Man page - umoci-raw-runtime-config(1)

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Manual

umoci-raw-runtime-config(1)

NAME
SYNOPSIS
DESCRIPTION
OPTIONS
EXAMPLE
SEE ALSO

Aleksa Sarai DECEMBER 2016

NAME

umoci raw runtime-config - Generate an OCI runtime configuration for an image

SYNOPSIS

umoci raw runtime-config --image = image [: tag ] [ --rootfs = rootfs ] [ --rootless ] config

umoci raw config --image = image [: tag ] [ --rootfs = rootfs ] [ --rootless ] config

DESCRIPTION

Generate a new OCI runtime configuration from an image, without extracting the rootfs of said image. The configuration is written to the path given by config , overwriting it if it exists already. This is one of the operations done by umoci-unpack (1) when generating the runtime bundle, but because of the overhead of extracting a root filesystem, umoci-unpack (1) is not practical to be used many times if the user doesn’t actually want to use the root filesystem. Some fields require a root filesystem as a "source of truth", and a source root filesystem can be specified using --rootfs . The other flags have the same effects as with umoci-unpack (1).

Note however that the output of umoci-raw-runtime-config (1) is not necessarily identical to the output from umoci-unpack (1). This is especially true if --rootfs is not specified, which results in umoci (1) leaving fields in the runtime spec to their defaults if computing their values would require using the root filesystem as a source-of-truth.

OPTIONS

The global options are defined in umoci (1).

--image = image [: tag ]
The OCI image tag which will be extracted to the bundle . image must be a
path to a valid OCI image and tag must be a valid tag in the image. If
tag is not provided it defaults to "latest".

--rootfs = rootfs
Use rootfs as a secondary source of truth when generating the runtime
configuration (this is especially important for Config.User conversion). If
unspecified, any runtime fields that require a secondary source of truth to
be filled with be left in their default values. This may result in
discrepancies between the output of umoci-unpack (1) and
umoci-raw-runtime-config (1).

--rootless
Generate a rootless container configuration, similar to the configuration
produced by umoci-unpack (1) when provided the --rootless flag.

EXAMPLE

The following downloads an image from a docker (1) registry using skopeo (1) and then generates the config.json for that image.

% skopeo copy docker://opensuse/amd64:42.2 oci:image:latest
% umoci raw runtime-config --image image:latest config.json

If a root filesystem is already present, it is possible to specify it with the --rootfs flag. This will source the root filesystem for conversion operations that necessitate it.

% skopeo copy docker://opensuse/amd64:42.2 oci:image:latest
# umoci unpack --image image bundle
% umoci raw runtime-config --image image --rootfs bundle/rootfs config.json