### Example Autoscaling Module Configuration (v4.x)

Source: https://github.com/terraform-aws-modules/terraform-aws-autoscaling/blob/master/docs/UPGRADE-5.0.md

An example of how the autoscaling module was configured in version 4.x. This serves as a baseline before upgrading.

```hcl
module "example" {
  source  = "terraform-aws-modules/autoscaling/aws"
  version = "~> 4.x"

  # <your configs>
}
```

--------------------------------

### Terraform Initialization and Application

Source: https://github.com/terraform-aws-modules/terraform-aws-autoscaling/blob/master/examples/complete/README.md

Commands to initialize, plan, and apply Terraform configurations for the Auto Scaling Group examples.

```bash
$ terraform init
$ terraform plan
$ terraform apply
```

--------------------------------

### Example Autoscaling Module Configuration (v5.x with new feature)

Source: https://github.com/terraform-aws-modules/terraform-aws-autoscaling/blob/master/docs/UPGRADE-5.0.md

An example of the autoscaling module configured for version 5.x, including the new `ignore_desired_capacity_changes` parameter.

```hcl
module "example" {
  source  = "terraform-aws-modules/autoscaling/aws"
  version = "~> 5.x"

  # <your configs>

  ignore_desired_capacity_changes = true
}
```

--------------------------------

### One-Time Schedule Example

Source: https://github.com/terraform-aws-modules/terraform-aws-autoscaling/blob/master/_autodocs/api-reference/schedules.md

Configures a one-time scheduled action to adjust desired capacity at a specific start time. Requires 'start_time' in RFC3339 UTC format.

```hcl
schedules = {
  scale_up_morning = {
    desired_capacity = 5
    start_time       = "2024-06-01T08:00:00Z"
  }
}
```

--------------------------------

### Classic Load Balancer Attachment Example

Source: https://github.com/terraform-aws-modules/terraform-aws-autoscaling/blob/master/_autodocs/api-reference/traffic-source-attachment.md

Demonstrates attaching a classic load balancer to an Auto Scaling group. This example includes the necessary ELB resource and the module configuration for the Auto Scaling group.

```hcl
resource "aws_elb" "classic" {
  name = "classic-lb"
  # ... ELB configuration ...
}

module "asg" {
  source = "terraform-aws-modules/autoscaling/aws"

  name = "classic-elb-asg"
  # ... other configuration ...
  
  traffic_source_attachments = {
    elb = {
      traffic_source_identifier = aws_elb.classic.name
      traffic_source_type       = "elb"
    }
  }
}
```

--------------------------------

### Configure Secondary Network Interfaces

Source: https://github.com/terraform-aws-modules/terraform-aws-autoscaling/blob/master/_autodocs/api-reference/launch-template.md

Attach additional network interfaces to your instance at launch time. This is useful for complex networking setups.

```hcl
dynamic "secondary_interfaces" {
  for_each = var.secondary_interfaces != null ? var.secondary_interfaces : []
}
```

--------------------------------

### Step Scaling Policy Example

Source: https://github.com/terraform-aws-modules/terraform-aws-autoscaling/blob/master/_autodocs/api-reference/scaling-policies.md

Configures a Step Scaling policy with multiple step adjustments based on metric intervals. The `estimated_instance_warmup` parameter is important for accurate scaling.

```hcl
module "asg" {
  source = "terraform-aws-modules/autoscaling/aws"

  name = "step-scaling-asg"
  # ... other configuration ...
  
  scaling_policies = {
    scale_up_steps = {
      policy_type             = "StepScaling"
      adjustment_type         = "ChangeInCapacity"
      metric_aggregation_type = "Average"
      estimated_instance_warmup = 300
      
      step_adjustment = [
        {
          metric_interval_lower_bound = 0
          metric_interval_upper_bound = 15
          scaling_adjustment          = 1
        },
        {
          metric_interval_lower_bound = 15
          metric_interval_upper_bound = 30
          scaling_adjustment          = 2
        },
        {
          metric_interval_lower_bound = 30
          scaling_adjustment          = 3
        }
      ]
    }
  }
}
```

--------------------------------

### Basic Launch Template Configuration

Source: https://github.com/terraform-aws-modules/terraform-aws-autoscaling/blob/master/_autodocs/api-reference/launch-template.md

Example of creating a basic launch template for an Auto Scaling Group, specifying essential parameters like AMI, instance type, and network configuration.

```HCL
module "asg" {
  source = "terraform-aws-modules/autoscaling/aws"

  name = "my-asg"
  
  # Launch template
  create_launch_template = true
  launch_template_name   = "my-launch-template"
  image_id               = "ami-0c55b159cbfafe1f0"
  instance_type          = "t3.micro"
  
  # Network
  vpc_zone_identifier = ["subnet-123", "subnet-456"]
  security_groups     = ["sg-123456"]
  
  # EBS
  enable_monitoring = true
  ebs_optimized     = false
  
  # Capacity
  min_size         = 1
  max_size         = 3
  desired_capacity = 2
}
```

--------------------------------

### Single ALB Target Group Attachment Example

Source: https://github.com/terraform-aws-modules/terraform-aws-autoscaling/blob/master/_autodocs/api-reference/traffic-source-attachment.md

Demonstrates attaching a single ALB target group to an Auto Scaling group. This example includes the necessary ALB and target group resources along with the module configuration for the Auto Scaling group.

```hcl
resource "aws_lb" "app" {
  name = "app-alb"
  # ... ALB configuration ...
}

resource "aws_lb_target_group" "app" {
  name        = "app-targets"
  port        = 80
  protocol    = "HTTP"
  vpc_id      = aws_vpc.main.id
  target_type = "instance"
  
  health_check {
    healthy_threshold   = 2
    unhealthy_threshold = 2
    timeout             = 5
    interval            = 30
    path                = "/"
  }
}

module "asg" {
  source = "terraform-aws-modules/autoscaling/aws"

  name = "alb-asg"
  # ... other configuration ...
  
  traffic_source_attachments = {
    alb = {
      traffic_source_identifier = aws_lb_target_group.app.arn
      traffic_source_type       = "elbv2"
    }
  }
}
```

