@helm-charts/banzaicloud-stable-cluster-autoscaler v0.6.4-0.1.0

@helm-charts/banzaicloud-stable-cluster-autoscaler

Scales worker nodes within autoscaling groups.

autoDiscovery:
# Only cloudProvider `aws` and `gce` are supported by auto-discovery at this time
# AWS: Set tags as described in https://github.com/kubernetes/autoscaler/blob/master/cluster-autoscaler/cloudprovider/aws/README.md#auto-discovery-setup
  clusterName:  # cluster.local

autoscalingGroups: []
# At least one element is required if not using autoDiscovery
  # - name: asg1
  #   maxSize: 2
  #   minSize: 1
  # - name: asg2
  #   maxSize: 2
  #   minSize: 1

autoscalingGroupsnamePrefix: []
# At least one element is required if not using autoDiscovery
  # - name: ig01
  #   maxSize: 10
  #   minSize: 0
  # - name: ig02
  #   maxSize: 10
  #   minSize: 0

# Required if cloudProvider=aws
awsRegion: us-east-1

# Required if cloudProvider=azure
azure:
  vmType: AKS
  clientID:
  clientSecret:
  subscriptionID:
  tenantID:
  resourceGroup:
  nodeResourceGroup:
  clusterName:

# Currently only `gce`, `aws`, `azure`, `gke` & `spotinst` are supported
cloudProvider: aws

sslCertPath: /etc/ssl/certs/ca-certificates.crt

# Configuration file for cloud provider
cloudConfigPath: /etc/gce.conf

image:
  repository: banzaicloud/cluster-autoscaler
  tag: v1.2.2.1
  pullPolicy: IfNotPresent

tolerations: []

extraArgs:
  v: 4
  stderrthreshold: info
  logtostderr: true
  # write-status-configmap: true
  # leader-elect: true
  skip-nodes-with-local-storage: false
  expander: least-waste
  # scale-down-enabled: true
  # balance-similar-node-groups: true
  # min-replica-count: 2
  # scale-down-utilization-threshold: 0.5
  # scale-down-non-empty-candidates-count: 5
  # max-node-provision-time: 15m0s
  # scan-interval: 10s
  # scale-down-delay: 3m
  scale-down-unneeded-time: 3m
  skip-nodes-with-local-storage: false
  skip-nodes-with-system-pods: true

## Affinity for pod assignment
## Ref: https://kubernetes.io/docs/concepts/configuration/assign-pod-node/#affinity-and-anti-affinity
## affinity: {}

podDisruptionBudget: |
  maxUnavailable: 1
  # minAvailable: 2

## Node labels for pod assignment
## Ref: https://kubernetes.io/docs/user-guide/node-selection/
nodeSelector: {}

podAnnotations: {}
podLabels: {}
replicaCount: 1

rbac:
  ## If true, create & use RBAC resources
  ##
  create: false
  ## If true, create & use Pod Security Policy resources
  ## https://kubernetes.io/docs/concepts/policy/pod-security-policy/
  pspEnabled: false
  ## Ignored if rbac.create is true
  ##
  serviceAccountName: default

resources: {}
  # limits:
  #   cpu: 100m
  #   memory: 300Mi
  # requests:
  #   cpu: 100m
  #   memory: 300Mi

service:
  annotations: {}
  clusterIP: ""

  ## List of IP addresses at which the service is available
  ## Ref: https://kubernetes.io/docs/user-guide/services/#external-ips
  ##
  externalIPs: []

  loadBalancerIP: ""
  loadBalancerSourceRanges: []
  servicePort: 8085
  portName: http
  type: ClusterIP

spotinst:
  account: ""
  token: ""
  image:
    repository: spotinst/kubernetes-cluster-autoscaler
    tag: 0.6.0
    pullPolicy: IfNotPresent

cluster-autoscaler

The cluster autoscaler scales worker nodes within an AWS autoscaling group (ASG) or Spotinst Elastigroup.

TL;DR:

$ helm install stable/cluster-autoscaler --name my-release --set "autoscalingGroups[0].name=your-asg-name,autoscalingGroups[0].maxSize=10,autoscalingGroups[0].minSize=1"

Introduction

This chart bootstraps a cluster-autoscaler deployment on a Kubernetes cluster using the Helm package manager.

Prerequisites

• Kubernetes 1.8+

  older versions may work by overriding the image. Cluster-autoscaler internally simulates the scheduler and bugs between mismatched versions may be subtle.

Installing the Chart

By default, no deployment is created and nothing will autoscale.

You must provide some minimal configuration, either to specify instance groups or enable auto-discovery. It is not recommended to do both.

Either:

• set autoDiscovery.clusterName and tag your autoscaling groups appropriately (--cloud-provider=aws only) or
• set at least one ASG as an element in the autoscalingGroups array with its three values: name, minSize and maxSize.

To install the chart with the release name my-release:

Using auto-discovery of tagged instance groups

AWS

Auto-discovery finds ASGs tags as below and automatically manages them based on the min and max size specified in the ASG. cloudProvider=aws only.

