问题
The Kubernetes Horizontal Pod Autoscaler walkthrough in https://kubernetes.io/docs/tasks/run-application/horizontal-pod-autoscale-walkthrough/ explains that we can perform autoscaling on custom metrics. What I didn't understand is when to use the two API versions: v2beta1 and v2beta2. If anybody can explain, I would really appreciate it.
Thanks in advance.
回答1:
The first metrics autoscaling/V2beta1 doesn't allow you to scale your pods based on custom metrics. That only allows you to scale your application based on CPU and memory utilization of your application
The second metrics autoscaling/V2beta2 allows users to autoscale based on custom metrics. It allow autoscaling based on metrics coming from outside of Kubernetes. A new External metric source is added in this api.
metrics:
- type: Resource
resource:
name: cpu
target:
type: Utilization
averageUtilization: 50
It will identify a specific metric to autoscale on based on metric name and a label selector. Those metrics can come from anywhere like a stackdriver or prometheus monitoring application and based on some query from prometheus you want to scale your application.
It would always better to use V2beta2 api because it can do scaling on CPU and memory as well as on custom metrics, while V2beta1 API can scale only on internal metrics.
The snippet I mentioned in answer denotes how you can specify the target CPU utilisation in V2beta2 API
回答2:
Just like any other software product, k8 is also release new version with new feature. In k8, every object is specified with api version. With each new api version, k8 object get new features or additional capabilities.
So in case of HPA, beta2 has some more features than beta1 which are mentioned in documentation. So always remember to use stable release(exp. V1) if not available use latest release ( beta2 in case of HPA) for k8 object.
来源：https://stackoverflow.com/questions/54459447/difference-between-api-versions-v2beta1-and-v2beta2-in-horizontal-pod-autoscaler