terraform-aws-eks-cluster-autoscaler

Terraform module for deploying Kubernetes Cluster Autoscaler inside a pre-existing EKS cluster. Cluster Autoscaler is a tool that automatically adjusts the size of the Kubernetes cluster when one of the following conditions is true:

• There are pods that failed to run in the cluster due to insufficient resources.
• There are nodes in the cluster that have been underutilized for an extended period of time and their pods can be placed on other existing nodes.

Prerequisites

Before deploying the Cluster Autoscaler, you must meet the following prerequisites:

• Have an existing Kubernetes cluster.
• Node groups with Auto Scaling groups tags – The Cluster Autoscaler requires the following tags on your Auto Scaling groups so that they can be auto-discovered. For more information, see Tagging your Amazon EC2 resources in the Amazon EC2 User Guide for Linux Instances.

Key	Value
k8s.io/cluster-autoscaler/<cluster-name>	owned
k8s.io/cluster-autoscaler/enabled	TRUE

Usage

module "cluster_autoscaler" {
  source = "git::https://github.com/DNXLabs/terraform-aws-eks-cluster-autoscaler.git"

  enabled = true

  cluster_name                     = module.eks_cluster.cluster_id
  cluster_identity_oidc_issuer     = module.eks_cluster.cluster_oidc_issuer_url
  cluster_identity_oidc_issuer_arn = module.eks_cluster.oidc_provider_arn
  aws_region                       = data.aws_region.current.name
}

Auto-Discovery Setup

Auto-Discovery Setup is the preferred method to configure Cluster Autoscaler.

To enable this, provide the --node-group-auto-discovery flag as an argument whose value is a list of tag keys that should be looked for. For example, --node-group-auto-discovery=asg:tag=k8s.io/cluster-autoscaler/enabled,k8s.io/cluster-autoscaler/ will find the ASGs where those tag keys exist. It does not matter what value the tags have.

Requirements

Name	Version
terraform	>= 0.13
aws	>= 3.13
helm	>= 1.0
kubernetes	>= 1.10.0

Providers

Name	Version
aws	>= 3.13
helm	>= 1.0
kubernetes	>= 1.10.0

Inputs

Name	Description	Type	Default	Required
aws_region	AWS region where secrets are stored.	string	n/a	yes
cluster_identity_oidc_issuer	The OIDC Identity issuer for the cluster.	string	n/a	yes
cluster_identity_oidc_issuer_arn	The OIDC Identity issuer ARN for the cluster that can be used to associate IAM roles with a service account.	string	n/a	yes
cluster_name	The name of the cluster	string	n/a	yes
create_namespace	Whether to create Kubernetes namespace with name defined by namespace.	bool	true	no
enabled	Variable indicating whether deployment is enabled.	bool	true	no
fullname_override	Helm fullnameOverride	string	"aws-cluster-autoscaler"	no
helm_chart_name	Cluster Autoscaler Helm chart name to be installed	string	"cluster-autoscaler"	no
helm_chart_release_name	Helm release name	string	"cluster-autoscaler"	no
helm_chart_repo	Cluster Autoscaler repository name.	string	"https://kubernetes.github.io/autoscaler"	no
helm_chart_version	Cluster Autoscaler Helm chart version.	string	"9.9.2"	no
mod_dependency	Dependence variable binds all AWS resources allocated by this module, dependent modules reference this variable.	any	null	no
namespace	Kubernetes namespace to deploy Cluster Autoscaler Helm chart.	string	"kube-system"	no
service_account_name	Cluster Autoscaler service account name	string	"cluster-autoscaler"	no
settings	Additional settings which will be passed to the Helm chart values.	map	{}	no

Outputs

No output.

Authors

Module managed by DNX Solutions.

License

Apache 2 Licensed. See LICENSE for full details.