FB likes to break everything all at once anyway... And healtchecking the load balancers wasn't working either. So DNS to regional balancers was sending people t

FB likes to break everything all at once anyway... And healtchecking the load balancers wasn't working either. So DNS to regional balancers was sending people to the wrong place, and the anycast ips might have worked if you were lucky, but you might have gotten a PoP that was broken. The servers behind it were fine, if you could get to one. You could push broken DNS responses, I suppose, but it's harder than breaking a load balancer.