tf_aws_ec2_auto_recovery

A Terraform template for EC2 Auto Recovery

This terraform module implements

• Auto Recovery for Amazon EC2
• Route53 Healthchecks and Failover

This is useful when

• You need to have a group of EC2 instances that need static public IPs (EIP)
• The software on EC2 instances is relatively reliable and you only need to worry about EC2 system errors
• EC2 instances type is one of C3, C4, M3, R3, and T2

Alternatives

• When static IP (EIP) is not needed, ELB with auto scaling group should be considered.
• An auto scaling group with (1,1,1) configured and attach EIP at provision time. (need IAM role for instance)

Components

• aws_eip.eip: an EIP to be assigned to the EC2 instance
• aws_instance.instance: the EC2 instance
• aws_cloudwatch_metric_alarm.auto_recovery_alarm: the Cloudwatch alarm to trigger EC2 instance Auto Recovery
• aws_route53_health_check.route53_health_check: an HTTP health check for the health of the EC2 instance (Assuming the instance serves HTTP traffic and has a health check)
• aws_route53_record.route53_record: a Route53 record point to the EIP attached to the EC2 instnace with healthcheck.

Example

module "static-ip-ec2-instances" {
  source                 = "github.com/cxmcc/tf_aws_ec2_auto_recovery"
  count                  = 2
  domain                 = "static-ip.example.com"
  route53_hosted_zone_id = "ZZZZFFFFEEEENNNN"
  ami                    = "ami-1234567"
  health_check_path      = "/route53_health_check"
  instance_type          = "m3.medium"
  name                   = "static-ip-instance"
  key_name               = "default"
  subnet_ids             = ["subnet-123456", "subnet-234567"]
  vpc_security_group_ids = ["sg-1234567"]

  user_data = <<EOF
#cloud-config
hostname: static-ip-instance
manage_etc_hosts: true
EOF
}