Merge pull request #32 from HENNGE/example-ec2-managed-draining

Add example to use EC2 instance managed draining

examples/easy/ec2-managed-draining/README.md

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+# examples/easy/ec2-managed-draining
+
+In this example we'll instantiate a simple nginx webserver, running on EC2 Auto Scaling Group, with managed draining feature enabled.
+This means ECS will monitor the Auto Scaling Group and set an instance's status to draining when it's scheduled for termination.
+With draining status set, ECS will safely terminate all tasks running on the instance and create replacement tasks in other instance(s).
+
+Note: Instance profile is required for EC2 to connect to ECS Cluster. See [`modules/iam/ecs-instance-profile`](https://github.com/HENNGE/terraform-aws-ecs/tree/main/modules/iam/ecs-instance-profile).
+
+To test that it's working:
+1. Go to EC2 console
+1. Find the EC2 instance started by this example. (Search the name)
+1. Go to the IP Address, you should see nginx hello world screen
+
+## Usage
+
+To run this example you need to execute:
+
+```bash
+$ terraform init
+$ terraform plan
+$ terraform apply
+```
+
+
+<!-- BEGINNING OF PRE-COMMIT-TERRAFORM DOCS HOOK -->
+## Requirements
+
+| Name | Version |
+|------|---------|
+| <a name="requirement_terraform"></a> [terraform](#requirement\_terraform) | >= 1.0 |
+| <a name="requirement_aws"></a> [aws](#requirement\_aws) | >= 3.74.0 |
+
+## Providers
+
+| Name | Version |
+|------|---------|
+| <a name="provider_aws"></a> [aws](#provider\_aws) | >= 3.74.0 |
+
+## Modules
+
+| Name | Source | Version |
+|------|--------|---------|
+| <a name="module_asg"></a> [asg](#module\_asg) | terraform-aws-modules/autoscaling/aws | ~> 7.0 |
+| <a name="module_easy_ec2"></a> [easy\_ec2](#module\_easy\_ec2) | ../../../modules/simple/ec2 | n/a |
+| <a name="module_ec2_security_group"></a> [ec2\_security\_group](#module\_ec2\_security\_group) | terraform-aws-modules/security-group/aws | ~> 4.0 |
+| <a name="module_ecs_cluster"></a> [ecs\_cluster](#module\_ecs\_cluster) | ../../.. | n/a |
+| <a name="module_vpc"></a> [vpc](#module\_vpc) | terraform-aws-modules/vpc/aws | ~> 5.0 |
+
+## Resources
+
+| Name | Type |
+|------|------|
+| [aws_ecs_capacity_provider.asg_managed_draining](https://registry.terraform.io/providers/hashicorp/aws/latest/docs/resources/ecs_capacity_provider) | resource |
+| [aws_availability_zones.available](https://registry.terraform.io/providers/hashicorp/aws/latest/docs/data-sources/availability_zones) | data source |
+| [aws_ssm_parameter.ami_image](https://registry.terraform.io/providers/hashicorp/aws/latest/docs/data-sources/ssm_parameter) | data source |
+
+## Inputs
+
+| Name | Description | Type | Default | Required |
+|------|-------------|------|---------|:--------:|
+| <a name="input_availability_zones"></a> [availability\_zones](#input\_availability\_zones) | Override automatic detection of availability zones | `list(string)` | `[]` | no |
+| <a name="input_enable_ipv6"></a> [enable\_ipv6](#input\_enable\_ipv6) | Enable IPv6? | `bool` | `true` | no |
+| <a name="input_instance_profile_arn"></a> [instance\_profile\_arn](#input\_instance\_profile\_arn) | Instance Profile to use for EC2 to join to ECS Cluster. See `modules/iam/ecs-instance-profile` | `string` | n/a | yes |
+
+## Outputs
+
+No outputs.
+<!-- END OF PRE-COMMIT-TERRAFORM DOCS HOOK -->

