Service/Amazon/Ec2/CloudWatch.php

ImageId: This dimension filters the data you request for all instances running this EC2 Amazon Machine Image (AMI).

AvailabilityZone: This dimension filters the data you request for all instances running in that EC2 Availability Zone.

AutoScalingGroupName: This dimension filters the data you request for all instances in a specified capacity group. An AutoScalingGroup is a collection of instances defined by customers of the Auto Scaling service. This dimension is only available for EC2 metrics when the instances are in such an AutoScalingGroup.

InstanceId: This dimension filters the data you request for only the identified instance. This allows a user to 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 allows a user to catagorize his data by the type of instance running. For example, a user might compare data from an m1.small instance and an m1.large instance to determine which has the better business value for his application.

LoadBalancerName: This dimension filters the data you request for the specified LoadBalancer name. A LoadBalancer is represented by a DNS name and provides the single destination to which all requests intended for your application should be directed. This metric allows you to examine data from all instances connected to a single LoadBalancer.

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.

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

NetworkOut: The number of bytes sent out on all network interfaces by the instance. This metric identifies the volume of outgoing network traffic to an application on a single instance.

DiskWriteOps: Completed write operations to all hard disks available to the instance. This metric identifies the rate at which an application writes to a hard disk. This can be used to determine the speed in which an application saves data to a hard disk.

DiskReadBytes: Bytes read from all disks 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 for the customer.

DiskReadOps: Completed read operations from all disks available to the instances. This metric identifies the rate at which an application reads a disk. This can be used to determine the speed in which an application reads data from a hard disk.

DiskWriteBytes: Bytes written to all disks 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 for the customer.

Latency: Time taken between a request and the corresponding response as seen by the load balancer.

RequestCount: The number of requests processed by the LoadBalancer.

HealthyHostCount: The number of healthy instances. Both Load Balancing dimensions, LoadBalancerName and AvailabilityZone, should be specified when retreiving HealthyHostCount.

UnHealthyHostCount: The number of unhealthy instances. Both Load Balancing dimensions, LoadBalancerName and AvailabilityZone, should be specified when retreiving UnHealthyHostCount.

Amazon CloudWatch data for a new EC2 instance becomes available typically within one minute of the end of the first aggregation period for the new instance. You can use the currently available dimensions for EC2 instances along with these metrics in order to refine the slice of data you want returned, such as metric CPUUtilization and dimension ImageId to get all CPUUtilization data for instances using the specified AMI.

The following table lists the statistics that you can request:

Minimum: The lowest value observed during the specified period. This can be used to determine low volumes of activity for your application.

Maximum: The highest value observed during the specified period. You can use this to determine high volumes of activity for your application.

Sum: The sum of all values received (if appropriate, for example a rate would not be summed, but a number of items would be). This statistic is useful for determining the total volume of a metric.

Average: The Average of all values received during the specified period. By comparing this statistic with the minimum and maximum statistics, you can determine the full scope of a metric and how close the average use is to the minimum and the maximum. This will allow you to increase or decrease your resources as needed.

Samples: The count (number) of measures used. This statistic is always returned to show the user the size of the dataset collected. This will allow the user to properly weight the data.

Statistics are computed within a period you specify, such as all CPUUtilization within a five minute period. At a minimum, all data is aggregated into one minute intervals. This is the minimum resolution of the data. It is this data that can be aggregated into larger periods of time that you request.

Aggregate data is generally available from the service within one minute from the end of the aggregation period. Delays in data propagation might cause late or partially late data in some cases. If your data is delayed, you should check the service’s Health Dashboard for any current operational issues with either Amazon CloudWatch or the services collecting the data, such as EC2 or Elastic Load Balancing.