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Amazon CloudWatch collects measures for Amazon EC2 instances and Elastic Load Balancing.
The following metrics are available from each EC2 instance.
| 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. Units: Percent |
| 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. 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 to an application on a single instance. Units: Bytes |
| 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. Units: Count |
| 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. Units: Bytes |
| 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. Units: Count |
| 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. Units: Bytes |
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 use the currently available dimensions for EC2 instances (for example, ImageID or InstanceType) in order to refine the metrics returned.
For information about the dimensions you can use with EC2, see Amazon CloudWatch Dimensions.
The following metrics are available from the Elastic Load Balancing.
| Metric | Section |
|---|---|
| Latency | Time taken between a request and the corresponding response as seen by the load balancer. Units: Seconds Valid Statistics: Minimum, Maximum, Average and Count |
| RequestCount | The number of requests processed by the LoadBalancer. Units: Count/Second Valid Statistics: Minimum, Maximum and Sum |
| HealthyHostCount | The number of healthy instances. Both Load Balancing dimensions, LoadBalancerName and AvailabilityZone, should be specified when retrieving HealthyHostCount. Units: Count Valid Statistics: the Average for a LoadBalancer within an Availability Zone |
| UnHealthyHostCount | The number of unhealthy i. Both Load Balancing dimensions, LoadBalancerName and AvailabilityZone, should be specified when retrieving UnHealthyHostCount. Units: Count Valid Statistics: the Average for a LoadBalancer within an Availability Zone |
You can use the currently available dimensions for Elastic Load Balancing to refine the metrics returned by a query. For example, you could use HealthyHostCount and dimensions LoadBalancerName and AvailabilityZone to get the Average number of healthy Instances behind the specified LoadBalancer within the specified Availability Zone for a given period of time. For the dimensions you can use with the Load Balancing Service, see Amazon CloudWatch Dimensions
