Develop

environments/dev/alb-asg/main.tf

@@ -127,6 +127,8 @@ module "asg" {
   environment                     = var.environment
   cost_center                     = var.cost_center
   application                     = var.application
+  instance_warmup_time            = var.instance_warmup_time
+  target_value                    = var.target_value
   alb_target_group_arn            = module.alb.alb_target_group_arn
   iam_role                        = module.iam-policy.iam_role
   security_group_ids              = module.instance-sg.security_group_ids

environments/dev/alb-asg/variables.tf

@@ -362,3 +362,13 @@ variable "alb_create_egress_sg" {
   type        = bool
   description = "Enable or disable CIDR block egress rules."
 }
+
+variable "instance_warmup_time" {
+  description = "Time required to warm up a new instance"
+  type        = number
+}
+
+variable "target_value" {
+  description = "Threshold value of asg to start scaling"
+  type        = number
+}

modules/asg/main.tf

@@ -58,6 +58,22 @@ resource "aws_autoscaling_group" "application_asg" {
 
 }
 
+resource "aws_autoscaling_policy" "cpu_scaling_policy" {
+  name                   = "${var.environment}-${var.application}-cpu-scaling-policy"
+  policy_type            = "TargetTrackingScaling"
+  estimated_instance_warmup = var.instance_warmup_time
+  autoscaling_group_name = aws_autoscaling_group.application_asg.name
+
+  target_tracking_configuration {
+    predefined_metric_specification {
+      predefined_metric_type = "ASGAverageCPUUtilization"
+    }
+
+    target_value = var.target_value
+  }
+}
+
+
 resource "aws_autoscaling_attachment" "application_asg_attachment" {
   autoscaling_group_name = aws_autoscaling_group.application_asg.name
   lb_target_group_arn    = var.alb_target_group_arn

modules/asg/variables.tf

@@ -94,3 +94,12 @@ variable "alb_target_group_arn" {
   type        = string
 }
 
+variable "instance_warmup_time" {
+  description = "Time required to warm up a new instance"
+  type        = number
+}
+
+variable "target_value" {
+  description = "Threshold value of asg to start scaling"
+  type        = number
+}

vars/dev/alb-asg.tfvars

@@ -29,8 +29,8 @@ alb_egress_sg_protocol         = ["-1"]
 alb_create_egress_sg           = false
 
 # instance sg
-ingress_cidr_from_port         = [80]
-ingress_cidr_to_port           = [80]
+ingress_cidr_from_port         = [22]
+ingress_cidr_to_port           = [22]
 ingress_cidr_protocol          = ["tcp"]
 ingress_cidr_block             = ["0.0.0.0/0"]
 create_ingress_cidr            = true
@@ -86,10 +86,12 @@ user_data                        = <<-EOF
                                    EOF
 
 #autoscaling_group
-max_size                         = 1
+max_size                         = 2
 min_size                         = 1
 desired_capacity                 = 1
 propagate_at_launch              = true
+instance_warmup_time             = 30
+target_value                     = 50
 
 #tags
 owner                            = "techiescamp"