Data from the above-sea-level UI (in the SaaS) can be passed to the unconfigured-ignition in the form of the InfraEnv. We need to populate this information into assisted-service. Ideally this should use the same mechanism as in the non-interactive flow, which is the agent-register-infraenv.service service.

One challenge with this is that in the non-interactive flow, the Cluster object is created prior to the InfraEnv (by the agent-register-cluster.service service), but in the interactive flow the Cluster is created by the UI once the user has entered some basic data like the name. agent-register-infraenv will need to poll the API until the Cluster exists, and then go ahead and create the InfraEnv. After the UI creates the Cluster, it will want to pause until it sees an InfraEnv created, then pre-load the data into its UI fields.

We can use late binding to solve this problem. agent-register-infraenv can register an InfraEnv not bound to a Cluster. The UI would create only the Cluster object, and not the InfraEnv. It would read default values for the SSH public key, proxy, and pull secret from the existing InfraEnv. The UI would need to bind all hosts it sees in the API to the Cluster. When deleting a cluster (to reset the configuration process to the beginning), the UI will need to unbind all the hosts first, and then delete only the Cluster (not the InfraEnv).