Great writeup on the core fundamentals, saved this to share with engineers who are new to k8s and need a quick primer.
Re: This piece -
> Given the Controller pattern, why isn't there support for "Cloud Native" architectures?
> I would like to have a ReplicaSet which scales the replicas based on some simple calculation for queue depth (eg: queue depth / 16 = # replicas)
> Defining interfaces for these types of events (queue depth, open connections, response latency) would be great
> Basically, Horizontal Pod Autoscaler but with sensors which are not just "CPU"
HPAs are actually still what you want here - you can configure HPAs to scale automatically based on custom metrics. If you run Prometheus (or a similar collector), you can define the metric you want (e.g. queue-depth) and the autoscaler will make scaling decisions with these in mind.
Resources:
https://kubernetes.io/docs/tasks/run-application/horizontal-...
https://learnk8s.io/autoscaling-apps-kubernetes
Re: This piece -
> Given the Controller pattern, why isn't there support for "Cloud Native" architectures?
> I would like to have a ReplicaSet which scales the replicas based on some simple calculation for queue depth (eg: queue depth / 16 = # replicas)
> Defining interfaces for these types of events (queue depth, open connections, response latency) would be great
> Basically, Horizontal Pod Autoscaler but with sensors which are not just "CPU"
HPAs are actually still what you want here - you can configure HPAs to scale automatically based on custom metrics. If you run Prometheus (or a similar collector), you can define the metric you want (e.g. queue-depth) and the autoscaler will make scaling decisions with these in mind.
Resources:
https://kubernetes.io/docs/tasks/run-application/horizontal-...
https://learnk8s.io/autoscaling-apps-kubernetes