--------------------------------

### Launch Template with User Data and Key Pair

Source: https://github.com/terraform-aws-modules/terraform-aws-autoscaling/blob/master/_autodocs/api-reference/launch-template.md

Example demonstrating how to include user data and a key pair when creating a launch template for an Auto Scaling Group. User data is base64-encoded and can execute scripts on instance launch.

```HCL
module "asg" {
  source = "terraform-aws-modules/autoscaling/aws"

  name = "web-asg"
  image_id   = "ami-0c55b159cbfafe1f0"
  instance_type = "t3.small"
  key_name   = "my-keypair"
  
  user_data = base64encode(file("${path.module}/user_data.sh"))
  
  vpc_zone_identifier = ["subnet-123", "subnet-456"]
  min_size = 2
  max_size = 5
}
```

--------------------------------

### Autoscaling Module Configuration Before v5.x

Source: https://github.com/terraform-aws-modules/terraform-aws-autoscaling/blob/master/docs/UPGRADE-5.0.md

This example shows the configuration of the autoscaling module using version 4.x, including settings for both the autoscaling group and the launch configuration.

```hcl
module "asg" {
  source  = "terraform-aws-modules/autoscaling/aws"
  version = "~> 4.0"

  # Autoscaling group
  name = "example-asg"

  min_size            = 0
  max_size            = 1
  desired_capacity    = 1
  health_check_type   = "EC2"
  vpc_zone_identifier = ["subnet-1235678", "subnet-87654321"]

  # Launch template
  lt_name                = "example-asg"
  description            = "Launch template example"
  update_default_version = true
  use_lt                 = true
  create_lt              = true

  image_id      = "ami-ebd02392"
  instance_type = "t3.micro"

  tags_as_map = {
    extra_tag1 = "extra_value1"
    extra_tag2 = "extra_value2"
  }
}
```

--------------------------------

### Complete Autoscaling Group with ALB and Health Checks

Source: https://github.com/terraform-aws-modules/terraform-aws-autoscaling/blob/master/_autodocs/api-reference/traffic-source-attachment.md

A comprehensive example of an autoscaling group configured with an ALB, target group, health checks, and scaling policies. This snippet demonstrates a full setup for production environments.

```hcl
module "asg" {
  source = "terraform-aws-modules/autoscaling/aws"

  name = "complete-alb-asg"
  
  # Capacity
  min_size         = 2
  max_size         = 10
  desired_capacity = 3
  
  # Network
  vpc_zone_identifier = ["subnet-123", "subnet-456"]
  
  # Launch template
  image_id      = "ami-0c55b159cbfafe1f0"
  instance_type = "t3.micro"
  
  # Health checks
  health_check_type         = "ELB"
  health_check_grace_period = 300
  
  # Traffic source attachment
  traffic_source_attachments = {
    alb = {
      traffic_source_identifier = aws_lb_target_group.app.arn
      traffic_source_type       = "elbv2"
    }
  }
  
  # Scaling policies
  scaling_policies = {
    target_cpu = {
      policy_type = "TargetTrackingScaling"
      target_tracking_configuration = {
        target_value = 70.0
        predefined_metric_specification = {
          predefined_metric_type = "ALBRequestCountPerTarget"
          resource_label         = "${aws_lb.app.arn_suffix}/${aws_lb_target_group.app.arn_suffix}"
        }
      }
    }
  }
  
  tags = {
    Environment = "production"
  }
}

# ALB and target group
resource "aws_lb" "app" {
  name            = "app-alb"
  internal        = false
  load_balancer_type = "application"
  security_groups = [aws_security_group.alb.id]
  subnets         = ["subnet-123", "subnet-456"]
}

resource "aws_lb_target_group" "app" {
  name        = "app-tg"
  port        = 80
  protocol    = "HTTP"
  vpc_id      = aws_vpc.main.id
  target_type = "instance"
  
  health_check {
    healthy_threshold   = 2
    unhealthy_threshold = 2
    timeout             = 5
    interval            = 30
    path                = "/"
    matcher             = "200"
  }
  
  stickiness {
    type            = "lb_cookie"
    enabled         = true
    cookie_duration = 86400
  }
}

resource "aws_lb_listener" "http" {
  load_balancer_arn = aws_lb.app.arn
  port              = 80
  protocol          = "HTTP"
  
  default_action {
    type             = "forward"
    target_group_arn = aws_lb_target_group.app.arn
  }
}
```

--------------------------------

### Target Tracking Scaling Policy (CPU) Example

Source: https://github.com/terraform-aws-modules/terraform-aws-autoscaling/blob/master/_autodocs/api-reference/scaling-policies.md

Sets up a Target Tracking Scaling policy to maintain average CPU utilization at a target value. `disable_scale_in` can be set to `true` to prevent scaling in.

```hcl
module "asg" {
  source = "terraform-aws-modules/autoscaling/aws"

  name = "target-tracking-asg"
  # ... other configuration ...
  
  scaling_policies = {
    target_cpu = {
      policy_type = "TargetTrackingScaling"
      
      target_tracking_configuration = {
        target_value = 50.0
        disable_scale_in = false
        
        predefined_metric_specification = {
          predefined_metric_type = "ASGAverageCPUUtilization"
        }
      }
    }
  }
}
```

--------------------------------

### Define Scaling Policies

Source: https://github.com/terraform-aws-modules/terraform-aws-autoscaling/blob/master/README.md

Configure scaling policies by defining a map for `scaling_policies`. This example shows a Target Tracking Scaling policy based on average CPU utilization.

```hcl
scaling_policies = {
  my-policy = {
    policy_type               = "TargetTrackingScaling"
    target_tracking_configuration = {
      predefined_metric_specification = {
        predefined_metric_type = "ASGAverageCPUUtilization"
        resource_label         = "MyLabel"
      }
      target_value = 50.0
    }
  }
}
```

--------------------------------

### Autoscaling Group Configuration Before v7.x

Source: https://github.com/terraform-aws-modules/terraform-aws-autoscaling/blob/master/docs/UPGRADE-8.0.md

This example shows the configuration for traffic source attachment in versions prior to 7.x, using deprecated variables.

```hcl
module "asg" {
  source  = "terraform-aws-modules/autoscaling/aws"
  version = "~> 7.0"

  # Truncated for brevity

  # Traffic source attachment
  create_traffic_source_attachment = true
  traffic_source_identifier        = "arn:aws:elasticloadbalancing:us-east-2:123456789012:loadbalancer/app/my-load-balancer/1234567890123456"
  traffic_source_type              = "elbv2"

  ...
}
```

