discover_latest_image

An Ansible role to discover latest Centos/RHEL image.

Requirements

This role is currently written for Centos and RHEL.

Role Variables

• cifmw_discover_latest_image_base_url: (String) Base Url from where we can pull the Centos Image. Defaults to <https://cloud.centos.org/centos/{{ ansible_distribution_major_version }}-stream/x86_64/images/.

• cifmw_discover_latest_image_qcow_prefix: (String) Qcow2 image prefix on base_url which will be used as a filter to find latest Centos Image. Defaults to CentOS-Stream-GenericCloud-.

• cifmw_discover_latest_image_images_file: (String) Name of the file that contain the images with the corresponding hash. Default: CHECKSUM. Check the IMAGES_FILES constant of the discover_latest_image.py plugin.

• cifmw_discover_latest_image_requests: (Dict) A collection of data used to discover the latest images from several sources. See the section on discovering multiple images. Default:

cifmw_discover_latest_image_requests:
  default:
    base_url: "{{ cifmw_discover_latest_image_base_url }}"
    qcow_prefix: "{{ cifmw_discover_latest_image_qcow_prefix }}"
    images_file: "{{ cifmw_discover_latest_image_images_file }}"

Discovering Multiple Images

This role can discover multiple images from multiple separate sources when provided the dict cifmw_discover_latest_image_requests. For multi-image discovery to work properly, it is required that this dict has the following schema:

cifmw_discover_latest_image_requests:
  some_name:
    base_url: ...
    qcow_prefix: ...
    images_file: ...
  some_other_name:
    base_url: ...
    qcow_prefix: ...
    images_file: ...

Each entry in the requests dict must have these 3 entries (base_url, qcow_prefix, and images_file) set. Assuming these conditions are met, and an image can be discovered for each provided base_url, qcow_prefix, and images_file, this role will set a fact called cifmw_discovered_images_dict with all of the data from the discovered images. Given the above requests dict, the resulting cifmw_discovered_images_dict would be:

cifmw_discovered_images_dict:
  some_name:
    hash: ...
    hash_algorithm: ...
    image_name: ...
    image_url: ...
  some_other_name:
    hash: ...
    hash_algorithm: ...
    image_name: ...
    image_url: ...

Every time the discover_latest_image role is called, the cifmw_discovered_images_dict is reset, and the single-image cifmw_discovered_[image_name,image_url,hash,hash_algorithm] facts are set to null, erasing any discovered image data that may exist from previous calls. Either call the role once with all of the image requests you intend to make, or be careful to manage the complete collection of discovered images yourself.

The default image

If the cifmw_discover_latest_image_requests dict has an entry named default, the default entry’s discovered hash, hash_algorithm, image_name, and image_url will be set as the cifmw_discovered_hash, cifmw_discovered_hash_algorithm, cifmw_discovered_image_name, and cifmw_discovered_image_url facts respectively.

It should be noted that the method of discovering a single image via the cifmw_discover_latest_image_[base_url,qcow_prefix,images_file] variables now works by putting those variables into the default entry of a single-entry cifmw_discover_latest_image_requests dict (see the cifmw_discover_latest_image_requests default value). This means that in single-image mode, this role not only sets the cifmw_discovered_* facts as expected, but also creates a cifmw_discovered_images_dict dict with a single default entry.

Examples

- name: Discover latest CentOS qcow2 image
  ansible.builtin.include_role:
    name: discover-latest-image

- name: Output discovered data
  ansible.builtin.debug:
    msg: "{{ cifmw_discovered_image_name }} - {{ cifmw_discovered_image_url }}"