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Amazon CloudWatch
User Guide

Amazon EC2 Metrics and Dimensions

Amazon Elastic Compute Cloud (Amazon EC2) sends metrics to CloudWatch for your EC2 instances. Basic (five-minute) monitoring is enabled by default. You can enable detailed (one-minute) monitoring. For information about additional metrics for Amazon EC2 instances that are in an Auto Scaling group, see Auto Scaling Metrics and Dimensions.

For more information about how to monitor Amazon EC2, see Monitoring Your Instances with CloudWatch in the Amazon EC2 User Guide for Linux Instances.

Amazon EC2 Metrics

The following metrics are available from each EC2 instance.

The AWS/EC2 namespace includes the following CPU credit metrics for your T2 instances.

Metric Description

CPUCreditUsage

[T2 instances] The number of CPU credits consumed by the instance. One CPU credit equals one vCPU running at 100% utilization for one minute or an equivalent combination of vCPUs, utilization, and time (for example, one vCPU running at 50% utilization for two minutes or two vCPUs running at 25% utilization for two minutes).

CPU credit metrics are available only at a 5 minute frequency. If you specify a period greater than five minutes, use the Sum statistic instead of the Average statistic.

Units: Count

CPUCreditBalance

[T2 instances] The number of CPU credits available for the instance to burst beyond its base CPU utilization. Credits are stored in the credit balance after they are earned and removed from the credit balance after they expire. Credits expire 24 hours after they are earned.

CPU credit metrics are available only at a 5 minute frequency.

Units: Count

The AWS/EC2 namespace includes the following instance metrics.

Metric Description

CPUUtilization

The percentage of allocated EC2 compute units that are currently in use on the instance. This metric identifies the processing power required to run an application upon a selected instance.

To use the percentiles statistic, you must enable detailed monitoring.

Depending on the instance type, tools in your operating system can show a lower percentage than CloudWatch when the instance is not allocated a full processor core.

Units: Percent

DiskReadOps

Completed read operations from all instance store volumes available to the instance in a specified period of time.

To calculate the average I/O operations per second (IOPS) for the period, divide the total operations in the period by the number of seconds in that period.

Units: Count

DiskWriteOps

Completed write operations to all instance store volumes available to the instance in a specified period of time.

To calculate the average I/O operations per second (IOPS) for the period, divide the total operations in the period by the number of seconds in that period.

Units: Count

DiskReadBytes

Bytes read from all instance store volumes available to the instance.

This metric is used to determine the volume of the data the application reads from the hard disk of the instance. This can be used to determine the speed of the application.

The number reported is the number of bytes received during the period. If you are using basic (five-minute) monitoring, you can divide this number by 300 to find Bytes/second. If you have detailed (one-minute) monitoring, divide it by 60.

Units: Bytes

DiskWriteBytes

Bytes written to all instance store volumes available to the instance.

This metric is used to determine the volume of the data the application writes onto the hard disk of the instance. This can be used to determine the speed of the application.

The number reported is the number of bytes received during the period. If you are using basic (five-minute) monitoring, you can divide this number by 300 to find Bytes/second. If you have detailed (one-minute) monitoring, divide it by 60.

Units: Bytes

NetworkIn

The number of bytes received on all network interfaces by the instance. This metric identifies the volume of incoming network traffic to a single instance.

The number reported is the number of bytes received during the period. If you are using basic (five-minute) monitoring, you can divide this number by 300 to find Bytes/second. If you have detailed (one-minute) monitoring, divide it by 60.

Units: Bytes

NetworkOut

The number of bytes sent out on all network interfaces by the instance. This metric identifies the volume of outgoing network traffic from a single instance.

The number reported is the number of bytes received during the period. If you are using basic (five-minute) monitoring, you can divide this number by 300 to find Bytes/second. If you have detailed (one-minute) monitoring, divide it by 60.

Units: Bytes

NetworkPacketsIn

The number of packets received on all network interfaces by the instance. This metric identifies the volume of incoming traffic in terms of the number of packets on a single instance. This metric is available for basic monitoring only.

Units: Count

Statistics: Minimum, Maximum, Average

NetworkPacketsOut

The number of packets sent out on all network interfaces by the instance. This metric identifies the volume of outgoing traffic in terms of the number of packets on a single instance. This metric is available for basic monitoring only.

Units: Count

Statistics: Minimum, Maximum, Average

The AWS/EC2 namespace includes the following status checks metrics. Status check metrics are available at a 1 minute frequency. For a newly-launched instance, status check metric data is only available after the instance has completed the initialization state (within a few minutes of the instance entering the running state). For more information about EC2 status checks, see Status Checks For Your Instances.

Metric Description

StatusCheckFailed

Reports whether the instance has passed both the instance status check and the system status check in the last minute.

This metric can be either 0 (passed) or 1 (failed).

Units: Count

StatusCheckFailed_Instance

Reports whether the instance has passed the instance status check in the last minute.

This metric can be either 0 (passed) or 1 (failed).

Units: Count

StatusCheckFailed_System

Reports whether the instance has passed the system status check in the last minute.

This metric can be either 0 (passed) or 1 (failed).

Units: Count

Amazon CloudWatch data for a new EC2 instance typically becomes available within one minute of the end of the first period of time requested (the aggregation period) in the query. You can set the period—the length of time over which statistics are aggregated—with the Period parameter. For more information on periods, see Periods.

You can use the currently available dimensions for EC2 instances (for example, ImageId or InstanceType) to refine the metrics returned. For information about the dimensions you can use with EC2, see Dimensions for Amazon EC2 Metrics.

Dimensions for Amazon EC2 Metrics

If you're using Detailed Monitoring, you can filter the EC2 instance data using any of the dimensions in the following table.

Dimension Description
AutoScalingGroupName

This dimension filters the data you request for all instances in a specified capacity group. An Auto Scaling group is a collection of instances you define if you're using Auto Scaling. This dimension is available only for Amazon EC2 metrics when the instances are in such an Auto Scaling group. Available for instances with Detailed or Basic Monitoring enabled.

ImageId

This dimension filters the data you request for all instances running this Amazon EC2 Amazon Machine Image (AMI). Available for instances with Detailed Monitoring enabled.

InstanceId

This dimension filters the data you request for the identified instance only. This helps you pinpoint an exact instance from which to monitor data.

InstanceType

This dimension filters the data you request for all instances running with this specified instance type. This helps you categorize your data by the type of instance running. For example, you might compare data from an m1.small instance and an m1.large instance to determine which has the better business value for your application. Available for instances with Detailed Monitoring enabled.