Use data from /etc/os-release to identify the operating system

[poncovka]

Names of cloud images are not a reliable source of information when it comes to identifying the operating system. These names are not standardized across cloud providers or operating systems themselves (see #615). However, every Linux distribution provides the standardized /etc/os-release file that contains operating system identification data. For example:

NAME="Fedora Linux"
VERSION="37 (Workstation Edition)"
ID=fedora
VERSION_ID=37
VERSION_CODENAME=""
PLATFORM_ID="platform:f37"
PRETTY_NAME="Fedora Linux 37 (Workstation Edition)"
ANSI_COLOR="0;38;2;60;110;180"
LOGO=fedora-logo-icon
CPE_NAME="cpe:/o:fedoraproject:fedora:37"
DEFAULT_HOSTNAME="fedora"
HOME_URL="https://fedoraproject.org/"
DOCUMENTATION_URL="https://docs.fedoraproject.org/en-US/fedora/f37/system-administrators-guide/"
SUPPORT_URL="https://ask.fedoraproject.org/"
BUG_REPORT_URL="https://bugzilla.redhat.com/"
REDHAT_BUGZILLA_PRODUCT="Fedora"
REDHAT_BUGZILLA_PRODUCT_VERSION=37
REDHAT_SUPPORT_PRODUCT="Fedora"
REDHAT_SUPPORT_PRODUCT_VERSION=37
SUPPORT_END=2023-11-14
VARIANT="Workstation Edition"
VARIANT_ID=workstation

I think that Cloud Image Directory should use ID, VERSION_ID and VARIANT_ID in the API and extend the image data with NAME, VERSION, VARIANT and PRETTY_NAME. That would automatically take care of sorting cloud images by products and it would work by default for all cloud providers and Linux distributions provided by CID.

Drawbacks

• Getting the content of the /etc/os-release file from a cloud image probably requires to run an instance of this image. That can be expensive. However, the content of this file should be predictable and constant, so there should be some space for assumptions and heuristics, that can be later verified with image tests. Another option is to somehow integrate the collection of image data directly into the image tests that are going to be run anyway.

Benefits

• Cloud Image Directory uses standardized identifiers.
• It improves the credibility of the provided image data.
• It simplifies support for future cloud providers and products.
• It opens a window for collecting more data about cloud images (for example, the available software).