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Clarify version requirements for HPA docs
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Catherine Luse
@@ -5,9 +5,33 @@ weight: 3026
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Using the Kubernetes [Horizontal Pod Autoscaler](https://kubernetes.io/docs/tasks/run-application/horizontal-pod-autoscale/) feature (HPA), you can configure your cluster to automatically scale the services it's running up or down.
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Clusters created in Rancher v2.0.7 and higher have all the requirements needed (metrics-server and Kubernetes cluster configuration) to use Horizontal Pod Autoscaler.
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HPAs are handled differently based on your version of Rancher and your version of the Kubernetes API.
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You can create, manage, and delete HPAs using the Rancher UI in Rancher v2.3.0-alpha and higher versions. It only supports HPA in the `autoscaling/v2beta2` API.
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### For Kubernetes API version `autoscaling/V2beta1`
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This version of the Kubernetes API lets you autoscale your pods based on the CPU and memory utilization of your application.
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### For Kubernetes API Version `autoscaling/V2beta2`
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This version of the Kubernetes API lets you autoscale your pods based on CPU and memory utilization, in addition to custom metrics.
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### For Rancher v2.0.7+
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Clusters created in Rancher v2.0.7 and higher have all the requirements needed (metrics-server and Kubernetes cluster configuration) to use HPA.
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### For Rancher Prior to v2.0.7
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Clusters created in Rancher prior to v2.0.7 don't automatically have the requirements needed to use HPA. For instructions on installing HPA for these clusters, refer to [Manual HPA Installation for Clusters Created Before Rancher v2.0.7]({{< baseurl >}}/rancher/v2.x/en/k8s-in-rancher/horitzontal-pod-autoscaler/hpa-for-rancher-before-2_0_7).
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### For Rancher Prior to v2.3.0-alpha
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You can [manage HPAs using `kubectl`]({{< baseurl >}}/rancher/v2.x/en/k8s-in-rancher/horitzontal-pod-autoscaler/manage-hpa-with-kubectl).
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### For Rancher v2.3.0-alpha+
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You can create, manage, and delete HPAs using the Rancher UI. From the Rancher UI you can configure the HPA to scale based on CPU and memory utilization.
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For configuring HPA to scale based on custom metrics, you still need to use `kubectl`. For more information, refer to [Managing HPAs using `kubectl`]({{< baseurl >}}/rancher/v2.x/en/k8s-in-rancher/horitzontal-pod-autoscaler/manage-hpa-with-kubectl/_index.md)
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## Why Use Horizontal Pod Autoscaler?
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+188
@@ -0,0 +1,188 @@
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---
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title: Managing HPAs with kubectl
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weight: 3027
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---
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# Manual Installation for Clusters Created Before Rancher v2.0.7
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Before you can use HPA in your Kubernetes cluster, you must fulfill some requirements.
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### Requirements
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Be sure that your Kubernetes cluster services are running with these flags at minimum:
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- kube-api: `requestheader-client-ca-file`
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- kubelet: `read-only-port` at 10255
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- kube-controller: Optional, just needed if distinct values than default are required.
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- `horizontal-pod-autoscaler-downscale-delay: "5m0s"`
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- `horizontal-pod-autoscaler-upscale-delay: "3m0s"`
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- `horizontal-pod-autoscaler-sync-period: "30s"`
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For an RKE Kubernetes cluster definition, add this snippet in the `services` section. To add this snippet using the Rancher v2.0 UI, open the **Clusters** view and select **Ellipsis (...) > Edit** for the cluster in which you want to use HPA. Then, from **Cluster Options**, click **Edit as YAML**. Add the following snippet to the `services` section:
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```
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services:
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...
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kube-api:
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extra_args:
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requestheader-client-ca-file: "/etc/kubernetes/ssl/kube-ca.pem"
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kube-controller:
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extra_args:
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horizontal-pod-autoscaler-downscale-delay: "5m0s"
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horizontal-pod-autoscaler-upscale-delay: "1m0s"
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horizontal-pod-autoscaler-sync-period: "30s"
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kubelet:
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extra_args:
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read-only-port: 10255
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```
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Once the Kubernetes cluster is configured and deployed, you can deploy metrics services.
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>**Note:** `kubectl` command samples in the sections that follow were tested in a cluster running Rancher v2.0.6 and Kubernetes v1.10.1.
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### Configuring HPA to Scale Using Resource Metrics
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To create HPA resources based on resource metrics such as CPU and memory use, you need to deploy the `metrics-server` package in the `kube-system` namespace of your Kubernetes cluster. This deployment allows HPA to consume the `metrics.k8s.io` API.
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>**Prerequisite:** You must be running `kubectl` 1.8 or later.
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1. Connect to your Kubernetes cluster using `kubectl`.
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1. Clone the GitHub `metrics-server` repo:
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```
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# git clone https://github.com/kubernetes-incubator/metrics-server
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```
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1. Install the `metrics-server` package.
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```
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# kubectl create -f metrics-server/deploy/1.8+/
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```
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1. Check that `metrics-server` is running properly. Check the service pod and logs in the `kube-system` namespace.
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1. Check the service pod for a status of `running`. Enter the following command:
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```
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# kubectl get pods -n kube-system
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```
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Then check for the status of `running`.
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```
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NAME READY STATUS RESTARTS AGE
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...
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metrics-server-6fbfb84cdd-t2fk9 1/1 Running 0 8h
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...
