Cluster Autoscaler

If you have not already done so, make sure your EKS Anywhere cluster meets the package prerequisites.

Refer to the troubleshooting guide in the event of a problem.

Enable Cluster Autoscaling

1. Ensure you have configured at least one worker node group in your cluster specification to enable autoscaling as outlined in Autoscaling configuration. Cluster Autoscaler only works on node groups with an autoscalingConfiguration set:

   apiVersion: anywhere.eks.amazonaws.com/v1alpha1
   kind: Cluster
   metadata:
     name: <cluster-name>
   spec:
     ...
     workerNodeGroupConfigurations:
       - autoscalingConfiguration:
           minCount: 1
           maxCount: 5
         machineGroupRef:
           kind: VSphereMachineConfig
           name: <worker-machine-config-name>
         count: 1
         name: md-0
   

2. Generate the package configuration.

   eksctl anywhere generate package cluster-autoscaler --cluster <cluster-name> > cluster-autoscaler.yaml
   

3. Add the desired configuration to cluster-autoscaler.yaml. See configuration options for all configuration options and their default values. See below for example package files configuring a Cluster Autoscaler package.

   For Management Cluster Autoscaling:

   apiVersion: packages.eks.amazonaws.com/v1alpha1
   kind: Package
   metadata:
     name: cluster-autoscaler-<cluster-name>
     namespace: eksa-packages-<cluster-name>
   spec:
     packageName: cluster-autoscaler
     targetNamespace: default
     config: |-
         cloudProvider: "clusterapi"
         autoDiscovery:
           clusterName: "<cluster-name>"      
   

   For Workload Cluster Autoscaling (deployed from Management Cluster):

   apiVersion: packages.eks.amazonaws.com/v1alpha1
   kind: Package
   metadata:
     name: cluster-autoscaler-<workload-cluster-name>
     namespace: eksa-packages-<management-cluster-name>
   spec:
     packageName: cluster-autoscaler
     targetNamespace: eksa-system
     config: |-
         cloudProvider: "clusterapi"
         clusterAPIMode: "kubeconfig-incluster"
         clusterAPIKubeconfigSecret: "<workload-cluster-name>-kubeconfig"
         autoDiscovery:
           clusterName: "<workload-cluster-name>"      
   

   Configuration Fields for Workload Cluster Autoscaling:

   • clusterAPIMode: Set to "kubeconfig-incluster" to enable workload cluster autoscaling from the management cluster
   • clusterAPIKubeconfigSecret: Name of the Kubernetes secret containing the kubeconfig for the workload cluster. EKS Anywhere automatically creates this secret in the management cluster with the naming pattern <workload-cluster-name>-kubeconfig
   • targetNamespace: Should be set to eksa-system for workload cluster autoscaling
   • autoDiscovery.clusterName: Must match the name of the workload cluster to be autoscaled

   Note: The kubeconfig secret for workload clusters is automatically created by EKS Anywhere in the management cluster when a workload cluster is provisioned. This secret provides the necessary credentials for the autoscaler running in the management cluster to manage the workload cluster’s nodes.

4. Install Cluster Autoscaler

   eksctl anywhere create packages -f cluster-autoscaler.yaml
   

5. Validate the installation

   eksctl anywhere get packages --cluster <cluster-name>
   

   NAMESPACE                  NAME                          PACKAGE              AGE   STATE       CURRENTVERSION                                               TARGETVERSION                                                         DETAIL
   eksa-packages-mgmt-v-vmc   cluster-autoscaler            cluster-autoscaler   18h   installed   9.21.0-1.21-147e2a701f6ab625452fe311d5c94a167270f365         9.21.0-1.21-147e2a701f6ab625452fe311d5c94a167270f365 (latest)
   

   To verify that autoscaling works, apply the deployment below. You must continue scaling pods until the deployment has pods in a pending state. This is when Cluster Autoscaler will begin to autoscale your machine deployment. This process may take a few minutes.

   kubectl apply -f https://raw.githubusercontent.com/aws/eks-anywhere/d8575bbd2a85a6c6bbcb1a54868cf7790df56a63/test/framework/testdata/hpa_busybox.yaml
   kubectl scale deployment hpa-busybox-test --replicas 100
   

Update

To update package configuration, update the cluster-autoscaler.yaml file and run the following command:

eksctl anywhere apply package -f cluster-autoscaler.yaml

Update Worker Node Group Autoscaling Configuration

It is possible to change the autoscaling configuration of a worker node group by updating the autoscalingConfiguration in your cluster specification and running a cluster upgrade.

Upgrade

The Cluster Autoscaler can be upgraded by PackageController’s activeBundle field to a newer version. The curated packages bundle contains the SHAs of the images and helm charts associated with a particular package. When a new version is activated, the Package Controller will reconcile all active packages to their newest versions as defined in the bundle. The Curated Packages Controller automatically polls the bundle repository for new bundle resources. The curated packages controller automatically polls for the latest bundle, but requires the activeBundle field on the PackageController resource to be updated before a new bundle will take effect and upgrade the resources.

Uninstall

To uninstall Cluster Autoscaler, delete the package

eksctl anywhere delete package --cluster <cluster-name> cluster-autoscaler