Allow asg to provision new instances if there are changes to userdata

terraform/platforms/aws/README.md

@@ -75,7 +75,10 @@ module "eco" {
   source = "github.com/Quentin-M/etcd-cloud-operator//terraform/platforms/aws"
 
   name = "eco-example"
-  size = "3"
+  max_size = "7"
+  min_size = "3"
+  desired_capacity = "3"
+  min_elb_capacity = "3"
 
   instance_type         = "t2.small"
   instance_disk_size    = "30"

terraform/platforms/aws/asg.tf

@@ -37,11 +37,12 @@ data "aws_ami" "coreos" {
 }
 
 resource "aws_autoscaling_group" "main" {
-  name               = "${var.name}"
+  name               = "${var.name}-${aws_launch_configuration.main.name}"
 
-  max_size         = "${var.size}"
-  min_size         = "${var.size}"
-  desired_capacity = "${var.size}"
+  max_size         = "${var.max_size}"
+  min_size         = "${var.min_size}"
+  desired_capacity = "${var.desired_capacity}"
+  min_elb_capacity = "${var.min_elb_capacity}"
 
   load_balancers            = ["${aws_elb.clients.name}"]
   health_check_grace_period = 120
@@ -50,6 +51,10 @@ resource "aws_autoscaling_group" "main" {
   vpc_zone_identifier  = ["${var.subnets_ids}"]
   launch_configuration = "${aws_launch_configuration.main.name}"
 
+  lifecycle {
+    create_before_destroy = true
+  }
+
   tags = [
     {
       key                 = "Name"
@@ -60,7 +65,6 @@ resource "aws_autoscaling_group" "main" {
 }
 
 resource "aws_launch_configuration" "main" {
-  name_prefix = "${var.name}"
 
   image_id      = "${data.aws_ami.coreos.image_id}"
   instance_type = "${var.instance_type}"

terraform/platforms/aws/variables.tf

@@ -16,8 +16,20 @@ variable "name" {
   description = "Name of the deployment"
 }
 
-variable "size" {
-  description = "Number of etcd members (must be odd)"
+variable "max_size" {
+  description = "Number of max etcd members in ASG (must be odd)"
+}
+
+variable "min_size" {
+  description = "Number of min etcd members in ASG (must be odd)"
+}
+
+variable "desired_capacity" {
+  description = "Number of desired etcd members in ASG (must be odd)"
+}
+
+variable "min_elb_capacity" {
+  description = "Number of minimum elb capacity for ASG (must be same as min_size)"
 }
 
 variable "instance_type" {