Hi, I have a terraform script (below) which causes instances to consistently stop before their status checks are complete. The log I get in the Scaling group activity group states for each instance:

'Launching a new EC2 instance: i-04d7eb490406c33dc. Status Reason: Instance became unhealthy while waiting for instance to be in InService state. Termination Reason: Client.InstanceInitiatedShutdown: Instance initiated shutdown

At 2024-01-12T11:41:03Z an instance was launched in response to an unhealthy instance needing to be replaced.'

Below is the script - when I spin up the AMI via the console it works fine:

provider "aws" { region = "eu-west-1" }

Create a VPC

resource "aws_vpc" "my_vpc" { cidr_block = "10.0.0.0/16" enable_dns_support = true enable_dns_hostnames = true }

Create Internet Gateway

resource "aws_internet_gateway" "gw" { vpc_id = aws_vpc.my_vpc.id }

Create four subnets

resource "aws_subnet" "public_subnet_1" { vpc_id = aws_vpc.my_vpc.id cidr_block = "10.0.1.0/24" availability_zone = "eu-west-1a" map_public_ip_on_launch = true }

resource "aws_subnet" "public_subnet_2" { vpc_id = aws_vpc.my_vpc.id cidr_block = "10.0.2.0/24" availability_zone = "eu-west-1b" map_public_ip_on_launch = true }

resource "aws_subnet" "private_subnet_1" { vpc_id = aws_vpc.my_vpc.id cidr_block = "10.0.3.0/24" availability_zone = "eu-west-1a" }

resource "aws_subnet" "private_subnet_2" { vpc_id = aws_vpc.my_vpc.id cidr_block = "10.0.4.0/24" availability_zone = "eu-west-1b" }

Create Route Table for Public Subnets

resource "aws_route_table" "public_rt" { vpc_id = aws_vpc.my_vpc.id route { cidr_block = "0.0.0.0/0" gateway_id = aws_internet_gateway.gw.id } }

Associate Route Table with Public Subnets

resource "aws_route_table_association" "public_rt_assoc1" { subnet_id = aws_subnet.public_subnet_1.id route_table_id = aws_route_table.public_rt.id }

resource "aws_route_table_association" "public_rt_assoc2" { subnet_id = aws_subnet.public_subnet_2.id route_table_id = aws_route_table.public_rt.id }

Create a Security Group for the EC2 instances

resource "aws_security_group" "ec2_sg" { vpc_id = aws_vpc.my_vpc.id egress { from_port = 0 to_port = 0 protocol = "-1" cidr_blocks = ["0.0.0.0/0"] } ingress { from_port = 22 to_port = 22 protocol = "tcp" cidr_blocks = ["0.0.0.0/0"] } ingress { from_port = 80 to_port = 80 protocol = "tcp" cidr_blocks = ["0.0.0.0/0"] } }

Create a Load Balancer

resource "aws_lb" "my_lb" { name = "my-lb" internal = false load_balancer_type = "application" security_groups = [aws_security_group.ec2_sg.id] subnets = [aws_subnet.public_subnet_1.id, aws_subnet.public_subnet_2.id] enable_deletion_protection = false }

resource "aws_lb_listener" "front_end" { load_balancer_arn = aws_lb.my_lb.arn port = "80" protocol = "HTTP" default_action { type = "forward" target_group_arn = aws_lb_target_group.my_tg.arn } }

resource "aws_lb_target_group" "my_tg" { name = "my-tg" port = 80 protocol = "HTTP" vpc_id = aws_vpc.my_vpc.id health_check { enabled = true interval = 30 path = "/" port = "traffic-port" protocol = "HTTP" healthy_threshold = 3 unhealthy_threshold = 3 timeout = 5 matcher = "200-299" } }

Define Launch Template

resource "aws_launch_template" "my_lt" { name_prefix = "lt-" image_id = "ami-05d4867ed58f446d9" instance_type = "t2.micro"

block_device_mappings { device_name = "/dev/sda1" ebs { volume_size = 20 volume_type = "gp3" throughput = 125 delete_on_termination = true encrypted = false } }

network_interfaces { associate_public_ip_address = true security_groups = [aws_security_group.ec2_sg.id] } }

Create Auto Scaling Group

resource "aws_autoscaling_group" "my_asg" { vpc_zone_identifier = [aws_subnet.public_subnet_1.id, aws_subnet.public_subnet_2.id] max_size = 8 min_size = 2 desired_capacity = 2 launch_template { id = aws_launch_template.my_lt.id version = "$Latest" } target_group_arns = [aws_lb_target_group.my_tg.arn]

tag { key = "Name" value = "my-instance" propagate_at_launch = true }

health_check_type = "ELB" health_check_grace_period = 900 force_delete = true }

Auto Scaling Policy for scale up

resource "aws_autoscaling_policy" "scale_up" { name = "scale-up-on-high-cpu" scaling_adjustment = 1 adjustment_type = "ChangeInCapacity" cooldown = 300 autoscaling_group_name = aws_autoscaling_group.my_asg.name }

CloudWatch Metric Alarm for high CPU

resource "aws_cloudwatch_metric_alarm" "high_cpu_alarm" { alarm_name = "high-cpu-usage" comparison_operator = "GreaterThanThreshold" evaluation_periods = 2 metric_name = "CPUUtilization" namespace = "AWS/EC2" period = 300 statistic = "Average" threshold = 65 alarm_description = "This alarm monitors EC2 CPU usage and triggers scaling up." dimensions = { AutoScalingGroupName = aws_autoscaling_group.my_asg.name } alarm_actions = [aws_autoscaling_policy.scale_up.arn] }