AWS K3s Terraform Module

Terraform module that creates a HA K3s Cluster in AWS cloud and deploys a set of core addons.

Prerequisites

Key Features

• Embedded etcd cluster with autoheal capabilities.
• Cluster Disaster Recovery procedures.

Principal Diagram

Structure

module
├── files               - cloud-config user-data
├── infra.tf            - masters and workers ASG definition
├── init.tf             - Terraform requirements
├── locals.tf           - local values and helpers
├── nlb.tf              - Load-balancer definition
├── outputs.tf          - Module outputs
├── security_groups.tf  - AWS SG list
├── variables.tf        - Terraform variables
└── iam.tf              - IAM policies

Requirements

Name	Version
terraform	~> 0.13.4
aws	~> 3.0
helm	~> 1.0
kubernetes	~> 1.13.3
null	~> 2.1
random	~> 2.2
template	~> 2.1

Providers

Name	Version
aws	~> 3.0
local	n/a
null	~> 2.1
random	~> 2.2
template	~> 2.1

Inputs

Name	Description	Type	Default	Required
cluster_name	Cluster name	string	n/a	yes
domain	DNS zone record to assign to NLB	string	n/a	yes
extra_api_args	A list of additional arguments for kubeapi	map	{}	no
k3s_version	Version of k3s engine: https://github.com/rancher/k3s/releases	string	n/a	yes
key_name	The key name to use for the instances	string	n/a	yes
kubeconfig_filename	Name of file to save kubeconfig local.	string	"./kubeconfig"	no
master_additional_tags	A list of additional tags for master nodes instances	map(string)	{}	no
master_iam_instance_profile	IAM instance profile to be attached to master instances	string	""	no
master_instance_type	Instance type for master nodes.	string	"t3.medium"	no
master_node_count	Number of nodes. Should be even: 1,3,5,7..	number	3	no
master_node_labels	A list of additional labels to be added to the k3s master nodes	list	[]	no
master_node_taints	A list of additional taints to be added to the k3s master nodes	list	[]	no
master_root_volume_size	Root block device size on nodes	number	50	no
master_security_group_ids	A list of additional security groups to be attached to master nodes	list(string)	[]	no
public_subnets	List of public subnets to run ingress LB	list	n/a	yes
region	AWS Region	string	n/a	yes
s3_bucket	Kubeconfig Storage bucket	any	n/a	yes
worker_iam_instance_profile	IAM instance profile to be attached to worker instances	string	""	no
worker_node_groups	A list of worker groups configs	any	[]	no

Outputs

Name	Description
k8s_nlb_dns_name	n/a
kubeconfig	n/a
kubeconfig_s3_url	n/a

Worker node groups configuration options

worker_node_groups is a list of maps, each element of which describes one k3s worker nodes group and must correspond to the options described below.

Name	Description	Type	Default	Required
name	Worker node group name	string	n/a	yes
max_size	Maximum number of node in nodes group	number	n/a	yes
min_size	Minimum number of node in nodes group	number	n/a	yes
desired_capacity	Desired number of nodes in nodes group	number	min_size	no
instance_type	Instance type wor master nodes.	string	t3.medium	no
root_volume_size	Root block device size on nodes	number	100	no
node_labels	A list of additional labels to be added to the k3s nodes	list(string)	[]	no
node_taints	A list of additional taints to be added to the k3s nodes	list(string)	[]	no
additional_security_group_ids	A list of additional security groups to be attached to node group instances	list(string)	[]	no
tags	A list of additional tags to be attached to node group instances	map(string)	{}	no

Example of full and minimal worker group configs:

module "k3s" {
  source           = "git::ssh://git@github.com/shalb/terraform-aws-k3s.git"
  ... skipped for the brevity
  worker_node_groups = [
  # Full node group config.
    {
      name                          = "node_pool1"
      min_size                      = 2
      max_size                      = 5
      desired_capacity              = 2
      root_volume_size              = 50
      instance_type                 = "t3.medium"
      additional_security_group_ids = [
        "SG-EXAMPLE1",
        "SG-EXAMPLE2"
      ]
      tags = {
        tag-key1 = "value"
        tag-key2 = "value2"
      }
      node_labels = [
        "label_key=some_value",
        "foo=bar"
      ]
      node_taints = [
        "key=value:NoExecute"
        "key2=value2:NoExecute"
      ]
    },
    # Minimal node group config.
    {
      name        = "node_pool2"
      min_size    = 1
      max_size    = 1
    }
  ]

}