mirror of https://github.com/kubernetes/kops.git
59 lines
2.9 KiB
Markdown
59 lines
2.9 KiB
Markdown
# Horizontal Pod Autoscaling
|
|
|
|
With Horizontal Pod Autoscaling, Kubernetes automatically scales the number of
|
|
pods in a replication controller, deployment, or replica set based on observed
|
|
CPU utilization (or, with alpha support, on some other, application-provided
|
|
metrics).
|
|
|
|
The current stable version, which only includes support for CPU autoscaling, can
|
|
be found in the `autoscaling/v1` API version. The alpha version, which includes
|
|
support for scaling on memory and custom metrics, can be found in
|
|
`autoscaling/v2beta1` (and `autoscaling/v2beta2` in 1.12 and later).
|
|
|
|
kOps can assist in setting up HPA. Relevant reading you will need to go through:
|
|
|
|
* [Extending the Kubernetes API with the aggregation layer][k8s-extend-api]
|
|
* [Configure The Aggregation Layer][k8s-aggregation-layer]
|
|
* [Horizontal Pod Autoscaling][k8s-hpa]
|
|
|
|
While the above links go into details on how Kubernetes needs to be configured
|
|
to work with HPA, a lot of that work is already done for you by kOps.
|
|
Specifically:
|
|
|
|
* [x] Enable the [Aggregation Layer][k8s-aggregation-layer] via the following
|
|
kube-apiserver flags:
|
|
* [x] `--requestheader-client-ca-file=<path to aggregator CA cert>`
|
|
* [x] `--requestheader-allowed-names=aggregator`
|
|
* [x] `--requestheader-extra-headers-prefix=X-Remote-Extra-`
|
|
* [x] `--requestheader-group-headers=X-Remote-Group`
|
|
* [x] `--requestheader-username-headers=X-Remote-User`
|
|
* [x] `--proxy-client-cert-file=<path to aggregator proxy cert>`
|
|
* [x] `--proxy-client-key-file=<path to aggregator proxy key>`
|
|
* [x] Enable [Horizontal Pod Scaling][k8s-hpa] ... set the appropriate flags for
|
|
`kube-controller-manager`:
|
|
* [x] `--horizontal-pod-autoscaler-use-rest-clients` should be true.
|
|
* [x] `--kubeconfig <path-to-kubeconfig>`
|
|
|
|
## Cluster Configuration
|
|
|
|
### Support For Multiple Metrics
|
|
|
|
To enable the resource metrics API for scaling on CPU and memory, install metrics-server
|
|
([installation instruction here][k8s-metrics-server]). The
|
|
compatibility matrix is as follows:
|
|
|
|
Metrics Server | Metrics API group/version | Supported Kubernetes version
|
|
---------------|---------------------------|-----------------------------
|
|
0.3.x | `metrics.k8s.io/v1beta1` | 1.8+
|
|
|
|
### Support For Custom Metrics
|
|
|
|
To enable the custom metrics API, register it via the API aggregation layer. If you're using
|
|
Prometheus, checkout the [custom metrics adapter for Prometheus][k8s-prometheus-custom-metrics-adapter].
|
|
|
|
[k8s-aggregation-layer]: https://kubernetes.io/docs/tasks/access-kubernetes-api/configure-aggregation-layer/
|
|
[k8s-extend-api]: https://kubernetes.io/docs/concepts/extend-kubernetes/api-extension/apiserver-aggregation/
|
|
[k8s-hpa]: https://kubernetes.io/docs/tasks/run-application/horizontal-pod-autoscale/
|
|
[k8s-metrics-server]: https://github.com/kubernetes/kops/blob/master/addons/metrics-server/README.md
|
|
[k8s-prometheus-custom-metrics-adapter]: https://github.com/DirectXMan12/k8s-prometheus-adapter
|