i.e. --src dir): source is a local directory path (e.g.: /media/usb/). Refer to skopeo(1) dir:path for the local image format.
- yaml (i.e. --src yaml): source is local YAML file path.
The YAML file should specify the list of images copied from different container registries (local directories are not supported). Refer to Examples for the file format.
Available destination transports:
- docker (i.e. --dest docker): destination is a container registry (e.g.: my-registry.local.lan).
- dir (i.e. --dest dir): destination is a local directory path (e.g.: /media/usb/).
One directory per source 'image:tag' is created for each copied image.
When the --scoped option is specified, images are prefixed with the source image path so that multiple images with the same name can be stored at destination.
Options
See also skopeo(1) for options placed before the subcommand name.
- --all, -a
- If one of the images in src refers to a list of images, instead of copying just the image which matches the current OS and architecture (subject to the use of the global --override-os, --override-arch and --override-variant options), attempt to copy all of the images in the list, and the list itself.
- --authfile path
- Path of the authentication file. Default is ${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.
- --src-authfile path
- Path of the authentication file for the source registry. Uses path given by --authfile, if not provided.
- --dest-authfile path
- Path of the authentication file for the destination registry. Uses path given by --authfile, if not provided.
- --dry-run
- Run the sync without actually copying data to the destination.
- --src, -s transport
- Transport for the source repository.
- --dest, -d transport
- Destination transport.
- --format, -f manifest-type
- Manifest Type (oci, v2s1, or v2s2) to use when syncing image(s) to a destination (default is manifest type of source, with fallbacks).
- --help, -h
- Print usage statement.
- --scoped
- Prefix images with the source image path, so that multiple images with the same name can be stored at destination.
- --append-suffix tag-suffix
- String to append to destination tags.
- --preserve-digests
- Preserve the digests during copying. Fail if the digest cannot be preserved.
This option does not change what will be copied; consider using --all at the same time.
- --remove-signatures
- Do not copy signatures, if any, from source-image. This is necessary when copying a signed image to a destination which does not support signatures.
- --sign-by key-id
- Add a “simple signing” signature using that key ID for an image name corresponding to destination-image
- --sign-by-sigstore param-file
- Add a sigstore signature based on the options in the specified containers sigstore signing parameter file, param-file. See containers-sigstore-signing-params.yaml(5) for details about the file format.
- --sign-by-sigstore-private-key path
- Add a sigstore signature using a private key at path for an image name corresponding to destination-image
- --sign-passphrase-file path
- The passphare to use when signing with --sign-by or --sign-by-sigstore-private-key. Only the first line will be read. A passphrase stored in a file is of questionable security if other users can read this file. Do not use this option if at all avoidable.
- --src-creds username[:password]
- for accessing the source registry.
- --dest-creds username[:password]
- for accessing the destination registry.
- --src-cert-dir path
- Use certificates (*.crt, *.cert, *.key) at path to connect to the source registry or daemon.
- --src-no-creds
- Access the registry anonymously.
- --src-tls-verify=bool
- Require HTTPS and verify certificates when talking to a container source registry or daemon. Default to source registry entry in registry.conf setting.
- --dest-cert-dir path
- Use certificates (*.crt, *.cert, *.key) at path to connect to the destination registry or daemon.
- --dest-no-creds
- Access the registry anonymously.
- --dest-tls-verify=bool
- Require HTTPS and verify certificates when talking to a container destination registry or daemon. Default to destination registry entry in registry.conf setting.
- --src-registry-token Bearer token
- for accessing the source registry.
- --dest-registry-token Bearer token
- for accessing the destination registry.
- --retry-times
- the number of times to retry, retry wait time will be exponentially increased based on the number of failed attempts.
- --keep-going
- If any errors occur during copying of images, those errors are logged and the process continues syncing rest of the images and finally fails at the end.
- --src-username
- The username to access the source registry.
- --src-password
- The password to access the source registry.
- --dest-username
- The username to access the destination registry.
- --dest-password
- The password to access the destination registry.
