OCP/Telco Definition of Done
Epic Template descriptions and documentation.

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Epic Goal

• Implement a fallback mechanism to assign a host role (based on hostname ?) when MAC addresses are not provided or can not be provided in agent-config.yaml, such as in the case of OCI

Why is this important?

• Oracle Cloud Infrastructure (OCI) imposes a unique limitation wherein the MAC addresses of instances cannot be predetermined. This creates challenges for certain operations, such as assigning host roles in an agent-based installer. Typically, the agent-config.yaml file uses host details like MAC addresses for these assignments.
• When host roles are not explicitly defined in the agent-config.yaml, the default role assignment mechanism adheres to OpenShift Container Platform (OCP) guidelines. According to the documented automatic role selection process, the system aims to assign the control plane roles to the three weakest hosts that meet the minimum hardware requirements for control plane nodes. https://docs.redhat.com/en/documentation/assisted_installer_for_openshift_container_platform/2024/html/installing_openshift_container_platform_with_the_assisted_installer/assembly_role-assignment#con_auto-assign-role_role-assignment 
• Given this constraint, a valid and unique hostname for each instance could become a viable alternative to ensure that host roles can be effectively assigned. By leveraging hostnames, the system can bypass the need for MAC addresses and still maintain the integrity of host role assignments, enabling smooth functionality of the agent-based installer.
• By enabling a fallback mechanism that could use the hostname for role determination, deployments on OCI become more streamlined. Hostnames are already available in the agent-config.yaml, providing a viable alternative to MAC address-based matching. This approach ensures flexibility, simplifies configuration management, and centralizes host-specific configurations in a single location.
• Additionally, this implementation allows generic host identification mechanisms, improving support for OCI and other cloud environments with similar limitations.

Key Points:

1. Challenge: Lack of pre-determined MAC addresses in OCI instances.
2. Solution: Use valid, unique hostnames in the agent-config.yaml file.
3. Impact: Simplifies host role assignments while ensuring compatibility with OCI's environment.

Scenarios

1. Fallback to Hostname Matching

• • Given: OCI instances where MAC addresses are not available in agent-config.yaml.
  • When: A hostname is defined and associated with a host 
  • Then: The hostname is used to assign roles and other configurations, such as root device hints or static networking.

Acceptance Criteria

• CI - MUST be running successfully with tests automated
• Release Technical Enablement - Provide necessary release enablement details and documents.
• ...

Dependencies (internal and external)

1. ...

Previous Work (Optional):

1. …

Open questions::

1. OCI instances support the use of custom cloud-init scripts, which can automate configuration tasks at instance initialization. Could leveraging cloud-init scripts to generate and assign a UUID to each instance be a scalable and flexible approach to uniquely identify and configure hosts in agent-based installations?

Done Checklist

• CI - CI is running, tests are automated and merged.
• Release Enablement <link to Feature Enablement Presentation>
• DEV - Upstream code and tests merged: <link to meaningful PR or GitHub Issue>
• DEV - Upstream documentation merged: <link to meaningful PR or GitHub Issue>
• DEV - Downstream build attached to advisory: <link to errata>
• QE - Test plans in Polarion: <link or reference to Polarion>
• QE - Automated tests merged: <link or reference to automated tests>
• DOC - Downstream documentation merged: <link to meaningful PR>