Side note, I haven't heard failover used in the context of kicking unhealthy backends before. Failover is typically something that would be implemented with carp(4) (aka VRRP, but with support for active/active setups) on two different machines running relayd.
https://man.openbsd.org/man8/relayd.8
https://man.openbsd.org/man8/relayctl.8
https://man.openbsd.org/man5/relayd.conf.5
Side note, I haven't heard failover used in the context of kicking unhealthy backends before. Failover is typically something that would be implemented with carp(4) (aka VRRP, but with support for active/active setups) on two different machines running relayd.
https://man.openbsd.org/man4/carp.4
Nothing beats the sheer elegance of OpenBSD for networking tasks. :-)