terraform.aws-baseline-infra/modules/ManagementGovernance/Monitoring.EC2/README.md

# Monitoring module 
This module deploys the default cloudwatch metric monitoring

## Notes
Terraform lifecycle ignores tags to speed up terraform subsequent update. Cloudwatch alarm tags cannot be read on aws console anyway.

## Example
```terraform
module "ec2-instances" {
  source        = "../../modules/util/resource-list"
  resource-type = "ec2"
}

module "ec2-monitoring" {
  cw-alarm-prefix            = local.cw-alarm-prefix
  for_each                   = module.ec2-instances.result-set
  source                     = "../../modules/ManagementGovernance/Monitoring.EC2"
  default-tags               = local.default-tags
  ec2-instance-id            = each.value
  threshold-CPUUtilization   = 90
  threshold-mem_free         = 100000
  threshold-swap_free        = 100000
  threshold-disk_free        = 1 * 1000 * 1000 * 1000
  threshold-disk_inodes_free = 10000
  threshold-processes_total  = 500
  threshold-LogicalDiskFreePct = 10
  threshold-MemoryCommittedPct = 90
  actions-enabled            = var.actions-enabled
  sns-targets = var.sns-targets
}
```

## Sample cloudwatch alarm email notification
```
Subject: ALARM: "TestAlarmPleaseIgnore" in Asia Pacific (Hong Kong)

You are receiving this email because your Amazon CloudWatch Alarm "TestAlarmPleaseIgnore" in the 
Asia Pacific (Hong Kong) region has entered the ALARM state, because "Threshold Crossed: 1 out of 
the last 1 datapoints [864.0 (24/01/24 00:56:00)] was less than or equal to the threshold (900.0) 
(minimum 1 datapoint for OK -> ALARM transition)." at "Wednesday 24 January, 2024 01:01:34 UTC".

View this alarm in the AWS Management Console:
https://ap-east-1.console.aws.amazon.com%2Fcloudwatch...

Alarm Details:
- Name:                       TestAlarmPleaseIgnore
- Description:                Cloudwatch alarm for the following resource
- Instance ID: xxx
- Instance Name: yyy
- Instance IP: zz.zz.zz.zz
- State Change:               OK -> ALARM
- Reason for State Change:    Threshold Crossed: 1 out of the last 1 datapoints [864.0 (24/01/24 00:56:00)] was less than or equal to the threshold (900.0) (minimum 1 datapoint for OK -> ALARM transition).
- Timestamp:                  Wednesday 24 January, 2024 01:01:34 UTC
- AWS Account:                111122223333
- Alarm Arn:                  arn:aws:cloudwatch:ap-east-1:111122223333:alarm:TestAlarmPleaseIgnore

Threshold:
- The alarm is in the ALARM state when the metric is LessThanOrEqualToThreshold 900.0 for at least 1 of the last 1 period(s) of 300 seconds.

Monitored Metric:
- MetricNamespace:                     AWS/EC2
- MetricName:                          CPUCreditBalance
- Dimensions:                          [InstanceId = i-050d4adeafaa53cd0]
- Period:                              300 seconds
- Statistic:                           Average
- Unit:                                not specified
- TreatMissingData:                    missing


State Change Actions:
- OK:
- ALARM: [arn:aws:sns:ap-east-1:111122223333:CWA-SNS-Email-KenFong]
- INSUFFICIENT_DATA:
```