Research Feasibility to Replace Lieutenant Operator by Crossplane

[tobru]

Context

Crossplane has matured a lot since we started with Lieutenant Operator. Since the introduction of the Composition feature it might be possible to completely replace Lieutenant Operator by Crossplane, shipping Compositions and Providers as part of Project Syn to enable the core features needed by the project.

Lieutenant Operator provides three objects:

• Tenant and Cluster: Both contain some information and the operator generate a GitRepo object out of them.
• GitRepo: Manages git repositories on GitLab and files in it.

All these objects could be replaced by XRDs and Compositions.

We should research the detail functionality which we would need and how it could be done with Crossplane. This research should help to decide if it's feasible to replace the Lieutenant Operator.

Upsides:

• No software maintenance needed anymore
• Integrating in a growing ecosystem, leveraging the community
• Being the "Configuration Management" system for Crossplane

Downside:

• "Vendor" lock-in to Crossplane
• Quite some effort