Expose instance type options to EKS creation form

app/assets/javascripts/create_cluster/eks_cluster/index.js

@@ -17,6 +17,7 @@ export default el => {
     sessionToken,
     externalId,
     accountId,
+    instanceTypes,
     hasCredentials,
     createRolePath,
     createClusterPath,
@@ -32,6 +33,7 @@ export default el => {
         hasCredentials: parseBoolean(hasCredentials),
         externalId,
         accountId,
+        instanceTypes: JSON.parse(instanceTypes),
         createRolePath,
         createClusterPath,
         signOutPath,

app/controllers/clusters/clusters_controller.rb

@@ -42,6 +42,7 @@ class Clusters::ClustersController < Clusters::BaseController
     if params[:provider] == 'aws'
       @aws_role = current_user.aws_role || Aws::Role.new
       @aws_role.ensure_role_external_id!
+      @instance_types = load_instance_types.to_json
 
     elsif params[:provider] == 'gcp'
       redirect_to @authorize_url if @authorize_url && !@valid_gcp_token
@@ -308,6 +309,19 @@ class Clusters::ClustersController < Clusters::BaseController
     end
   end
 
+  ##
+  # Unfortunately the EC2 API doesn't provide a list of
+  # possible instance types. There is a workaround, using
+  # the Pricing API, but instead of requiring the
+  # user to grant extra permissions for this we use the
+  # values that validate the CloudFormation template.
+  def load_instance_types
+    stack_template = File.read(Rails.root.join('vendor', 'aws', 'cloudformation', 'eks_cluster.yaml'))
+    instance_types = YAML.safe_load(stack_template).dig('Parameters', 'NodeInstanceType', 'AllowedValues')
+
+    instance_types.map { |type| Hash(name: type, value: type) }
+  end
+
   def update_applications_status
     @cluster.applications.each(&:schedule_status_update)
   end

app/views/clusters/clusters/aws/_new.html.haml

@@ -10,6 +10,7 @@
     'account-id' => Gitlab::CurrentSettings.eks_account_id,
     'external-id' => @aws_role.role_external_id,
     'role-arn' => @aws_role.role_arn,
+    'instance-types' => @instance_types,
     'kubernetes-integration-help-path' => help_page_path('user/project/clusters/index'),
     'account-and-external-ids-help-path' => help_page_path('user/project/clusters/add_remove_clusters.md', anchor: 'eks-cluster'),
     'create-role-arn-help-path' => help_page_path('user/project/clusters/add_remove_clusters.md', anchor: 'eks-cluster'),