--------------------------------

### Autoscaling Module Configuration After v5.x

Source: https://github.com/terraform-aws-modules/terraform-aws-autoscaling/blob/master/docs/UPGRADE-5.0.md

This example demonstrates the updated configuration for the autoscaling module in version 5.x, reflecting the removal of launch configuration specific settings and changes in tag management.

```hcl
module "asg" {
  source  = "terraform-aws-modules/autoscaling/aws"
  version = "~> 5.0"

  # Autoscaling group
  name = "example-asg"

  min_size            = 0
  max_size            = 1
  desired_capacity    = 1
  health_check_type   = "EC2"
  vpc_zone_identifier = ["subnet-1235678", "subnet-87654321"]

  # Launch template
  launch_template_name        = "example-asg"
  launch_template_description = "Launch template example"
  update_default_version      = true

  image_id      = "ami-ebd02392"
  instance_type = "t3.micro"

  tags = {
    extra_tag1 = "extra_value1"
    extra_tag2 = "extra_value2"
  }
}
```

--------------------------------

### Basic IAM Role Creation for ASG

Source: https://github.com/terraform-aws-modules/terraform-aws-autoscaling/blob/master/_autodocs/api-reference/iam-instance-profile.md

Example of creating a basic IAM role and instance profile for an Auto Scaling group. This snippet demonstrates setting the role name and description.

```hcl
module "asg" {
  source = "terraform-aws-modules/autoscaling/aws"

  name = "asg-with-iam"
  # ... other configuration ...
  
  create_iam_instance_profile = true
  iam_role_name               = "asg-role"
  iam_role_description        = "Role for ASG instances"
  
  iam_role_policies = {
    "CloudWatchAgentServerPolicy" = "arn:aws:iam::aws:policy/CloudWatchAgentServerPolicy"
  }
}
```

--------------------------------

### Configure Development Environment Off-Hours Scaling

Source: https://github.com/terraform-aws-modules/terraform-aws-autoscaling/blob/master/_autodocs/api-reference/schedules.md

Implement minimal scaling for development environments during off-hours and weekends to save costs. This example sets a low desired capacity outside of typical working hours.

```HCL
module "dev_asg" {
  source = "terraform-aws-modules/autoscaling/aws"

  name = "dev-asg"
  min_size = 1
  max_size = 5
  # ... other configuration ...
  
  schedules = {
    scale_up_work_hours = {
      desired_capacity = 3
      recurrence       = "0 6 ? * MON-FRI"
      time_zone        = "America/New_York"
    }
    scale_down_off_hours = {
      desired_capacity = 1
      recurrence       = "0 20 ? * MON-FRI"
      time_zone        = "America/New_York"
    }
    scale_down_weekends = {
      desired_capacity = 1
      recurrence       = "0 0 ? * SAT"
      time_zone        = "America/New_York"
    }
  }
}
```

--------------------------------

### Move Terraform State for `ignore_desired_capacity_changes` (Specific Example)

Source: https://github.com/terraform-aws-modules/terraform-aws-autoscaling/blob/master/docs/UPGRADE-5.0.md

The specific Terraform state move command corresponding to the example configuration update from v4.x to v5.x with `ignore_desired_capacity_changes` enabled.

```bash
terraform state mv 'module.example.aws_autoscaling_group.this[0]' 'module.example.aws_autoscaling_group.idc[0]'
```

--------------------------------

### Complete Security-Hardened IAM Instance Profile Example

Source: https://github.com/terraform-aws-modules/terraform-aws-autoscaling/blob/master/_autodocs/api-reference/iam-instance-profile.md

Configures a highly secure IAM instance profile and role for an Auto Scaling Group, adhering to the principle of least privilege with custom policies and tags.

```hcl
# Custom policy for least-privilege access
resource "aws_iam_policy" "app_policy" {
  name = "app-server-policy"
  
  policy = jsonencode({
    Version = "2012-10-17"
    Statement = [
      {
        Sid    = "S3AppDataAccess"
        Effect = "Allow"
        Action = [
          "s3:GetObject",
          "s3:PutObject"
        ]
        Resource = "${aws_s3_bucket.app_data.arn}/*"
      },
      {
        Sid    = "KMSDecryption"
        Effect = "Allow"
        Action = [
          "kms:Decrypt",
          "kms:GenerateDataKey"
        ]
        Resource = aws_kms_key.app.arn
      },
      {
        Sid    = "SecretsManagerAccess"
        Effect = "Allow"
        Action = [
          "secretsmanager:GetSecretValue"
        ]
        Resource = "arn:aws:secretsmanager:*:*:secret:app/*"
      }
    ]
  })
}

module "asg" {
  source = "terraform-aws-modules/autoscaling/aws"

  name = "secure-app-asg"
  # ... other configuration ...
  
  create_iam_instance_profile = true
  iam_role_name               = "secure-app-role"
  iam_role_path               = "/applications/"
  iam_role_description        = "Role for application servers with least-privilege access"
  
  iam_role_policies = {
    "AmazonSSMManagedInstanceCore"    = "arn:aws:iam::aws:policy/AmazonSSMManagedInstanceCore"
    "CloudWatchAgentServerPolicy"     = "arn:aws:iam::aws:policy/CloudWatchAgentServerPolicy"
    "AppServerPolicy"                 = aws_iam_policy.app_policy.arn
  }
  
  iam_role_tags = {
    Environment  = "production"
    Classification = "restricted"
    Compliance   = "pci-dss"
  }
}

resource "aws_s3_bucket" "app_data" {
  bucket = "app-data-bucket"
}

resource "aws_kms_key" "app" {
  description = "Key for app encryption"
}
```

--------------------------------

### Multiple Target Groups Attachment Example

Source: https://github.com/terraform-aws-modules/terraform-aws-autoscaling/blob/master/_autodocs/api-reference/traffic-source-attachment.md

