Module: rds-cloudwatch-sns-alarms

Terraform module that configures important RDS alerts using CloudWatch and sends them to an SNS topic.

Create a set of sane RDS CloudWatch alerts for monitoring the health of an RDS instance.

Usage

area	metric	comparison operator	threshold	rationale
Storage	BurstBalance	<	20 %	20 % of credits allow you to burst for a few minutes which gives you enough time to a) fix the inefficiency, b) add capacity or c) switch to io1 storage type.
Storage	DiskQueueDepth	>	64	This number is calculated from our experience with RDS workloads.
Storage	FreeStorageSpace	<	2 GB	2 GB usually provides enough time to a) fix why so much space is consumed or b) add capacity. You can also modify this value to 10% of your database capacity.
CPU	CPUUtilization	>	80 %	Queuing theory tells us the latency increases exponentially with utilization. In practice, we see higher latency when utilization exceeds 80% and unacceptable high latency with utilization above 90%
CPU	CPUCreditBalance	<	20	One credit equals 1 minute of 100% usage of a vCPU. 20 credits should give you enough time to a) fix the inefficiency, b) add capacity or c) don't use t2 type.
Memory	FreeableMemory	<	64 MB	This number is calculated from our experience with RDS workloads.
Memory	SwapUsage	>	256 MB	Sometimes you can not entirely avoid swapping. But once the database accesses paged memory, it will slow down.

Examples

See the examples/ directory for working examples.

resource "aws_db_instance" "default" {
  allocated_storage    = 10
  storage_type         = "gp2"
  engine               = "mysql"
  engine_version       = "5.7"
  instance_class       = "db.t2.micro"
  identifier_prefix    = "rds-server-example"
  name                 = "mydb"
  username             = "foo"
  password             = "foobarbaz"
  parameter_group_name = "default.mysql5.7"
  apply_immediately    = "true"
  skip_final_snapshot  = "true"
}

module "rds_alarms" {
  source         = "git::https://github.com/cloudposse/terraform-aws-rds-cloudwatch-sns-alarms.git?ref=tags/0.1.5"
  db_instance_id = "${aws_db_instance.default.id}"
}