welp, not sure what docker changed but the frontend loadbalancer can't see any of the backend services right now for whatever reason.
standby, we're working on it
yea, everything is fine now.
post mortem:
I think what happened, is that after the reboot, docker-gen ran before things settled, working with stale information somehow and creating a bad config with addresses nginx couldn't reach, and then got confused somehow.
.... after repeatedly restarting the frontend loadbalancer it now suddenly connects to the containers again.
looks like things are working? but I'm keeping an eye on it
still investigating. it's very strange, the backend network is there, all the containers are in it, yet none of the services appear to be reachable from the frontend loadbalancer?
istg if fundamental tools could stop radically changing every update that'd be really swell