Shows how to attach multiple target groups (e.g., for HTTP and gRPC traffic) to a single Auto Scaling group. This allows for more complex routing configurations.

```hcl
module "asg" {
  source = "terraform-aws-modules/autoscaling/aws"

  name = "multi-target-asg"
  # ... other configuration ...
  
  traffic_source_attachments = {
    http_tg = {
      traffic_source_identifier = aws_lb_target_group.http.arn
      traffic_source_type       = "elbv2"
    }
    grpc_tg = {
      traffic_source_identifier = aws_lb_target_group.grpc.arn
      traffic_source_type       = "elbv2"
    }
  }
}
```

--------------------------------

### Autoscaling Group Configuration Before v9.x

Source: https://github.com/terraform-aws-modules/terraform-aws-autoscaling/blob/master/docs/UPGRADE-9.0.md

Example of an autoscaling group configuration using version 8.x of the module, demonstrating the 'override' block directly within the 'autoscaling' module.

```hcl
module "asg" {
  source  = "terraform-aws-modules/autoscaling/aws"
  version = "~> 8.0"

  # Truncated for brevity

  override = [
    {
      instance_type     = "t3.nano"
      weighted_capacity = "2"
    },
    {
      instance_type     = "t3.medium"
      weighted_capacity = "1"
    },
  ]
  ...
}
```

--------------------------------

### Autoscaling Group Configuration After v8.x

Source: https://github.com/terraform-aws-modules/terraform-aws-autoscaling/blob/master/docs/UPGRADE-8.0.md

This example demonstrates the updated configuration for traffic source attachment in version 8.x, utilizing the new `traffic_source_attachments` variable.

```hcl
module "asg" {
  source  = "terraform-aws-modules/autoscaling/aws"
  version = "~> 8.0"

  # Truncated for brevity

  traffic_source_attachments = {
    ex-alb = {
      traffic_source_identifier = "arn:aws:elasticloadbalancing:us-east-2:123456789012:loadbalancer/app/my-load-balancer/1234567890123456"
      traffic_source_type       = "elbv2"
    }
    ...
  }
  ...
}
```

--------------------------------

### Simple Scaling Policy Example

Source: https://github.com/terraform-aws-modules/terraform-aws-autoscaling/blob/master/_autodocs/api-reference/scaling-policies.md

Defines two Simple Scaling policies, one for scaling up and one for scaling down, triggered by CloudWatch alarms. Ensure CloudWatch alarms are created to trigger these policies.

```hcl
module "asg" {
  source = "terraform-aws-modules/autoscaling/aws"

  name = "simple-scaling-asg"
  # ... other configuration ...
  
  scaling_policies = {
    scale_up = {
      name                = "scale-up"
      policy_type         = "SimpleScaling"
      adjustment_type     = "ChangeInCapacity"
      scaling_adjustment  = 1
      cooldown            = 300
    }
    scale_down = {
      name                = "scale-down"
      policy_type         = "SimpleScaling"
      adjustment_type     = "ChangeInCapacity"
      scaling_adjustment  = -1
      cooldown            = 600
    }
  }
}

# Create CloudWatch alarms to trigger these policies
resource "aws_cloudwatch_metric_alarm" "high_cpu" {
  alarm_name          = "asg-high-cpu"
  comparison_operator = "GreaterThanThreshold"
  evaluation_periods  = 2
  metric_name         = "CPUUtilization"
  namespace           = "AWS/EC2"
  period              = 300
  statistic           = "Average"
  threshold           = 80
  alarm_actions       = [module.asg.autoscaling_policy_arns["scale_up"]]
}

resource "aws_cloudwatch_metric_alarm" "low_cpu" {
  alarm_name          = "asg-low-cpu"
  comparison_operator = "LessThanThreshold"
  evaluation_periods  = 15
  metric_name         = "CPUUtilization"
  namespace           = "AWS/EC2"
  period              = 300
  statistic           = "Average"
  threshold           = 20
  alarm_actions       = [module.asg.autoscaling_policy_arns["scale_down"]]
}
```

--------------------------------

### Autoscaling Group Configuration After v9.x

Source: https://github.com/terraform-aws-modules/terraform-aws-autoscaling/blob/master/docs/UPGRADE-9.0.md

Example of an autoscaling group configuration using version 9.x of the module, showing the 'override' block now nested within the 'launch_template' block.

```hcl
module "asg" {
  source  = "terraform-aws-modules/autoscaling/aws"
  version = "~> 9.0"

  # Truncated for brevity
  launch_template = {
    override = [
      {
        instance_type     = "t3.nano"
        weighted_capacity = "2"
      },
      {
        instance_type     = "t3.medium"
        weighted_capacity = "1"
      },
    ]
  }
  ...
}
```

--------------------------------

### Usage Example: Business Hours Scaling

Source: https://github.com/terraform-aws-modules/terraform-aws-autoscaling/blob/master/_autodocs/api-reference/schedules.md

Demonstrates configuring multiple scheduled actions for an Auto Scaling group to manage capacity during business hours and weekends. Includes scaling up in the morning and scaling down in the evening/weekends.

```hcl
module "asg" {
  source = "terraform-aws-modules/autoscaling/aws"

  name = "business-hours-asg"
  # ... other configuration ...
  
  schedules = {
    scale_up_morning = {
      desired_capacity = 10
      min_size         = 5
      max_size         = 20
      recurrence       = "0 8 ? * MON-FRI"
      time_zone        = "America/New_York"
    }
    scale_down_evening = {
      desired_capacity = 2
      min_size         = 1
      max_size         = 20
      recurrence       = "0 18 ? * MON-FRI"
      time_zone        = "America/New_York"
    }
    scale_down_weekend = {
      desired_capacity = 1
      min_size         = 1
      max_size         = 20
      recurrence       = "0 0 ? * SAT"
      time_zone        = "America/New_York"
    }
  }
}
```

--------------------------------

### Terraform Autoscaling Module Usage Example

Source: https://github.com/terraform-aws-modules/terraform-aws-autoscaling/blob/master/_autodocs/outputs.md

