chore: Reduce infra cost by switching from 3-tier to 1-tier architecture

Modules/ACM/main.tf

@@ -18,13 +18,13 @@ resource "aws_acm_certificate" "cloudfront_certificate" {
   }
 }
 
-resource "aws_acm_certificate" "external_alb_certificate" {
+resource "aws_acm_certificate" "alb_certificate" {
   provider          = aws.seoul
   domain_name       = "api.${var.domain_name}"
   validation_method = "DNS"
 
   tags = {
-    Name = "dutymate-external-alb-certificate"
+    Name = "dutymate-alb-certificate"
   }
 }
 
@@ -37,8 +37,8 @@ resource "aws_route53_record" "cloudfront_route53_record" {
   ttl      = 300
 }
 
-resource "aws_route53_record" "external_alb_route53_record" {
-  for_each = { for dvo in aws_acm_certificate.external_alb_certificate.domain_validation_options : dvo.domain_name => dvo }
+resource "aws_route53_record" "alb_route53_record" {
+  for_each = { for dvo in aws_acm_certificate.alb_certificate.domain_validation_options : dvo.domain_name => dvo }
   name     = each.value.resource_record_name
   type     = each.value.resource_record_type
   zone_id  = var.route53_zone_id
@@ -52,8 +52,8 @@ resource "aws_acm_certificate_validation" "cloudfront_certificate_validation" {
   validation_record_fqdns = [for record in aws_route53_record.cloudfront_route53_record : record.fqdn]
 }
 
-resource "aws_acm_certificate_validation" "external_alb_certificate_validation" {
+resource "aws_acm_certificate_validation" "alb_certificate_validation" {
   provider                = aws.seoul
-  certificate_arn         = aws_acm_certificate.external_alb_certificate.arn
-  validation_record_fqdns = [for record in aws_route53_record.external_alb_route53_record : record.fqdn]
+  certificate_arn         = aws_acm_certificate.alb_certificate.arn
+  validation_record_fqdns = [for record in aws_route53_record.alb_route53_record : record.fqdn]
 }

Modules/ACM/outputs.tf

@@ -1,5 +1,5 @@
-output "external_alb_certificate_arn" {
-  value = aws_acm_certificate.external_alb_certificate.arn
+output "alb_certificate_arn" {
+  value = aws_acm_certificate.alb_certificate.arn
 }
 
 output "cloudfront_certificate_arn" {

Modules/ALB/main.tf

@@ -1,66 +1,27 @@
-resource "aws_alb" "external_alb" {
-  name               = "dutymate-external-alb"
+resource "aws_alb" "alb" {
+  name               = "dutymate-alb"
   subnets            = var.public_subnets
-  security_groups    = [var.sg_external_alb_id]
+  security_groups    = [var.sg_alb_id]
   load_balancer_type = "application"
   internal           = false
   enable_http2       = true
   idle_timeout       = 30
 
   tags = {
-    Name = "dutymate-external-alb"
+    Name = "dutymate-alb"
   }
 }
 
-resource "aws_alb" "internal_alb" {
-  name               = "dutymate-internal-alb"
-  subnets            = var.private_subnets
-  security_groups    = [var.sg_internal_alb_id]
-  load_balancer_type = "application"
-  internal           = true
-  enable_http2       = true
-  idle_timeout       = 30
-
-  tags = {
-    Name = "dutymate-internal-alb"
-  }
-}
-
-resource "aws_alb_target_group" "external_alb_target_group" {
-  name                 = "dutymate-external-alb-tg"
-  port                 = 80
-  protocol             = "HTTP"
-  vpc_id               = var.vpc_id
-  target_type          = "ip"
-  deregistration_delay = 5
-
-  health_check {
-    path                = var.external_alb_health_check_path
-    interval            = 30
-    timeout             = 5
-    healthy_threshold   = 3
-    unhealthy_threshold = 2
-  }
-
-  lifecycle {
-    create_before_destroy = true
-  }
-
-  tags = {
-    Name = "dutymate-external-alb-tg"
-  }
-}
-
-resource "aws_alb_target_group" "internal_alb_target_group" {
-  name                 = "dutymate-internal-alb-tg"
+resource "aws_alb_target_group" "alb_target_group" {
+  name                 = "dutymate-alb-tg"
   port                 = 8080
   protocol             = "HTTP"
   vpc_id               = var.vpc_id
-  target_type          = "ip"
+  target_type          = "instance"
   deregistration_delay = 5
 
   health_check {
-    path                = var.internal_alb_health_check_path
+    path                = var.alb_health_check_path
     interval            = 30
     timeout             = 5
     healthy_threshold   = 3
@@ -72,58 +33,43 @@ resource "aws_alb_target_group" "internal_alb_target_group" {
   }
 
   tags = {
-    Name = "dutymate-internal-alb-tg"
+    Name = "dutymate-alb-tg"
   }
 }
 
-resource "aws_alb_listener" "external_alb_http_listener" {
-  load_balancer_arn = aws_alb.external_alb.arn
+resource "aws_alb_listener" "http_listener" {
+  load_balancer_arn = aws_alb.alb.arn
   port              = 80
   protocol          = "HTTP"
 
   default_action {
     type = "redirect"
 
     redirect {
-      port        = "443"
+      port        = 443
       protocol    = "HTTPS"
       status_code = "HTTP_301"
     }
   }
 
   tags = {
-    Name = "dutymate-external-alb-http-listener"
+    Name = "dutymate-http-listener"
   }
 }
 
