README.md

Cluster Autoscaler (VMSS) Add-on

Cluster Autoscaler is a tool that automatically adjusts the size of the Kubernetes cluster when:

• there are pods that failed to run in the cluster due to insufficient resources.
• some nodes in the cluster are so underutilized, for an extended period of time, that they can be deleted and their pods will be easily placed on some other, existing nodes.

This is the Kubernetes Cluster Autoscaler add-on for Virtual Machine Scale Sets. Add this add-on to your json file as shown below to automatically enable cluster autoscaler in your new Kubernetes cluster.

To use this add-on, make sure your cluster's Kubernetes version is 1.10 or above and your agent pool availabilityProfile is set to VirtualMachineScaleSets. By default, the first agent pool will autoscale the node count between 1 and 5. You can override these settings in config section of the cluster-autoscaler add-on.

At this time, only the primaryScaleSet (the first agent pool) is monitored by the autoscaler. To configure autoscale to monitor (and scale) other node pools, you must manually edit the autoscaler YAML at /etc/kubernetes/addons on each master node. See the cluster-autoscaler docs for guidance.

The following is an example:

{
  "apiVersion": "vlabs",
  "properties": {
    "orchestratorProfile": {
      "orchestratorType": "Kubernetes",
      "orchestratorRelease": "1.10",
      "kubernetesConfig": {
        "useManagedIdentity": true,
        "addons": [
          {
            "name": "cluster-autoscaler",
            "enabled": true,
            "config": {
              "minNodes": "1",
              "maxNodes": "5"
            }
          }
        ]
      }
    },
    "masterProfile": {
      "count": 1,
      "dnsPrefix": "",
      "vmSize": "Standard_DS2_v2"
    },
    "agentPoolProfiles": [
      {
        "name": "agentpool",
        "count": 1,
        "vmSize": "Standard_DS2_v2",
        "availabilityProfile": "VirtualMachineScaleSets",
        "storageProfile": "ManagedDisks"
      }
    ],
    "linuxProfile": {
      "adminUsername": "azureuser",
      "ssh": {
        "publicKeys": [
          {
            "keyData": ""
          }
        ]
      }
    }
  }
}

You should see cluster autoscaler as running after running:

$ kubectl get pods -n kube-system

Follow the README at https://github.com/kubernetes/autoscaler/tree/master/cluster-autoscaler for more information.

Configuration

Name	Required	Description	Default Value
minNodes	no	minimum node count	1
maxNodes	no	maximum node count	5
name	no	container name	"cluster-autoscaler"
image	no	image	"gcr.io/google-containers/cluster-autoscaler"
cpuRequests	no	cpu requests for the container	"100m"
memoryRequests	no	memory requests for the container	"300Mi"
cpuLimits	no	cpu limits for the container	"100m"
memoryLimits	no	memory limits for the container	"300Mi"

Supported Orchestrators

• Kubernetes