Demonstrates how to configure and use the Terraform AWS Autoscaling module, including defining basic ASG parameters and outputting key identifiers like the autoscaling group ID, launch template ID, and IAM role ARN.

```hcl
module "asg" {
  source = "terraform-aws-modules/autoscaling/aws"
  
  name = "example-asg"
  min_size = 1
  max_size = 3
  desired_capacity = 2
  vpc_zone_identifier = ["subnet-123", "subnet-456"]
  image_id = "ami-123456"
  instance_type = "t3.micro"
}

output "asg_id" {
  value = module.asg.autoscaling_group_id
}

output "launch_template_id" {
  value = module.asg.launch_template_id
}

output "iam_role_arn" {
  value = module.asg.iam_role_arn
}
```

--------------------------------

### Autoscaling Launch Template with Spot Instance Configuration

Source: https://github.com/terraform-aws-modules/terraform-aws-autoscaling/blob/master/_autodocs/api-reference/launch-template.md

Set up autoscaling groups to utilize spot instances, specifying the market type, maximum price, and instance interruption behavior.

```hcl
module "asg" {
  source = "terraform-aws-modules/autoscaling/aws"

  name          = "spot-asg"
  image_id      = "ami-0c55b159cbfafe1f0"
  instance_type = "t3.medium"
  
  instance_market_options = {
    market_type = "spot"
    spot_options = {
      max_price                      = "0.05"
      spot_instance_type             = "persistent"
      instance_interruption_behavior = "terminate"
    }
  }
  
  vpc_zone_identifier = ["subnet-123", "subnet-456"]
  min_size = 0
  max_size = 10
}
```

--------------------------------

### Example IAM Role Policies

Source: https://github.com/terraform-aws-modules/terraform-aws-autoscaling/blob/master/_autodocs/api-reference/iam-instance-profile.md

This map defines the policies to be attached to the IAM role. It maps policy names to their respective ARNs.

```hcl
iam_role_policies = {
  "AmazonSSMManagedInstanceCore" = "arn:aws:iam::aws:policy/AmazonSSMManagedInstanceCore"
  "CloudWatchAgentServerPolicy"  = "arn:aws:iam::aws:policy/CloudWatchAgentServerPolicy"
  "AmazonEC2ContainerRegistryReadOnly" = "arn:aws:iam::aws:policy/AmazonEC2ContainerRegistryReadOnly"
}
```

--------------------------------

### Autoscaling Launch Template with Security Best Practices

Source: https://github.com/terraform-aws-modules/terraform-aws-autoscaling/blob/master/_autodocs/api-reference/launch-template.md

Implement security best practices for autoscaling groups, including enforcing IMDSv2, enabling protection against termination and stop actions, and configuring encrypted EBS volumes.

```hcl
module "asg" {
  source = "terraform-aws-modules/autoscaling/aws"

  name = "secure-asg"
  image_id      = "ami-0c55b159cbfafe1f0"
  instance_type = "t3.medium"
  
  # IMDSv2 enforced (default)
  metadata_options = {
    http_endpoint               = "enabled"
    http_tokens                 = "required"
    http_put_response_hop_limit = 1
  }
  
  # Protection enabled
  disable_api_termination = true
  disable_api_stop        = true
  
  # Monitoring enabled
  enable_monitoring = true
  
  # Monitoring encryption
  block_device_mappings = [{
    device_name = "/dev/xvda"
    ebs = {
      encrypted   = true
      volume_type = "gp3"
      volume_size = 50
    }
  }]
  
  vpc_zone_identifier = ["subnet-123"]
  create_iam_instance_profile = true
  
  min_size = 1
  max_size = 3
}
```

--------------------------------

### Use External Launch Template

Source: https://github.com/terraform-aws-modules/terraform-aws-autoscaling/blob/master/README.md

Set `create_launch_template` to `false` and provide the name of an existing launch template to create an autoscaling group with it.

```hcl
create_launch_template = false
launch_template        = aws_launch_template.my_launch_template.name
```

--------------------------------

### Common Managed Policies for IAM Roles

Source: https://github.com/terraform-aws-modules/terraform-aws-autoscaling/blob/master/_autodocs/api-reference/iam-instance-profile.md

Examples of common AWS managed policies that can be assigned to IAM roles for specific use cases.

```hcl
iam_role_policies = {
  "AmazonSSMManagedInstanceCore" = "arn:aws:iam::aws:policy/AmazonSSMManagedInstanceCore"
}
```

```hcl
iam_role_policies = {
  "CloudWatchAgentServerPolicy" = "arn:aws:iam::aws:policy/CloudWatchAgentServerPolicy"
}
```

```hcl
iam_role_policies = {
  "AmazonEC2ContainerRegistryReadOnly" = "arn:aws:iam::aws:policy/AmazonEC2ContainerRegistryReadOnly"
}
```

```hcl
iam_role_policies = {
  "AmazonS3ReadOnlyAccess" = "arn:aws:iam::aws:policy/AmazonS3ReadOnlyAccess"
}
```

```hcl
iam_role_policies = {
  "service-role/AmazonEC2ContainerServiceforEC2Role" = "arn:aws:iam::aws:policy/service-role/AmazonEC2ContainerServiceforEC2Role"
}
```

--------------------------------

### IAM Role with Custom Permissions Boundary

Source: https://github.com/terraform-aws-modules/terraform-aws-autoscaling/blob/master/_autodocs/api-reference/iam-instance-profile.md

Example of creating an IAM role with a custom permissions boundary to restrict the maximum permissions granted to instances.

```hcl
module "asg" {
  source = "terraform-aws-modules/autoscaling/aws"

  name = "asg-bounded"
  # ... other configuration ...
  
  create_iam_instance_profile = true
  iam_role_name               = "limited-role"
  iam_role_permissions_boundary = aws_iam_policy.max_permissions.arn
  
  iam_role_policies = {
    "AmazonSSMManagedInstanceCore" = "arn:aws:iam::aws:policy/AmazonSSMManagedInstanceCore"
  }
}

resource "aws_iam_policy" "max_permissions" {
  name = "max-permissions-boundary"
  
  policy = jsonencode({
    Version = "2012-10-17"
    Statement = [
      {
        Effect = "Allow"
        Action = [
          "ec2:*",
          "s3:ListBucket",
          "cloudwatch:PutMetricData"
        ]
        Resource = "*"
      }
    ]
  })
}
```

--------------------------------

### Autoscaling Launch Template with Flexible Instance Type Selection

Source: https://github.com/terraform-aws-modules/terraform-aws-autoscaling/blob/master/_autodocs/api-reference/launch-template.md

