# Amazon CloudWatch alarms for cluster metrics
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AWS ParallelCluster configures Amazon CloudWatch alarms to monitor the health and resource utilization of the head node. Alarms are named `{{cluster-name}}-HeadNode-{{metric}}`, where {{cluster-name}} is the name of your cluster and {{metric}} identifies the metric being monitored.

Access the alarms in the CloudWatch console by choosing **Alarms** in the navigation pane.

A composite alarm named `{{cluster-name}}-HeadNode` enters the `ALARM` state when any of the individual head node alarms triggers.

## Disk and memory alarms
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Starting with AWS ParallelCluster version 3.6.0, the following CloudWatch alarms are created:
+ `{{cluster-name}}-HeadNode-Disk` — Monitors the root volume `disk_used_percent` metric. Enters the `ALARM` state when disk usage is greater than 90% for 1 data point within a 1 minute period.
+ `{{cluster-name}}-HeadNode-Mem` — Monitors the `mem_used_percent` metric. Enters the `ALARM` state when memory usage is greater than 90% for 1 data point within a 1 minute period.

For more information, see [Metrics collected by the CloudWatch agent](https://docs.aws.amazon.com/AmazonCloudWatch/latest/monitoring/metrics-collected-by-CloudWatch-agent.html) in the *Amazon CloudWatch User Guide*.

## Health check and CPU alarms
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Starting with AWS ParallelCluster version 3.8.0, the following CloudWatch alarms are created:
+ `{{cluster-name}}-HeadNode-Health` — Monitors the Amazon EC2 `StatusCheckFailed` metric. Enters the `ALARM` state when the value is greater than 0 for 1 data point within a 1 minute period.
+ `{{cluster-name}}-HeadNode-Cpu` — Monitors the Amazon EC2 `CPUUtilization` metric. Enters the `ALARM` state when CPU utilization is greater than 90% for 1 data point within a 1 minute period.

## Cluster management daemon heartbeat alarm
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Starting with AWS ParallelCluster version 3.15.0, when Amazon CloudWatch logging is enabled and the Slurm scheduler is used, the following alarm is created:
+ `{{cluster-name}}-HeadNode-ClustermgtdHeartbeat` — Monitors the `ClustermgtdHeartbeat` metric in the `ParallelCluster` namespace. The alarm enters the `ALARM` state when fewer than 1 heartbeat is received for 10 consecutive data points within a 1 minute period. Missing data is treated as breaching.

**Note**  
All alarms recover symmetrically: the same data points and evaluation period that trigger the alarm also govern recovery. For example, alarms with 1 data point recover after 1 good data point within the same observation period, similarly the `ClustermgtdHeartbeat` alarm requires 10 consecutive good data points (10 minutes) to return to `OK`.

**Note**  
AWS ParallelCluster doesn't configure alarm actions. For information about how to set up alarm actions, such as sending notifications, see [Alarm actions](https://docs.aws.amazon.com/AmazonCloudWatch/latest/monitoring/AlarmThatSendsEmail.html#alarms-and-actions). For more information about Amazon CloudWatch alarms, see [Using Amazon CloudWatch alarms](https://docs.aws.amazon.com/AmazonCloudWatch/latest/monitoring/AlarmThatSendsEmail.html) in the *Amazon CloudWatch User Guide*.  
For AWS ParallelCluster version 3.8.0 and later, disable alarms by setting [`Monitoring`](Monitoring-v3.md) / [`Alarms`](Monitoring-v3.md#yaml-Monitoring-Alarms) / [`Enabled`](Monitoring-v3.md#yaml-Monitoring-Alarms-Enabled) to `false` in your cluster configuration.  
For AWS ParallelCluster versions before 3.8.0, disable alarms by setting [`Monitoring`](Monitoring-v3.md) / [`Dashboards`](Monitoring-v3.md#yaml-Monitoring-Dashboards) / [`CloudWatch`](Monitoring-v3.md#yaml-Monitoring-Dashboard-CloudWatch) / [`Enabled`](Monitoring-v3.md#yaml-Monitoring-Dashboard-CloudWatch-Enabled) to `false` in your cluster configuration. Note that this setting also disables the Amazon CloudWatch dashboard. See [Amazon CloudWatch dashboard](cloudwatch-dashboard-v3.md) for additional details.