-resource "aws_alb_listener" "external_alb_https_listener" {
-  load_balancer_arn = aws_alb.external_alb.arn
+resource "aws_alb_listener" "https_listener" {
+  load_balancer_arn = aws_alb.alb.arn
   port              = 443
   protocol          = "HTTPS"
   ssl_policy        = "ELBSecurityPolicy-2016-08"
-  certificate_arn   = var.external_alb_certificate_arn
-
-  default_action {
-    type             = "forward"
-    target_group_arn = aws_alb_target_group.external_alb_target_group.arn
-  }
-
-  tags = {
-    Name = "dutymate-external-alb-https-listener"
-  }
-}
-
-resource "aws_alb_listener" "internal_alb_http_listener" {
-  load_balancer_arn = aws_alb.internal_alb.arn
-  port              = 8080
-  protocol          = "HTTP"
+  certificate_arn   = var.alb_certificate_arn
 
   default_action {
     type             = "forward"
-    target_group_arn = aws_alb_target_group.internal_alb_target_group.arn
+    target_group_arn = aws_alb_target_group.alb_target_group.arn
   }
 
   tags = {
-    Name = "dutymate-internal-alb-http-listener"
+    Name = "dutymate-https-listener"
   }
 }

Modules/ALB/outputs.tf

@@ -1,23 +1,15 @@
-output "external_alb_arn" {
-  value = aws_alb.external_alb.arn
+output "alb_arn" {
+  value = aws_alb.alb.arn
 }
 
-output "external_alb_dns_name" {
-  value = aws_alb.external_alb.dns_name
+output "alb_dns_name" {
+  value = aws_alb.alb.dns_name
 }
 
-output "external_alb_zone_id" {
-  value = aws_alb.external_alb.zone_id
+output "alb_zone_id" {
+  value = aws_alb.alb.zone_id
 }
 
-output "external_alb_target_group_arn" {
-  value = aws_alb_target_group.external_alb_target_group.arn
-}
-
-output "internal_alb_dns_name" {
-  value = aws_alb.internal_alb.dns_name
-}
-
-output "internal_alb_target_group_arn" {
-  value = aws_alb_target_group.internal_alb_target_group.arn
+output "alb_target_group_arn" {
+  value = aws_alb_target_group.alb_target_group.arn
 }

Modules/ALB/variables.tf

@@ -1,28 +1,16 @@
-variable "external_alb_certificate_arn" {
+variable "alb_certificate_arn" {
   type = string
 }
 
-variable "external_alb_health_check_path" {
+variable "alb_health_check_path" {
   type = string
 }
 
-variable "internal_alb_health_check_path" {
-  type = string
-}
-
-variable "sg_internal_alb_id" {
-  type = string
-}
-
-variable "private_subnets" {
-  type = list(string)
-}
-
 variable "public_subnets" {
   type = list(string)
 }
 
-variable "sg_external_alb_id" {
+variable "sg_alb_id" {
   type = string
 }
 

Modules/CloudWatch/main.tf

@@ -1,17 +1,8 @@
-resource "aws_cloudwatch_log_group" "webserver_log_group" {
-  name              = "/ecs/dutymate-webserver-service"
+resource "aws_cloudwatch_log_group" "ecs_log_group" {
+  name              = "/ecs/dutymate-service"
   retention_in_days = 7
 
   tags = {
-    Name = "dutymate-webserver-log-group"
-  }
-}
-
-resource "aws_cloudwatch_log_group" "appserver_log_group" {
-  name              = "/ecs/dutymate-appserver-service"
-  retention_in_days = 7
-
-  tags = {
-    Name = "dutymate-appserver-log-group"
+    Name = "dutymate-ecs-log-group"
   }
 }

Modules/CloudWatch/outputs.tf

@@ -1,7 +1,3 @@
-output "appserver_log_group_name" {
-  value = aws_cloudwatch_log_group.appserver_log_group.name
-}
-
-output "webserver_log_group_name" {
-  value = aws_cloudwatch_log_group.webserver_log_group.name
+output "ecs_log_group_name" {
+  value = aws_cloudwatch_log_group.ecs_log_group.name
 }

Modules/DocumentDB/main.tf

@@ -1,6 +1,6 @@
 resource "aws_docdb_subnet_group" "docdbsg" {
   name       = "dutymate-docdbsg"
-  subnet_ids = var.database_subnets
+  subnet_ids = var.public_subnets
 
   tags = {
     Name = "dutymate-docdbsg"

Modules/DocumentDB/variables.tf

@@ -1,7 +1,3 @@
-variable "database_subnets" {
-  type = list(string)
-}
-
 variable "mongodb_username" {
   type = string
 }
@@ -10,6 +6,10 @@ variable "mongodb_password" {
   type = string
 }
 
+variable "public_subnets" {
+  type = list(string)
+}
+
 variable "sg_mongodb_id" {
   type = string
 }