1. tag the ASGs with key k8s.io/cluster-autoscaler/enabled and key kubernetes.io/cluster/<YOUR CLUSTER NAME>
2. verify the IAM Permissions
3. set autoDiscovery.clusterName=<YOUR CLUSTER NAME>

$ helm install stable/cluster-autoscaler --name my-release --set autoDiscovery.clusterName=<CLUSTER NAME>

The auto-discovery section provides more details and examples

GCE

Required parameters

• autoDiscovery.clusterName=any-name
• --cloud-provider=gce
• autoscalingGroupsnamePrefix[0].name=your-ig-prefix,autoscalingGroupsnamePrefix[0].maxSize=10,autoscalingGroupsnamePrefix[0].minSize=1

1. Either provide a yaml file setting autoscalingGroupsnamePrefix (see values.yaml) or use --set e.g.:

$ helm install stable/cluster-autoscaler \
--name my-release \
--set autoDiscovery.clusterName=<CLUSTER NAME> \
--set cloudProvider=gce \
--set autoDiscovery.clusterName=mycluster \
--set "autoscalingGroupsnamePrefix[0].name=your-ig-prefix,autoscalingGroupsnamePrefix[0].maxSize=10,autoscalingGroupsnamePrefix[0].minSize=1"

Specifying groups manually (only aws)

Without autodiscovery, specify an array of elements each containing ASG name, min size, max size. The sizes specified here will be applied to the ASG, assuming IAM permissions are correctly configured.

1. verify the IAM Permissions
2. Either provide a yaml file setting autoscalingGroups (see values.yaml) or use --set e.g.:

$ helm install stable/cluster-autoscaler --name my-release --set "autoscalingGroups[0].name=your-asg-name,autoscalingGroups[0].maxSize=10,autoscalingGroups[0].minSize=1"

Uninstalling the Chart

To uninstall my-release:

$ helm delete my-release

The command removes all the Kubernetes components associated with the chart and deletes the release.

Tip: List all releases using helm list or start clean with helm delete --purge my-release

Configuration

The following table lists the configurable parameters of the cluster-autoscaler chart and their default values.

Specify each parameter you'd like to override using a YAML file as described above in the installation section or by using the --set key=value[,key=value] argument to helm install. For example, to change the region and expander:

$ helm install stable/cluster-autoscaler --name my-release \
    --set extraArgs.expander=most-pods \
    --set awsRegion=us-west-1

IAM

The worker running the cluster autoscaler will need access to certain resources and actions:

{
    "Version": "2012-10-17",
    "Statement": [
        {
            "Effect": "Allow",
            "Action": [
                "autoscaling:DescribeAutoScalingGroups",
                "autoscaling:DescribeAutoScalingInstances",
                "autoscaling:DescribeLaunchConfigurations",
                "autoscaling:DescribeTags",
                "autoscaling:SetDesiredCapacity",
                "autoscaling:TerminateInstanceInAutoScalingGroup"
            ],
            "Resource": "*"
        }
    ]
}

• DescribeTags is required for autodiscovery.
• DescribeLaunchconfigurations is required to scale up an ASG from 0

Unfortunately AWS does not support ARNs for autoscaling groups yet so you must use "*" as the resource. More information here.

Auto-discovery

For auto-discovery of instances to work, they must be tagged with k8s.io/cluster-autoscaler/enabled and kubernetes.io/cluster/<ClusterName>

The value of the tag does not matter, only the key.

An example kops spec excerpt:

apiVersion: kops/v1alpha2
kind: Cluster
metadata:
  name: my.cluster.internal
spec:
  additionalPolicies:
    node: |
      [
        {"Effect":"Allow","Action":["autoscaling:DescribeAutoScalingGroups","autoscaling:DescribeAutoScalingInstances","autoscaling:DescribeLaunchConfigurations","autoscaling:DescribeTags","autoscaling:SetDesiredCapacity","autoscaling:TerminateInstanceInAutoScalingGroup"],"Resource":"*"}
      ]
      ...
---
apiVersion: kops/v1alpha2
kind: InstanceGroup
metadata:
  labels:
    kops.k8s.io/cluster: my.cluster.internal
  name: my-instances
spec:
  cloudLabels:
    k8s.io/cluster-autoscaler/enabled: ""
    kubernetes.io/cluster/my.cluster.internal: owned
  image: kope.io/k8s-1.8-debian-jessie-amd64-hvm-ebs-2018-01-14
  machineType: r4.large
  maxSize: 4
  minSize: 0

In this example you would need to --set autoDiscovery.clusterName=my.cluster.internal when installing.

It is not recommended to try to mix this with setting autoscalingGroups

See autoscaler AWS documentation for a more discussion of the setup

Troubleshooting

The chart will succeed even if the container arguments are incorrect. A few minutes after starting kubectl logs -l "app=aws-cluster-autoscaler" --tail=50 should loop through something like

polling_autoscaler.go:111] Poll finished
static_autoscaler.go:97] Starting main loop
utils.go:435] No pod using affinity / antiaffinity found in cluster, disabling affinity predicate for this loop
static_autoscaler.go:230] Filtering out schedulables

If not, find a pod that the deployment created and describe it, paying close attention to the arguments under Command. e.g.:

Containers:
  cluster-autoscaler:
    Command:
      ./cluster-autoscaler
      --cloud-provider=aws
# if specifying ASGs manually
      --nodes=1:10:your-scaling-group-name
# if using autodiscovery
      --node-group-auto-discovery=asg:tag=k8s.io/cluster-autoscaler/enabled,kubernetes.io/cluster/<ClusterName>
      --v=4