Wouldn't more modern implementations like EMQx be better suited for HA ?

To preface, I'm not a Kubernetes or Mosquitto expert by any means.

I'm confused about one point. A k8s Service sends traffic to pods matching the selector that are in "Ready" state, so wouldn't you accomplish HA without the pseudocontroller by just putting both pods in the Service? The Mosquitto bridge mechanism is bi-directional so you're already getting data re-sync no matter where a client writes.

edit: I'm also curious if you could use a headless service and use an init container on the secondary to set up the bridge to the primary by selecting the IP that isn't it's own.

when dealing with long lasting TCP connections, why add that extra layer of network complexity with k8s? I work for a big IoT company and we have 1.8M connections spread across 15 ec2 c8g.xlarge boxes. Not even using a NLB just round-robin DNS. Wrote our own broker with https://github.com/lesismal/nbio and use a packer .hcl file to make the AMI that each ec2 box boots. Using https://github.com/lesismal/llib/tree/master/std/crypto/tls to make nbio work with TLS.