Common variables referenced in naming standards

• ALB

• ASG

If you followed the naming conventions listed in terraform-aws-vpc you will find it useful to use this terraform-aws-discovery module. The idea of using a discovery module is to centralize datasource usage in a central place and keep the source code DRY.

Here is an example usage:

module "discovery" {
  source              = "github.com/Lowess/terraform-aws-discovery"
  aws_region          = var.aws_region
  vpc_name            = var.vpc_name
  ec2_ami_names       = ["<AMI-NAME>"]
  ec2_ami_owners      = "<TEACHER-ACCOUNT-ID>"
  ec2_security_groups = [...]
}

☝️ If you do not what to use this module you are free to redefine the datasources you need but keep in mind that you will be rebuilding the wheel 🎡

Let's create an ALB and the related resources needed (security groups, listeners and target groups).

• aws_lb
• aws_lb_target_group
• aws_lb_listener
• aws_security_group
• aws_security_group_rule

• aws_security_group
• aws_security_group_rule
• aws_launch_template
• aws_autoscaling_group

  • ⚠️ Make sure you use vpc_zone_identifier and not availability_zones

  • ⚠️ Use min_size = 1 and max_size = 2 as AWS educate sets limits on your accounts !

• Visit the Cloudwatch service and discover what this service does

☝️ Think about what's the best metric to use in order to adjust the size of the Autoscaling group

• aws_autoscaling_policy

  • Define the scaling strategy (add / remove machines)

• aws_cloudwatch_metric_alarm

  • Define an alarm that will trigger the autoscaling policy