data/aws: use azs for master set in manifests

data/data/aws/main.tf

@@ -15,7 +15,7 @@ module "bootstrap" {
   instance_type            = "${var.aws_bootstrap_instance_type}"
   cluster_id               = "${var.cluster_id}"
   ignition                 = "${var.ignition_bootstrap}"
-  subnet_id                = "${module.vpc.public_subnet_ids[0]}"
+  subnet_id                = "${module.vpc.az_to_private_subnet_id[var.aws_master_availability_zones[0]]}"
   target_group_arns        = "${module.vpc.aws_lb_target_group_arns}"
   target_group_arns_length = "${module.vpc.aws_lb_target_group_arns_length}"
   vpc_id                   = "${module.vpc.vpc_id}"
@@ -32,12 +32,13 @@ module "masters" {
 
   tags = "${local.tags}"
 
+  availability_zones       = "${var.aws_master_availability_zones}"
+  az_to_subnet_id          = "${module.vpc.az_to_private_subnet_id}"
   instance_count           = "${var.master_count}"
   master_sg_ids            = "${list(module.vpc.master_sg_id)}"
   root_volume_iops         = "${var.aws_master_root_volume_iops}"
   root_volume_size         = "${var.aws_master_root_volume_size}"
   root_volume_type         = "${var.aws_master_root_volume_type}"
-  subnet_ids               = "${module.vpc.private_subnet_ids}"
   target_group_arns        = "${module.vpc.aws_lb_target_group_arns}"
   target_group_arns_length = "${module.vpc.aws_lb_target_group_arns_length}"
   ec2_ami                  = "${aws_ami_copy.main.id}"

data/data/aws/master/main.tf

@@ -74,7 +74,7 @@ resource "aws_instance" "master" {
 
   iam_instance_profile = "${aws_iam_instance_profile.master.name}"
   instance_type        = "${var.instance_type}"
-  subnet_id            = "${element(var.subnet_ids, count.index)}"
+  subnet_id            = "${var.az_to_subnet_id[var.availability_zones[count.index]]}"
   user_data            = "${var.user_data_ign}"
 
   vpc_security_group_ids = ["${var.master_sg_ids}"]

data/data/aws/master/outputs.tf

@@ -1,11 +1,3 @@
-output "subnet_ids" {
-  value = "${var.subnet_ids}"
-}
-
-output "cluster_id" {
-  value = "${var.cluster_id}"
-}
-
 output "ip_addresses" {
   value = "${aws_instance.master.*.private_ip}"
 }

data/data/aws/master/variables.tf

@@ -1,3 +1,13 @@
+variable "availability_zones" {
+  type        = "list"
+  description = "List of the availability zones in which to create the masters. The length of this list must match instance_count."
+}
+
+variable "az_to_subnet_id" {
+  type        = "map"
+  description = "Map from availability zone name to the ID of the subnet in that availability zone"
+}
+
 variable "cluster_id" {
   type = "string"
 }
@@ -40,10 +50,6 @@ variable "root_volume_type" {
   description = "The type of volume for the root block device."
 }
 
-variable "subnet_ids" {
-  type = "list"
-}
-
 variable "tags" {
   type        = "map"
   default     = {}

data/data/aws/variables-aws.tf

@@ -57,3 +57,8 @@ variable "aws_region" {
   type        = "string"
   description = "The target AWS region for the cluster."
 }
+
+variable "aws_master_availability_zones" {
+  type        = "list"
+  description = "The availability zones in which to create the masters. The length of this list must match master_count."
+}

data/data/aws/vpc/outputs.tf

@@ -2,6 +2,10 @@ output "vpc_id" {
   value = "${data.aws_vpc.cluster_vpc.id}"
 }
 
+output "az_to_private_subnet_id" {
+  value = "${zipmap(local.new_subnet_azs, local.private_subnet_ids)}"
+}
+
 output "public_subnet_ids" {
   value = "${local.public_subnet_ids}"
 }

pkg/asset/cluster/tfvars.go

@@ -107,9 +107,11 @@ func (t *TerraformVariables) Generate(parents asset.Parents) error {
 		if err != nil {
 			return err
 		}
-		data, err = awstfvars.TFVars(
-			masters[0].Spec.ProviderSpec.Value.Object.(*awsprovider.AWSMachineProviderConfig),
-		)
+		masterConfigs := make([]*awsprovider.AWSMachineProviderConfig, len(masters))
+		for i, m := range masters {
+			masterConfigs[i] = m.Spec.ProviderSpec.Value.Object.(*awsprovider.AWSMachineProviderConfig)
+		}
+		data, err := awstfvars.TFVars(masterConfigs)
 		if err != nil {
 			return errors.Wrapf(err, "failed to get %s Terraform variables", platform)
 		}

pkg/tfvars/aws/aws.go

@@ -15,19 +15,27 @@ type config struct {
 	ExtraTags             map[string]string `json:"aws_extra_tags,omitempty"`
 	BootstrapInstanceType string            `json:"aws_bootstrap_instance_type,omitempty"`
 	MasterInstanceType    string            `json:"aws_master_instance_type,omitempty"`
+	AvailabilityZones     []string          `json:"aws_master_availability_zones"`
 	IOPS                  int64             `json:"aws_master_root_volume_iops"`
 	Size                  int64             `json:"aws_master_root_volume_size,omitempty"`
 	Type                  string            `json:"aws_master_root_volume_type,omitempty"`
 	Region                string            `json:"aws_region,omitempty"`
 }
 
 // TFVars generates AWS-specific Terraform variables launching the cluster.
-func TFVars(masterConfig *v1beta1.AWSMachineProviderConfig) ([]byte, error) {
+func TFVars(masterConfigs []*v1beta1.AWSMachineProviderConfig) ([]byte, error) {
+	masterConfig := masterConfigs[0]
+
 	tags := make(map[string]string, len(masterConfig.Tags))
 	for _, tag := range masterConfig.Tags {
 		tags[tag.Name] = tag.Value
 	}
 
+	availabilityZones := make([]string, len(masterConfigs))
+	for i, c := range masterConfigs {
+		availabilityZones[i] = c.Placement.AvailabilityZone
+	}
+
 	if len(masterConfig.BlockDevices) == 0 {
 		return nil, errors.New("block device slice cannot be empty")
 	}
@@ -52,9 +60,10 @@ func TFVars(masterConfig *v1beta1.AWSMachineProviderConfig) ([]byte, error) {
 	instanceClass := defaults.InstanceClass(masterConfig.Placement.Region)
 
 	cfg := &config{
-		Region:    masterConfig.Placement.Region,
-		ExtraTags: tags,
-		AMI:       *masterConfig.AMI.ID,
+		Region:                masterConfig.Placement.Region,
+		ExtraTags:             tags,
+		AMI:                   *masterConfig.AMI.ID,
+		AvailabilityZones:     availabilityZones,
 		BootstrapInstanceType: fmt.Sprintf("%s.large", instanceClass),
 		MasterInstanceType:    masterConfig.InstanceType,
 		Size:                  *rootVolume.EBS.VolumeSize,