From ec2f1fdef596e1d46746acf3d404b8bd14cc7984 Mon Sep 17 00:00:00 2001
From: Jongwoo Han <jongwooo.han@gmail.com>
Date: Mon, 29 Dec 2025 09:38:33 +0900
Subject: [PATCH 1/4] chore: Add memoryReservation to ECS task definition

---
 Modules/AWS/ECS/main.tf | 11 ++++++-----
 1 file changed, 6 insertions(+), 5 deletions(-)

diff --git a/Modules/AWS/ECS/main.tf b/Modules/AWS/ECS/main.tf
index 9edc552..230ba81 100644
--- a/Modules/AWS/ECS/main.tf
+++ b/Modules/AWS/ECS/main.tf
@@ -19,11 +19,12 @@ resource "aws_ecs_task_definition" "ecs_task_definition" {
 
   container_definitions = jsonencode([
     {
-      name      = "dutymate-container",
-      image     = "${var.ecr_repository_url}:latest",
-      memory    = 768,
-      cpu       = 512,
-      essential = true,
+      name              = "dutymate-container",
+      image             = "${var.ecr_repository_url}:latest",
+      cpu               = 512,
+      memoryReservation = 512,
+      memory            = 768,
+      essential         = true,
       portMappings = [{
         containerPort = 8080,
         hostPort      = 8080,

From b5cc99da54c054970e56c715090ce9c65d11e22c Mon Sep 17 00:00:00 2001
From: Jongwoo Han <jongwooo.han@gmail.com>
Date: Mon, 29 Dec 2025 09:40:17 +0900
Subject: [PATCH 2/4] chore: Enforce one-task-per-instance placement for ECS
 service

---
 Modules/AWS/ECS/main.tf | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/Modules/AWS/ECS/main.tf b/Modules/AWS/ECS/main.tf
index 230ba81..8d4d983 100644
--- a/Modules/AWS/ECS/main.tf
+++ b/Modules/AWS/ECS/main.tf
@@ -60,6 +60,16 @@ resource "aws_ecs_service" "ecs_service" {
   deployment_minimum_healthy_percent = 50
   deployment_maximum_percent         = 100
 
+  capacity_provider_strategy {
+    capacity_provider = aws_ecs_capacity_provider.capacity_provider.name
+    base              = 2
+    weight            = 1
+  }
+
+  placement_constraints {
+    type = "distinctInstance"
+  }
+
   load_balancer {
     target_group_arn = var.alb_target_group_arn
     container_port   = 8080

From c94ef8f89f6a3221bb817ec6a21427a37fd68164 Mon Sep 17 00:00:00 2001
From: Jongwoo Han <jongwooo.han@gmail.com>
Date: Mon, 29 Dec 2025 09:40:35 +0900
Subject: [PATCH 3/4] chore: Tune ECS capacity provider target capacity

---
 Modules/AWS/ECS/main.tf | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/Modules/AWS/ECS/main.tf b/Modules/AWS/ECS/main.tf
index 8d4d983..239464f 100644
--- a/Modules/AWS/ECS/main.tf
+++ b/Modules/AWS/ECS/main.tf
@@ -154,10 +154,10 @@ resource "aws_ecs_capacity_provider" "capacity_provider" {
     managed_termination_protection = "ENABLED"
 
     managed_scaling {
+      status                    = "ENABLED"
+      target_capacity           = 90
       maximum_scaling_step_size = 5
       minimum_scaling_step_size = 1
-      status                    = "ENABLED"
-      target_capacity           = 100
     }
   }
 

From eb261595c53278eccea6f5ab295990d495a49bac Mon Sep 17 00:00:00 2001
From: Jongwoo Han <jongwooo.han@gmail.com>
Date: Mon, 29 Dec 2025 09:41:37 +0900
Subject: [PATCH 4/4] chore: Set deregistration delay to 30

---
 Modules/AWS/ALB/main.tf | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/Modules/AWS/ALB/main.tf b/Modules/AWS/ALB/main.tf
index 9c8ca3e..8cefe0f 100644
--- a/Modules/AWS/ALB/main.tf
+++ b/Modules/AWS/ALB/main.tf
@@ -18,7 +18,7 @@ resource "aws_alb_target_group" "alb_target_group" {
   protocol             = "HTTP"
   vpc_id               = var.vpc_id
   target_type          = "instance"
-  deregistration_delay = 5
+  deregistration_delay = 30
 
   health_check {
     path                = var.alb_health_check_path