Specification of signatures.json

Goal

This file should contain the data which is used by a program to recognize with a general algorithm which operating system an ISO image passes to the program. This specification should not be limited itself to one operating system. If that this is not possible, we shall focus on Linux and its distributions.

File structure

The file should be a single JSON object which has a single key with the name breeds. This key should contain a single sub-object with key-value pairs for each operating system group.

Currently the following operating system groups are existing:

• redhat

• debian

• ubuntu

• suse

• vmware

• freebsd

• xen

• unix

• windows

• powerkvm

• generic

This list should be modified when new groups are added, removed or changed when changed in the JSON.

Each of these operating system groups have a key for each version of it. The key should be in lowercase and should have a version suffix. The name of the key should be unique across the distribution section and contains an object.

For a list of keys and types please look at our schema: https://github.com/cobbler/libcobblersignatures/tree/main/docs/schema.json

Note

The schema is used to validate the signatures and can be used as a template for writing and comparing your own signatures. For more information read the JSON Schema documentation at https://json-schema.org/

Note

The current json type null is only valid for version_file_regex and kernel_arch_regex. For all other keys please use empty strings, lists or dicts for default values.

Version keys

Each operating system version object supports the following keys. This table is generated from the docstrings of libcobblersignatures.models.osversion.Osversion by scripts/sync_json_spec_docs.py — update the docstrings, then re-run the script, rather than editing the table below directly.

signatures.json version keys

Key	Type	Description
signatures	array	One or more paths, relative to the root of the ISO, whose existence identifies this OS version.
version_file	string / null	The regular expression which points to the file with the os-version info.
version_file_regex	string / null	The regular expression matched against the contents of the file located via version_file to confirm this version.
kernel_arch	string	The regular expression which tells Cobbler where to look for the architecture of the operating system. In some cases this may also be a path to the file where Cobbler should look for the architecture.
kernel_arch_regex	string / null	The regex applied within the file located via kernel_arch when it doesn’t point to the architecture directly.
supported_arches	array	The architectures Cobbler considers valid when detecting the architecture of an imported distro.
supported_repo_breeds	array	The repository breeds Cobbler may auto-create when it finds a matching repo in the install tree.
kernel_file	string	The regular expression to match to find the kernel.
initrd_file	string	The regular expression to match to find the initrd.
isolinux_ok	boolean	Whether directories named isolinux should still be scanned for a kernel/initrd pair instead of being skipped.
default_autoinstall	string	The filename for the default autoinstall template in Cobbler.
kernel_options	string	Default kernel options to apply to the imported ISO.
kernel_options_post	string	Default kernel post options to apply to the imported ISO.
template_files	string	Extra files merged into the imported distro’s template_files, used to render templated boot files (e.g. ESXi’s boot.cfg).
boot_files	array	Extra files, beyond the kernel and initrd, that must be copied out of the source tree and templated for the distro.
boot_loaders	object	The boot loaders Cobbler considers valid for this OS version, keyed by architecture.

Example files

Please have a look at https://github.com/cobbler/libcobblersignatures/tree/main/libcobblersignatures/config/distro_signatures.json

The most simple valid (but useless) signatures.json file will be:

{
  "breeds": {}
}