Thank you for [mentioning] Happy Eyeballs, but as I read in the current
RFC https://tools.ietf.org/html/rfc8305 , it will select the best entry
until you get a connection, not if the server responds slowly after a an
established connection. So I assume Happy Eyeballs is not real
Could the browser do a switchover for DNS Loadbalancing, if he knew
about the load or number of connections?
My best guess would be:
If the webserver provided a value of load (response HTTP-Header) to the
client, the client could use another DNS entry, depending on a global
The easiest way would be to send the systemload to the browser, when
this value is over 1, the browser should try another entry from DNS for
the next request.
PS: Of course webservers could implement fancy algorithms to manage
their clusters (evacuation etc.). And a stressed webserver could
recommend a specific entry, which the browser should consider (verifying
against DNS entry).