feat: Add support for eks addons for vpc cni, kube-proxy, coredns (#54)

* feat: Add support for eks addons for vpc cni, kube-proxy, coredns

* fix: Try to fix readme formatting

Author: bmonkman

modules/eks/README.md

@@ -4,6 +4,16 @@ Create a Kubernetes cluster using EKS.
 
 ## Notes
 
+This module supports using EKS "Addons" to maintain and upgrade core resources in the cluster like the VPC CNI, kube-proxy and Core DNS.
+
+See the necessary versions for each EKS version here:
+
+[https://docs.aws.amazon.com/eks/latest/userguide/managing-vpc-cni.html](https://docs.aws.amazon.com/eks/latest/userguide/managing-vpc-cni.html)
+
+[https://docs.aws.amazon.com/eks/latest/userguide/managing-coredns.html](https://docs.aws.amazon.com/eks/latest/userguide/managing-coredns.html)
+
+[https://docs.aws.amazon.com/eks/latest/userguide/managing-kube-proxy.html](https://docs.aws.amazon.com/eks/latest/userguide/managing-kube-proxy.html)
+
 <!-- BEGINNING OF PRE-COMMIT-TERRAFORM DOCS HOOK -->
 ## Requirements
 
@@ -22,6 +32,9 @@ Create a Kubernetes cluster using EKS.
 
 | Name | Description | Type | Default | Required |
 |------|-------------|------|---------|:--------:|
+| addon\_coredns\_version | Version of CoreDNS to install. If empty you will need to upgrade CoreDNS yourself during a cluster version upgrade | `string` | `""` | no |
+| addon\_kube\_proxy\_version | Version of kube proxy to install. If empty you will need to upgrade kube proxy yourself during a cluster version upgrade | `string` | `""` | no |
+| addon\_vpc\_cni\_version | Version of the VPC CNI to install. If empty you will need to upgrade the CNI yourself during a cluster version upgrade | `string` | `""` | no |
 | cluster\_name | Name to be given to the EKS cluster | `any` | n/a | yes |
 | cluster\_version | EKS cluster version number to use. Incrementing this will start a cluster upgrade | `any` | n/a | yes |
 | eks\_node\_groups | Map of maps of EKS node group config where keys are node group names | <pre>map(object({<br>    instance_types     = list(string)<br>    asg_min_size       = string<br>    asg_max_size       = string<br>    use_spot_instances = bool<br>    ami_type           = string<br>  }))</pre> | n/a | yes |

modules/eks/main.tf

@@ -72,3 +72,30 @@ module "eks" {
     environment = var.environment
   }
 }
+
+resource "aws_eks_addon" "vpc_cni" {
+  count = var.addon_vpc_cni_version == "" ? 0 : 1
+
+  cluster_name      = var.cluster_name
+  addon_name        = "vpc-cni"
+  resolve_conflicts = "OVERWRITE"
+  addon_version     = var.addon_vpc_cni_version
+}
+
+resource "aws_eks_addon" "kube_proxy" {
+  count = var.addon_kube_proxy_version == "" ? 0 : 1
+
+  cluster_name      = var.cluster_name
+  addon_name        = "kube-proxy"
+  resolve_conflicts = "OVERWRITE"
+  addon_version     = var.addon_kube_proxy_version
+}
+
+resource "aws_eks_addon" "coredns" {
+  count = var.addon_coredns_version == "" ? 0 : 1
+
+  cluster_name      = var.cluster_name
+  addon_name        = "coredns"
+  resolve_conflicts = "OVERWRITE"
+  addon_version     = var.addon_coredns_version
+}

modules/eks/variables.tf

@@ -46,3 +46,21 @@ variable "iam_role_mapping" {
   }))
   description = "List of mappings of AWS Roles to Kubernetes Groups"
 }
+
+variable "addon_vpc_cni_version" {
+  description = "Version of the VPC CNI to install. If empty you will need to upgrade the CNI yourself during a cluster version upgrade"
+  type        = string
+  default     = ""
+}
+
+variable "addon_kube_proxy_version" {
+  description = "Version of kube proxy to install. If empty you will need to upgrade kube proxy yourself during a cluster version upgrade"
+  type        = string
+  default     = ""
+}
+
+variable "addon_coredns_version" {
+  description = "Version of CoreDNS to install. If empty you will need to upgrade CoreDNS yourself during a cluster version upgrade"
+  type        = string
+  default     = ""
+}