[Pilot phase] Enable managing releases with the file-based catalog for Red Hat Operator teams with RHTAP

Feature Overview (aka. Goal Summary)  

Enable Red Hat Operator authors to manage Operator releases with FBC declaratively with RHTAP. 

Goals (aka. expected user outcomes)

• Red Hat Operator authors can manage Operator releases with RHTAP declaratively in a canonical source of truth and automated via git in the context of the OpenShift release.

• Existing catalog images in sqlite format can be converted to the basic template of file-based catalog (FBC) for easy adoption.

• (stretch goal) Red Hat Operator authors can mark a channel as deprecated and provide a replacement channel by name in the FBC template and stored in catalog metadata.

• (stretch goal) Existing catalog image in sqlite format can be converted to the semver template of file-based catalog (FBC) when possible and/or highlights the uncompleted sections so users can easier identify the gaps.

Requirements (aka. Acceptance Criteria):

Use Cases (Optional):

• Red Hat Operator teams can manage releases (i.e., edit the update paths) in a canonical source of truth (in FBC) and automate it via git to simplify the bundle release process with RHTAP.

• Red Hat Operator teams can mange and publish Operator releases from a canonical source of truth (in FBC) to multiple OCP versions with RHTAP.

• Operator authors/release managers can mark a channel as deprecated and provide a replacement channel statically by name in the FBC template and being stored in FBC metadata.

• stretch: Operator authors/release managers can convert their existing catalog images in sqlite format to the semver template of file-based catalog (FBC), when possible to drive adoption, and/or highlights the uncompleted sections so users can easier identify the gaps.

Background

This is the Pilot phase/scope of enabling file-based catalog (FBC) in RHTAP for Red Hat Operator teams.  For the overall scope of FBC feature, please see OCPBU-146.

The ultimate goal from the business standpoint is to make releasing Operators to OpenShift becomes a lot easier.  This is critical to support Red Hat in positioning "OpenShift as a Complete Platform" to differentiate against other k8s offerings in the market. Context:

• All OpenShift Layered Components and a broad partner ecosystem are shipped and managed by individual Operators.
• The ability for customers to enhance the value of their OpenShift clusters by installing these layered addons is how OpenShift wins the platform from most of our customer's stories --> this is so important to retain our competitive edge.

With the powerful new technologies in file-based catalogs (FBC) and catalog templates, the next important step is to put those into practice and start making impacts. Specifically, we want to implement this with a phased approach:

• Start with the Pilot phase: one to two target Operator teams. 
  • Continue working with the RHTAP team so that the interested Operator teams can try out FBC and these templates (and we can iterate and improve based on the feedback).

• Finish composite template: generate an FBC contribution for multiple catalogs (e.g., targeting multiple OCP releases).
  • Continue integrating the composite template to RHTAP  so an Operator team can have a single source for all the update graphs and publish them to multiple OCP releases at once.

• Provide an automated process/formulary for catalog updates on new bundle publish for easy adoption. 
  • Drive the adoption of FBC among our Operator ecosystem, including partners who manage and build their own custom catalogs.

• Allow Operator authors to mark a channel as deprecated and provide a replacement channel with FBC/catalog template
  • Help Operator teams to adopt semver template by aligning their current channel strategy to stable, fast, or candidate channels, in OpenShift fashion.

Customer Considerations

Red Hat Operator teams, "CNV Operator" as the 1st customer and "Serverless Operator" coming up next.

Documentation Considerations

• The way "to automate the catalog update process in FBC with newly-published bundle references" needs to be documented (in the context of "Developing Operators").

• The way "to publish Operator releases in the file-based catalog (FBC) to multiple OCP releases" needs to be documented (in the context of "Developing Operators" and "Administrator Tasks").

• The way "to convert existing catalog from sqlite database to file-based catalog (FBC) basic template" needs to be documented (in the context of "Developing Operators").

• The way "to mark a channel as deprecated and provide a replacement channel with FBC template and being stored in FBC metadata" needs to be documented (in the context of "Developing Operators").