We will go bottom to top (from builder’s eyes to run through the above briefly:
Instance(s) : These are essentially PostgREST instances service attached to Postgres DB populated using cardano-db-sync. instance. Every consumer who is providing their own instance will be expected to serve at least a PostgREST instance, as this is what allows us to string instances together after health-checks. If using guild-operator setup instructions, these will be provisioned for you by setup scripts.
Health-Check Services : These are lightweight HAProxy instances that will be gatekeepers for individual endpoints, doing health-checks , sample data verification, etc. A builder may opt-in to run this monitoring service, and add their instance to github repository. Again, setting up HAProxy will be part of setup scripts on guild-operator’s repo for those interested.
DNS Routing : These will be the entry points from trusted instances that will route to health check proxy services. We will be using at least two DNS ourselves to not have single point of failure, but that does not limit users to elect any of the other server endpoints instead, since the API works right from the PostgREST layer itself.