Failover UI Configuration in Datum Cloud for Datum Desktop Tunnels

[bmertens-datum]

High-Level Summary

Add UI configuration in Datum Cloud to manage passive health checks and failover for Datum Desktop tunnels. When a tunnel becomes unavailable, traffic should automatically route to a configured fallback endpoint. All API and backend support already exists; this work is UI-only.

A clickable demo is available at https://datum.salon/. Go to Proxy -> New Proxy ->Configure-> Failover

Note: there are many failover configuration option that are in the API and the clickable UI demo. We should limit this to an easy to digest subset of configuration options.

Motivation

Datum Desktop tunnels are transient by nature. Laptops sleep, networks disconnect, and local services stop. When this happens, end users should be routed to a useful fallback instead of seeing errors or timeouts.

Goals

• Expose existing passive failover capabilities in the Datum Cloud UI
• Allow users to configure a fallback endpoint for tunnels
• Improve reliability of traffic routed through Datum Desktop tunnels

Non-Goals

• Any API or backend changes
• Active health checks
• Load balancing or traffic splitting

[bmertens-datum]

@zachsmith1 I am having a bit of trouble getting this one working with datumctl. I should have it sorted by the end of the week.