Use this configuration to define autoscaling groups with flexible instance type requirements based on CPU and memory, allowing for a range of compatible instance types.

```hcl
module "asg" {
  source = "terraform-aws-modules/autoscaling/aws"

  name = "flexible-asg"
  
  instance_requirements = {
    vcpu_count = {
      min = 2
      max = 4
    }
    memory_mib = {
      min = 2048
      max = 8192
    }
    allowed_instance_types = ["t3.*", "m5.*"]
  }
  
  vpc_zone_identifier = ["subnet-123", "subnet-456"]
  min_size = 1
  max_size = 10
}
```

--------------------------------

### Recurring Schedule Example

Source: https://github.com/terraform-aws-modules/terraform-aws-autoscaling/blob/master/_autodocs/api-reference/schedules.md

Configures a recurring scheduled action using a cron expression and specifies a time zone. Requires 'recurrence' in cron format.

```hcl
schedules = {
  scale_up_weekdays = {
    desired_capacity = 5
    recurrence       = "0 8 ? * MON-FRI"
    time_zone        = "America/New_York"
  }
}
```

--------------------------------

### Configure Instance Placement

Source: https://github.com/terraform-aws-modules/terraform-aws-autoscaling/blob/master/_autodocs/api-reference/launch-template.md

Dynamically configure placement options for instances, such as availability zone, affinity, and placement group. Use this when specific placement strategies are required.

```HCL
dynamic "placement" {
  for_each = var.placement != null ? [var.placement] : []
}
```

--------------------------------

### Destroying Resources

Source: https://github.com/terraform-aws-modules/terraform-aws-autoscaling/blob/master/examples/complete/README.md

Command to destroy all resources created by the Terraform Auto Scaling Group examples. Use this when resources are no longer needed to avoid ongoing costs.

```bash
terraform destroy
```

--------------------------------

### Create Only Launch Template

Source: https://github.com/terraform-aws-modules/terraform-aws-autoscaling/blob/master/README.md

Set `create` to `false` to exclusively create a launch template without an autoscaling group.

```hcl
create = false
```

--------------------------------

### Configure Simple Scaling Policy

Source: https://github.com/terraform-aws-modules/terraform-aws-autoscaling/blob/master/_autodocs/api-reference/scaling-policies.md

Sets up a Simple Scaling policy for basic capacity adjustments. Use this for predictable scaling needs based on a single metric alarm.

```hcl
scaling_policies = {
  scale_up = {
    policy_type       = "SimpleScaling"
    adjustment_type   = "ChangeInCapacity"
    scaling_adjustment = 1
    cooldown          = 300
  }
}
```

--------------------------------

### Cron Expression Examples

Source: https://github.com/terraform-aws-modules/terraform-aws-autoscaling/blob/master/_autodocs/api-reference/schedules.md

Illustrates common cron expressions for AWS Auto Scaling scheduled actions, including daily, weekly, and interval-based schedules. Times are in UTC.

```text
0 8 ? * MON-FRI        # 8:00 AM weekdays
0 9 * * *              # Every day at 9:00 AM
0 8,12,18 * * *        # 8:00 AM, 12:00 PM, 6:00 PM every day
0 0 1 * *              # First day of month at midnight
30 2 ? * SUN           # 2:30 AM every Sunday
0/30 * * * *           # Every 30 minutes
```

--------------------------------

### Configure Metadata Options (IMDSv2)

Source: https://github.com/terraform-aws-modules/terraform-aws-autoscaling/blob/master/_autodocs/api-reference/launch-template.md

Set instance metadata service options, including enabling the endpoint, setting hop limits, and requiring tokens for IMDSv2. Defaults enforce security best practices.

```hcl
dynamic "metadata_options" {
  for_each = var.metadata_options != null ? [var.metadata_options] : []
}
```

```hcl
metadata_options = {
  http_endpoint               = "enabled"
  http_put_response_hop_limit = 1
  http_tokens                 = "required"
}
```

--------------------------------

### IAM Role for Container Registry Access

Source: https://github.com/terraform-aws-modules/terraform-aws-autoscaling/blob/master/_autodocs/api-reference/iam-instance-profile.md

Example of creating an IAM role for an Auto Scaling group to allow pulling container images from ECR. This is useful for containerized applications.

```hcl
module "asg" {
  source = "terraform-aws-modules/autoscaling/aws"

  name = "asg-with-ecr"
  # ... other configuration ...
  
  create_iam_instance_profile = true
  iam_role_name               = "asg-ecr-role"
  
  iam_role_policies = {
    "AmazonEC2ContainerRegistryReadOnly" = "arn:aws:iam::aws:policy/AmazonEC2ContainerRegistryReadOnly"
  }
}
```

--------------------------------

### Autoscaling Launch Template with Block Devices and Storage

Source: https://github.com/terraform-aws-modules/terraform-aws-autoscaling/blob/master/_autodocs/api-reference/launch-template.md

Configure autoscaling groups with specific block device mappings, including EBS volume details like size, type, encryption, and deletion on termination.

```hcl
module "asg" {
  source = "terraform-aws-modules/autoscaling/aws"

  name = "storage-asg"
  image_id      = "ami-0c55b159cbfafe1f0"
  instance_type = "m5.large"
  ebs_optimized = true
  
  block_device_mappings = [
    {
      device_name = "/dev/xvda"
      ebs = {
        volume_size           = 50
        volume_type           = "gp3"
        delete_on_termination = true
        encrypted             = true
        iops                  = 3000
        throughput            = 125
      }
    },
    {
      device_name = "/dev/sda1"
      ebs = {
        volume_size           = 100
        volume_type           = "gp3"
        delete_on_termination = true
      }
    }
  ]
  
  vpc_zone_identifier = ["subnet-123"]
  min_size = 1
  max_size = 5
}
```

--------------------------------

### Apply Tags to Resources

Source: https://github.com/terraform-aws-modules/terraform-aws-autoscaling/blob/master/_autodocs/api-reference/launch-template.md

Dynamically apply tags to various resources created from the launch template, including EC2 instances, EBS volumes, and spot requests. Specify the resource type and the tags to apply.

```HCL
dynamic "tag_specifications" {
  for_each = var.tag_specifications != null ? var.tag_specifications : []
}
```

