> As you can see, all clients correctly detect it and choose an alternative server.
This is the nasty key point. The reliability is decided client-side.
For example, systemd-resolved at times enacted maximum technical correctness by always returning the lowest IP address. After all, DNS-RR is not well-defined, so always returning the lowest IPs is not wrong. It got changed after some riots, but as far as I know, Debian 11 is stuck with that behavior, or was for a long time.
Or, I deal with many applications with shitty or no retry behavior. They go "Oh no, I have one connection refused, gotta cancel everything, shutdown, never try again". So now 20% - 30% of all requests die in a fire.
It's an acceptable solution if you have nothing else. As the article notices, if you have quality HTTP clients with a few retries configured on them (like browsers), DNS-RR is fine to find an actual load balancer with health checks and everything, which can provide a 100% success rate.
But DNS-RR is no loadbalancer and loadbalancers are better.
This is the nasty key point. The reliability is decided client-side.
For example, systemd-resolved at times enacted maximum technical correctness by always returning the lowest IP address. After all, DNS-RR is not well-defined, so always returning the lowest IPs is not wrong. It got changed after some riots, but as far as I know, Debian 11 is stuck with that behavior, or was for a long time.
Or, I deal with many applications with shitty or no retry behavior. They go "Oh no, I have one connection refused, gotta cancel everything, shutdown, never try again". So now 20% - 30% of all requests die in a fire.
It's an acceptable solution if you have nothing else. As the article notices, if you have quality HTTP clients with a few retries configured on them (like browsers), DNS-RR is fine to find an actual load balancer with health checks and everything, which can provide a 100% success rate.
But DNS-RR is no loadbalancer and loadbalancers are better.