Examples
Synchronizing to a local directory
$ skopeo sync --src docker --dest dir registry.example.com/busybox /media/usb
Images are located at:
/media/usb/busybox:1-glibc /media/usb/busybox:1-musl /media/usb/busybox:1-ubuntu /media/usb/busybox:latest
Synchronizing to a container registry from local
Images are located at:
/media/usb/busybox:1-glibc
Sync run
$ skopeo sync --src dir --dest docker /media/usb/busybox:1-glibc my-registry.local.lan/test/
Destination registry content:
REPO TAGS my-registry.local.lan/test/busybox 1-glibc
Synchronizing to a local directory, scoped
$ skopeo sync --src docker --dest dir --scoped registry.example.com/busybox /media/usb
Images are located at:
/media/usb/registry.example.com/busybox:1-glibc /media/usb/registry.example.com/busybox:1-musl /media/usb/registry.example.com/busybox:1-ubuntu /media/usb/registry.example.com/busybox:latest
Synchronizing to a container registry
$ skopeo sync --src docker --dest docker registry.example.com/busybox my-registry.local.lan
Destination registry content:
REPO TAGS registry.local.lan/busybox 1-glibc, 1-musl, 1-ubuntu, ..., latest
Synchronizing to a container registry keeping the repository
$ skopeo sync --src docker --dest docker registry.example.com/repo/busybox my-registry.local.lan/repo
Destination registry content:
REPO TAGS registry.local.lan/repo/busybox 1-glibc, 1-musl, 1-ubuntu, ..., latest
Synchronizing to a container registry with tag suffix
$ skopeo sync --src docker --dest docker --append-suffix '-mirror' registry.example.com/busybox my-registry.local.lan
Destination registry content:
REPO TAGS registry.local.lan/busybox 1-glibc-mirror, 1-musl-mirror, 1-ubuntu-mirror, ..., latest-mirror
YAML file content (used source for **--src yaml**)
registry.example.com: images: busybox: [] redis: - "1.0" - "2.0" - "sha256:0000000000000000000000000000000011111111111111111111111111111111" images-by-tag-regex: nginx: ^1\.13\.[12]-alpine-perl$ images-by-semver: alpine: ">= 3.12.0" credentials: username: john password: this is a secret tls-verify: true cert-dir: /home/john/certs quay.io: tls-verify: false images: coreos/etcd: - latest
If the yaml filename is sync.yml, sync run:
$ skopeo sync --src yaml --dest docker sync.yml my-registry.local.lan/repo/
This will copy the following images: - Repository registry.example.com/busybox: all images, as no tags are specified. - Repository registry.example.com/redis: images tagged "1.0" and "2.0" along with image with digest "sha256:0000000000000000000000000000000011111111111111111111111111111111". - Repository registry.example.com/nginx: images tagged "1.13.1-alpine-perl" and "1.13.2-alpine-perl". - Repository quay.io/coreos/etcd: images tagged "latest". - Repository registry.example.com/alpine: all images with tags match the semantic version constraint ">= 3.12.0" ("3.12.0, "3.12.1", ... ,"4.0.0", ...)
The full list of possible semantic version comparisons can be found in the upstream library's documentation: https://github.com/Masterminds/semver/tree/v3.2.0#basic-comparisons.
Version ordering and precedence is understood as defined here: https://semver.org/#spec-item-11.
For the registry registry.example.com, the "john"/"this is a secret" credentials are used, with server TLS certificates located at /home/john/certs.
TLS verification is normally enabled, and it can be disabled setting tls-verify to false. In the above example, TLS verification is enabled for registry.example.com, while is disabled for quay.io.
See Also
skopeo(1), skopeo-login(1), docker-login(1), containers-auth.json(5), containers-policy.json(5), containers-transports(5)
Authors
Flavio Castelli fcastelli@suse.com ⟨mailto:fcastelli@suse.com⟩, Marco Vedovati mvedovati@suse.com ⟨mailto:mvedovati@suse.com⟩