[tor-dev] Scalability or Onionbalance for v3 ephemeral/ADD_ONION services

[Chad Retz]

A quick glance at the code shows that ADD_ONION (i.e. "ephemeral"
onion services) doesn't support setting an Onionbalance
frontend/master onion address (specifically
https://gitlab.torproject.org/tpo/core/tor/-/issues/32709 doesn't seem
to have a control-side analogue). Would a feature request for adding a
`*(SP "OnionbalanceMasterKey=" OBKey)` (or "OBMasterKey" or whatever)
to ADD_ONION be reasonable? If so, just add in Gitlab?

Also curious alternative scalability and load balancing options for
ephemeral v3 onion services. I have read
https://www.benthamsgaze.org/wp-content/uploads/2015/11/sucu-torscaling.pdf
but unsure if anything more recent has been written. Beyond that and
Onionbalance, any other interesting approaches I could employ
(assuming I can dev anything from a control port pov, but am wanting
to work w/ an unmodified Tor binary)?

Thanks,
Chad