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```
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1. Check the service logs for service availability. Enter the following command:
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```
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# kubectl -n kube-system logs metrics-server-6fbfb84cdd-t2fk9
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```
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Then review the log to confirm that the `metrics-server` package is running.
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{{% accordion id="metrics-server-run-check" label="Metrics Server Log Output" %}}
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I0723 08:09:56.193136 1 heapster.go:71] /metrics-server --source=kubernetes.summary_api:''
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I0723 08:09:56.193574 1 heapster.go:72] Metrics Server version v0.2.1
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I0723 08:09:56.194480 1 configs.go:61] Using Kubernetes client with master "https://10.43.0.1:443" and version
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I0723 08:09:56.194501 1 configs.go:62] Using kubelet port 10255
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I0723 08:09:56.198612 1 heapster.go:128] Starting with Metric Sink
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I0723 08:09:56.780114 1 serving.go:308] Generated self-signed cert (apiserver.local.config/certificates/apiserver.crt, apiserver.local.config/certificates/apiserver.key)
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I0723 08:09:57.391518 1 heapster.go:101] Starting Heapster API server...
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[restful] 2018/07/23 08:09:57 log.go:33: [restful/swagger] listing is available at https:///swaggerapi
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[restful] 2018/07/23 08:09:57 log.go:33: [restful/swagger] https:///swaggerui/ is mapped to folder /swagger-ui/
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I0723 08:09:57.394080 1 serve.go:85] Serving securely on 0.0.0.0:443
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{{% /accordion %}}
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1. Check that the metrics api is accessible from `kubectl`.
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- If you are accessing the cluster through Rancher, enter your Server URL in the `kubectl` config in the following format: `https://<RANCHER_URL>/k8s/clusters/<CLUSTER_ID>`. Add the suffix `/k8s/clusters/<CLUSTER_ID>` to API path.
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```
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# kubectl get --raw /k8s/clusters/<CLUSTER_ID>/apis/metrics.k8s.io/v1beta1
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```
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If the API is working correctly, you should receive output similar to the output below.
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```
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{"kind":"APIResourceList","apiVersion":"v1","groupVersion":"metrics.k8s.io/v1beta1","resources":[{"name":"nodes","singularName":"","namespaced":false,"kind":"NodeMetrics","verbs":["get","list"]},{"name":"pods","singularName":"","namespaced":true,"kind":"PodMetrics","verbs":["get","list"]}]}
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```
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- If you are accessing the cluster directly, enter your Server URL in the kubectl config in the following format: `https://<K8s_URL>:6443`.
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```
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# kubectl get --raw /apis/metrics.k8s.io/v1beta1
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```
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If the API is working correctly, you should receive output similar to the output below.
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```
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{"kind":"APIResourceList","apiVersion":"v1","groupVersion":"metrics.k8s.io/v1beta1","resources":[{"name":"nodes","singularName":"","namespaced":false,"kind":"NodeMetrics","verbs":["get","list"]},{"name":"pods","singularName":"","namespaced":true,"kind":"PodMetrics","verbs":["get","list"]}]}
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```
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### Assigning Additional Required Roles to Your HPA
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By default, HPA reads resource and custom metrics with the user `system:anonymous`. Assign `system:anonymous` to `view-resource-metrics` and `view-custom-metrics` in the ClusterRole and ClusterRoleBindings manifests. These roles are used to access metrics.
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To do it, follow these steps:
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1. Configure `kubectl` to connect to your cluster.
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1. Copy the ClusterRole and ClusterRoleBinding manifest for the type of metrics you're using for your HPA.
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{{% accordion id="cluster-role-resource-metrics" label="Resource Metrics: ApiGroups resource.metrics.k8s.io" %}}
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apiVersion: rbac.authorization.k8s.io/v1
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kind: ClusterRole
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metadata:
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name: view-resource-metrics
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rules:
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- apiGroups:
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- metrics.k8s.io
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resources:
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- pods
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- nodes
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verbs:
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- get
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- list
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- watch
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---
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apiVersion: rbac.authorization.k8s.io/v1
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kind: ClusterRoleBinding
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metadata:
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name: view-resource-metrics
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roleRef:
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apiGroup: rbac.authorization.k8s.io
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kind: ClusterRole
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name: view-resource-metrics
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subjects:
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- apiGroup: rbac.authorization.k8s.io
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kind: User
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name: system:anonymous
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{{% /accordion %}}
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{{% accordion id="cluster-role-custom-resources" label="Custom Metrics: ApiGroups custom.metrics.k8s.io" %}}
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```
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apiVersion: rbac.authorization.k8s.io/v1
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kind: ClusterRole
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metadata:
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name: view-custom-metrics
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rules:
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- apiGroups:
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- custom.metrics.k8s.io
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resources:
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- "*"
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verbs:
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- get
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- list
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- watch
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---
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apiVersion: rbac.authorization.k8s.io/v1
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kind: ClusterRoleBinding
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metadata:
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name: view-custom-metrics
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roleRef:
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apiGroup: rbac.authorization.k8s.io
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kind: ClusterRole
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name: view-custom-metrics
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subjects:
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- apiGroup: rbac.authorization.k8s.io
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kind: User
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name: system:anonymous
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```
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{{% /accordion %}}
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1. Create them in your cluster using one of the follow commands, depending on the metrics you're using.
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```
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# kubectl create -f <RESOURCE_METRICS_MANIFEST>
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# kubectl create -f <CUSTOM_METRICS_MANIFEST>
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```
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