Terraform module that configures important RDS alerts using CloudWatch and sends them to the chosen SNS topic.
Create a set of sane RDS CloudWatch alerts for monitoring the health of an RDS instance.
| 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. |
The module will also alert on failure type events. See https://docs.aws.amazon.com/AmazonRDS/latest/UserGuide/USER_Events.html for a list of events.
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/ceibo-it/terraform-aws-rds-cloudwatch-sns-alarms.git?ref=tags/0.0.1"
db_instance_ids = [aws_db_instance.default.id]
aws_sns_topic_arn = aws_sns_topic.default.arn
}| Name | Description | Type | Default | Required |
|---|---|---|---|---|
| db_instance_ids | The instance IDs of the RDS database instance that you want to monitor. | list | - | yes |
| aws_sns_topic_arn | ARN of SNS topic to use. | string | - | yes |
| name_prefix | Alarm name prefix for each alarm. | string | `` | no |
| period | The threshold is analyzed over the last X seconds, where X is alarm_period | string | 600 |
no |
| evaluation_periods | The number of periods over which data is compared to the specified threshold. | string | 1 |
no |
| burst_balance_threshold | The minimum percent of General Purpose SSD (gp2) burst-bucket I/O credits available. | string | 20 |
no |
| cpu_credit_balance_threshold | The minimum number of CPU credits (t2 instances only) available. | string | 20 |
no |
| cpu_utilization_threshold | The maximum percentage of CPU utilization. | string | 80 |
no |
| disk_queue_depth_threshold | The maximum number of outstanding IOs (read/write requests) waiting to access the disk. | string | 64 |
no |
| free_storage_space_threshold | The minimum amount of available storage space in Byte. | string | 2000000000 |
no |
| freeable_memory_threshold | The minimum amount of available random access memory in Byte. | string | 64000000 |
no |
| swap_usage_threshold | The maximum amount of swap space used on the DB instance in Byte. | string | 256000000 |
no |
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terraform-aws-rds-cloudwatch-sns-alarms Copyright 2020 Ceibo
This product includes software developed by Cloud Posse, LLC (c) (https://cloudposse.com/) Licensed under Apache License, Version 2.0 Copyright © 2017-2019 Cloud Posse, LLC