examples/easy/ec2-managed-draining/main.tf

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+# Just Supporting Infrastructures
+
+data "aws_availability_zones" "available" {}
+
+data "aws_ssm_parameter" "ami_image" {
+  name = "/aws/service/ecs/optimized-ami/amazon-linux-2/recommended/image_id"
+}
+
+locals {
+  prefix = "easy-ec2"
+
+  vpc_cidr       = "10.0.0.0/16"
+  discovered_azs = data.aws_availability_zones.available.names
+  vpc_azs        = length(var.availability_zones) == 0 ? local.discovered_azs : var.availability_zones
+}
+
+module "vpc" {
+  source  = "terraform-aws-modules/vpc/aws"
+  version = "~> 5.0"
+
+  name = "${local.prefix}-vpc"
+  cidr = local.vpc_cidr
+  azs  = local.vpc_azs
+
+  public_subnets = [for i in range(length(local.vpc_azs)) : cidrsubnet(local.vpc_cidr, 8, i)]
+
+  enable_nat_gateway               = false
+  enable_dhcp_options              = true
+  dhcp_options_domain_name_servers = ["AmazonProvidedDNS"]
+
+  map_public_ip_on_launch = true
+
+  enable_ipv6                                   = var.enable_ipv6
+  public_subnet_assign_ipv6_address_on_creation = var.enable_ipv6
+  public_subnet_ipv6_prefixes                   = range(length(local.vpc_azs))
+}
+
+module "ec2_security_group" {
+  source  = "terraform-aws-modules/security-group/aws"
+  version = "~> 4.0"
+
+  name   = "${local.prefix}-ec2-sg"
+  vpc_id = module.vpc.vpc_id
+
+
+  # Ingress for HTTP
+  ingress_cidr_blocks      = ["0.0.0.0/0"]
+  ingress_ipv6_cidr_blocks = ["::/0"]
+  ingress_rules            = ["http-80-tcp"]
+
+  # Allow all egress
+  egress_cidr_blocks      = ["0.0.0.0/0"]
+  egress_ipv6_cidr_blocks = ["::/0"]
+  egress_rules            = ["all-all"]
+}
+
+module "asg" {
+  source  = "terraform-aws-modules/autoscaling/aws"
+  version = "~> 7.0"
+
+  name = "${local.prefix}-asg"
+
+  image_id            = data.aws_ssm_parameter.ami_image.value
+  instance_type       = "t2.micro"
+  security_groups     = [module.ec2_security_group.security_group_id]
+  vpc_zone_identifier = module.vpc.public_subnets
+  min_size            = 1
+  max_size            = 2
+  desired_capacity    = 1
+  health_check_type   = "EC2"
+  user_data = base64encode(templatefile("../../templates/ec2_userdata.tpl", {
+    ecs_cluster = module.ecs_cluster.name
+  }))
+  iam_instance_profile_arn = var.instance_profile_arn
+
+  tags = {
+    AmazonECSManaged = "true"
+  }
+}
+
+resource "aws_ecs_capacity_provider" "asg_managed_draining" {
+  name = "${local.prefix}-capacity-provider"
+
+  auto_scaling_group_provider {
+    auto_scaling_group_arn = module.asg.autoscaling_group_arn
+    managed_draining       = "ENABLED"
+  }
+}
+
+# This module usage starts here
+module "ecs_cluster" {
+  source = "../../.."
+
+  name = "${local.prefix}-cluster"
+
+  capacity_providers = [aws_ecs_capacity_provider.asg_managed_draining.name]
+}
+
+module "easy_ec2" {
+  source = "../../../modules/simple/ec2"
+
+  name                         = "${local.prefix}-service"
+  cluster                      = module.ecs_cluster.name
+  cpu                          = 256
+  memory                       = 512
+  desired_count                = 1
+  ignore_desired_count_changes = false
+
+  network_mode = "host"
+
+  container_definitions = templatefile("../../templates/container_definitions.tpl", {
+    name   = "${local.prefix}-cont"
+    cpu    = 256
+    memory = 512
+  })
+}

examples/easy/ec2-managed-draining/variables.tf

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+variable "instance_profile_arn" {
+  description = "Instance Profile to use for EC2 to join to ECS Cluster. See `modules/iam/ecs-instance-profile`"
+  type        = string
+}
+
+variable "availability_zones" {
+  description = "Override automatic detection of availability zones"
+  default     = []
+  type        = list(string)
+}
+
+variable "enable_ipv6" {
+  description = "Enable IPv6?"
+  default     = true
+  type        = bool
+}

examples/easy/ec2-managed-draining/versions.tf

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+terraform {
+  required_version = ">= 1.0"
+
+  required_providers {
+    aws = {
+      source  = "hashicorp/aws"
+      version = ">= 3.74.0"
+    }
+  }
+}