--------------------------------

### aws_launch_template Resource Configuration

Source: https://github.com/terraform-aws-modules/terraform-aws-autoscaling/blob/master/_autodocs/api-reference/launch-template.md

This snippet outlines the configuration parameters for the `aws_launch_template` resource managed by the module. It covers core settings, AMI and instance type selection, instance requirements, IAM instance profiles, storage configurations, and CPU options.

```APIDOC
## Resource: aws_launch_template

### Description
Manages AWS EC2 Launch Templates with comprehensive instance configuration options. This resource is optionally created by the module when `create_launch_template` is set to `true`.

### Parameters

#### Core Configuration

- **region** (string, Optional) - AWS region. Defaults to provider region.
- **launch_template_name** (string, Optional) - Template name. Defaults to `var.name`.
- **launch_template_use_name_prefix** (bool, Optional) - Use name as prefix if true. Defaults to `true`.
- **launch_template_description** (string, Optional) - Template description. Defaults to `null`.
- **default_version** (string, Optional) - Default version number. Defaults to `null`.
- **update_default_version** (bool, Optional) - Update default version on each update. Defaults to `null`.

#### AMI and Instance Type

- **image_id** (string, Optional) - AMI ID (e.g., ami-0c55b159cbfafe1f0). Defaults to `null`.
- **instance_type** (string, Optional) - Instance type (e.g., t3.micro, m5.large). Cannot be used with `instance_requirements`. Defaults to `null`.
- **instance_initiated_shutdown_behavior** (string, Optional) - Shutdown behavior: "stop" or "terminate". Defaults to `null`.

#### Instance Requirements (Flexible Instance Type)

- **instance_requirements** (object, Optional) - Attribute-based instance requirements. Cannot be used with `instance_type`. Defaults to `null`.
  - **vcpu_count** (object, Optional) - {min, max} vCPU count.
  - **memory_mib** (object, Optional) - {min, max} RAM in MiB.
  - **allowed_instance_types** (list(string), Optional) - List of allowed types.
  - **excluded_instance_types** (list(string), Optional) - List of excluded types.
  - **require_hibernate_support** (bool, Optional) - Requires hibernate support.

#### IAM Instance Profile

- **iam_instance_profile_name** (string, Optional) - Name of the IAM instance profile.
- **iam_instance_profile_arn** (string, Optional) - ARN of the IAM instance profile.

#### Storage Configuration (Block Device Mappings)

- **block_device_mappings** (list(object), Optional) - List of block device mappings.
  - **device_name** (string, Optional) - Device name (e.g., /dev/xvda, /dev/sda1). Defaults to `null`.
  - **ebs** (object, Optional) - EBS volume configuration. Defaults to `null`.
    - **volume_size** (number, Optional) - Size in GiB.
    - **volume_type** (string, Optional) - gp2, gp3, io1, io2, st1, sc1.
    - **iops** (number, Optional) - IOPS (for gp3, io1, io2).
    - **throughput** (number, Optional) - Throughput MiB/s (for gp3).
    - **delete_on_termination** (bool, Optional) - Whether to delete on termination.
    - **encrypted** (bool, Optional) - Whether the EBS volume is encrypted.
    - **kms_key_id** (string, Optional) - KMS key ID for encryption.
    - **snapshot_id** (string, Optional) - Snapshot ID for volume creation.
  - **virtual_name** (string, Optional) - Virtual name for instance store. Defaults to `null`.
  - **no_device** (string, Optional) - Suppress device from AMI. Defaults to `null`.

#### CPU Options

- **cpu_options** (object, Optional) - CPU configuration options.
  - **core_count** (number, Optional) - Number of CPU cores. Defaults to `null`.
  - **threads_per_core** (number, Optional) - Threads per core (1 or 2). Defaults to `null`.
  - **amd_sev_snp** (string, Optional) - AMD SEV-SNP support. Defaults to `null`.
  - **nested_virtualization** (string, Optional) - Nested virtualization support. Defaults to `null`.

### Outputs

- **launch_template_id**
- **launch_template_name**
- **launch_template_arn**
- **launch_template_latest_version**
- **launch_template_default_version**
```

--------------------------------

### Launch Template Configuration

Source: https://github.com/terraform-aws-modules/terraform-aws-autoscaling/blob/master/_autodocs/api-reference/autoscaling-group.md

Use this block to specify an existing launch template for the autoscaling group. It cannot be used with a mixed instances policy.

```hcl
dynamic "launch_template" {
  for_each = var.use_mixed_instances_policy ? [] : [1]
  content {
    id      = local.launch_template_id
    version = local.launch_template_version
  }
}
```

--------------------------------

### Traffic Source Attachment for Classic Load Balancer (ELB)

Source: https://github.com/terraform-aws-modules/terraform-aws-autoscaling/blob/master/_autodocs/api-reference/traffic-source-attachment.md

Example configuration for attaching a classic load balancer to an Auto Scaling group. Use this for legacy deployments. The `traffic_source_identifier` is the name of the ELB.

```hcl
traffic_source_attachments = {
  classic_lb = {
    traffic_source_identifier = aws_elb.classic.name
    traffic_source_type       = "elb"
  }
}
```

--------------------------------

### Initial Lifecycle Hook Configuration

Source: https://github.com/terraform-aws-modules/terraform-aws-autoscaling/blob/master/_autodocs/api-reference/autoscaling-group.md

Define lifecycle hooks that execute during instance launch or termination. This block iterates over `initial_lifecycle_hooks` to set up multiple hooks.

```hcl
dynamic "initial_lifecycle_hook" {
  for_each = var.initial_lifecycle_hooks != null ? var.initial_lifecycle_hooks : []
  content {
    name                    = initial_lifecycle_hook.value.name
    lifecycle_transition    = initial_lifecycle_hook.value.lifecycle_transition
    default_result          = initial_lifecycle_hook.value.default_result
    heartbeat_timeout       = initial_lifecycle_hook.value.heartbeat_timeout
    notification_target_arn = initial_lifecycle_hook.value.notification_target_arn
    notification_metadata   = initial_lifecycle_hook.value.notification_metadata
    role_arn                = initial_lifecycle_hook.value.role_arn
  }
}
```

