To split the traffic between two load balancers, doesn't there have to be a third load balancer to peform the splitting? Wouldn't this counter the idea of having two load balancers to prevent a single point of failure?
Load Balancing – Do Two Load Balancers Require a Third Load Balancer?
load balancing
Best Answer
There are many ways to spread load upstream of a loadbalancer. Two popular methods are DNS round robin and Anycast IPs.
DNS roundrobin involves having multiple records (I.e. each LB) for a given entry and having them returned in a round robin order. Thus the load is roughly spread across each load balancer. With that said, this is a naive approach and has a number of downsides.
Another option is to have any anycast IP which routes to multiple loadbalancers within multiple datacenters. This is more complex to setup, but allows much more granular control.
Google published a great writeup here about global loadbalancing and the limitations of each approach: https://landing.google.com/sre/book/chapters/load-balancing-frontend.html