A good basic intro. A "circuit breaker" is discussed as independent of the load balancer. Often those functions are combined. How does the load balancer detect when one of its resources has gone down? Or is overloaded and just slow. And how do you keep the load balancer from being a single point of failure?

Not much mention of whether requests are idempotent. Some things you don't want to retry, like payments.

Are you retrying to use different resources? Or in hopes the same resource will come back up? Those imply different strategies. Older telephony systems tried one retry with different resources, then gave up. If a call had failed twice, it probably wasn't a transient problem.