--------------------------------

### Using Externally Created Launch Configuration

Source: https://github.com/terraform-aws-modules/terraform-aws-autoscaling/blob/master/docs/UPGRADE-4.0.md

Configure these variables when you are managing the launch configuration outside of this module.

```hcl
  lc_name   = "externally-created"
  use_lc    = true
```

--------------------------------

### Automatic IAM Instance Profile Integration with Launch Template

Source: https://github.com/terraform-aws-modules/terraform-aws-autoscaling/blob/master/_autodocs/api-reference/iam-instance-profile.md

This dynamic block ensures that the specified or created IAM instance profile is automatically attached to the launch template. Instances launched using this template will inherit the profile.

```hcl
dynamic "iam_instance_profile" {
  for_each = local.iam_instance_profile_name != null || local.iam_instance_profile_arn != null ? [1] : []

  content {
    name = local.iam_instance_profile_name
    arn  = local.iam_instance_profile_arn
  }
}
```

--------------------------------

### Mixed Instances Policy Configuration

Source: https://github.com/terraform-aws-modules/terraform-aws-autoscaling/blob/master/_autodocs/api-reference/autoscaling-group.md

Enables flexible instance type selection with On-Demand and Spot pricing strategies. This block cannot be used with a regular launch template block.

```hcl
dynamic "mixed_instances_policy" {
  for_each = var.use_mixed_instances_policy ? [var.mixed_instances_policy] : []
  content {
    # instances_distribution configuration
    dynamic "launch_template" {
      # launch_template_specification with overrides
    }
  }
}
```

--------------------------------

### Traffic Source Attachment for Application/Network Load Balancer (ELBv2)

Source: https://github.com/terraform-aws-modules/terraform-aws-autoscaling/blob/master/_autodocs/api-reference/traffic-source-attachment.md

Example configuration for attaching an ALB or NLB target group to an Auto Scaling group. This is recommended for modern deployments. The `traffic_source_identifier` is the ARN of the target group.

```hcl
traffic_source_attachments = {
  alb_target_group = {
    traffic_source_identifier = aws_lb_target_group.app.arn
    traffic_source_type       = "elbv2"
  }
}
```

--------------------------------

### Configure a One-Time Event Schedule

Source: https://github.com/terraform-aws-modules/terraform-aws-autoscaling/blob/master/_autodocs/api-reference/schedules.md

Set up a single scaling event using `start_time` and `end_time` for temporary capacity adjustments. This is useful for promotions or planned maintenance.

```HCL
module "asg" {
  source = "terraform-aws-modules/autoscaling/aws"

  name = "event-asg"
  # ... other configuration ...
  
  schedules = {
    scale_for_promotion = {
      desired_capacity = 50
      min_size         = 25
      start_time       = "2024-12-20T00:00:00Z"
      end_time         = "2024-12-27T00:00:00Z"
    }
  }
}
```

--------------------------------

### Traffic Source Attachment for VPC Lattice Service Network

Source: https://github.com/terraform-aws-modules/terraform-aws-autoscaling/blob/master/_autodocs/api-reference/traffic-source-attachment.md

Example configuration for attaching a VPC Lattice service network to an Auto Scaling group. This is suitable for microservices architectures. The `traffic_source_identifier` is the ARN of the VPC Lattice service.

```hcl
traffic_source_attachments = {
  vpc_lattice = {
    traffic_source_identifier = aws_vpclattice_service_network.app.arn
    traffic_source_type       = "vpc-lattice"
  }
}
```

--------------------------------

### Set Launch Template Tags

Source: https://github.com/terraform-aws-modules/terraform-aws-autoscaling/blob/master/_autodocs/api-reference/launch-template.md

Assign additional tags directly to the launch template resource itself. These tags help in organizing and identifying the launch template.

```HCL
launch_template_tags = var.launch_template_tags
```

--------------------------------

### Terragrunt Example: Managing Multiple S3 Buckets

Source: https://github.com/terraform-aws-modules/terraform-aws-autoscaling/blob/master/wrappers/README.md

This Terragrunt configuration manages multiple S3 buckets using the autoscaling wrapper module. It sets default bucket configurations and defines specific settings for individual buckets.

```hcl
terraform {
  source = "tfr:///terraform-aws-modules/autoscaling/aws//wrappers"
  # Alternative source:
  # source = "git::git@github.com:terraform-aws-modules/terraform-aws-autoscaling.git//wrappers?ref=master"
}

inputs = {
  defaults = {
    force_destroy = true

    attach_elb_log_delivery_policy        = true
    attach_lb_log_delivery_policy         = true
    attach_deny_insecure_transport_policy = true
    attach_require_latest_tls_policy      = true
  }

  items = {
    bucket1 = {
      bucket = "my-random-bucket-1"
    }
    bucket2 = {
      bucket = "my-random-bucket-2"
      tags = {
        Secure = "probably"
      }
    }
  }
}
```

--------------------------------

### Module Creates Launch Configuration

Source: https://github.com/terraform-aws-modules/terraform-aws-autoscaling/blob/master/docs/UPGRADE-4.0.md

Use these variables when the module is responsible for creating the launch configuration. This is the default behavior for most use cases.

```hcl
  lc_name   = "module-will-create"
  use_lc    = true
  create_lc = true
```

--------------------------------

### Basic Autoscaling Group Deployment

Source: https://github.com/terraform-aws-modules/terraform-aws-autoscaling/blob/master/_autodocs/api-reference/autoscaling-group.md

Deploys a basic autoscaling group with specified capacity, network configuration, and launch template details. The launch template is created automatically by the module.

```hcl
module "asg" {
  source = "terraform-aws-modules/autoscaling/aws"

  name = "example-asg"
  
  # Capacity
  min_size         = 1
  max_size         = 5
  desired_capacity = 2
  
  # Network
  vpc_zone_identifier = ["subnet-abc123", "subnet-def456"]
  
  # Launch template (created automatically)
  image_id      = "ami-0c55b159cbfafe1f0"
  instance_type = "t3.micro"
  
  # Health
  health_check_type         = "ELB"
  health_check_grace_period = 300
  
  tags = {
    Environment = "production"
  }
}
```