Module to get K8S join command from control plane (#2)

README.md

@@ -4,3 +4,5 @@ Hodgepodge of Terraform modules.
 * Proxmox
    * VM Clone (Create VMs from Templates (created by packer))
 
+* K8S
+    * Get Join (Get join config from Kuberenetes control plane)

modules/k8s/README.md

@@ -0,0 +1 @@
+# Kuberenetes Related Modules

modules/k8s/get-join/README.md

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+# Get Join
+
+Small module that will ssh into a k8s control plan node and run the create join command. This will return a map of info needed to run the join command as well as the full join command.
+
+Intended to be passed to cloud-init of a pre-configured worker node to auto join a cluster.

modules/k8s/get-join/get_join.sh

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+#!/bin/bash
+set -e
+
+eval "$(jq -r '@sh "k8s_host=\(.hostname) ssh_user=\(.ssh_user)"')"
+
+out=$(ssh -q ${ssh_user}@${k8s_host} <<'EOF'
+kubeadm token create --print-join-command
+EOF
+)
+
+join_command="${out##*$'\n'}"
+join_command="$(echo "$join_command"|tr -d '\n')"
+
+join_command=($join_command)
+
+
+echo $(jq -n --arg host "${join_command[2]}" --arg token "${join_command[4]}" --arg cacerthash "${join_command[6]}" '{"host":$host,"token":$token,"cacerthash":$cacerthash}')

modules/k8s/get-join/main.tf

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+
+data "external" "k8s" {
+  program = ["bash", "${path.module}/get_join.sh"]
+  query   = var.k8s_control_config
+}

modules/k8s/get-join/outputs.tf

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+output "k8s_join" {
+    description = "Map of config values needed to join a kuberentes cluster."
+    value       = data.external.k8s.result
+    senstive    = true
+}
+
+output "full_join_command" {
+    description = "Full command to join a worker node to kubernetes cluster."
+    senstive    = true
+    value       = "kubeadm join ${data.external.k8s.result.host} --token ${data.external.k8s.result.token} --discovery-token-ca-cert-hash ${data.external.k8s.result.cacerthash}"
+}

modules/k8s/get-join/variables.tf

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+variable "k8s_control_config" {
+  description = "Hostname/SSH User of K8S control plan node to get join command from. Assumes your private is deployed for `ssh_user`."
+  type        = object({
+    hostname = string
+    ssh_user = string
+  })
+}

modules/k8s/get-join/versions.tf

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+terraform {
+  required_version = ">= 1.0"
+}