CloudWatch Overview / Namespaces, Metrics, and Dimensions |
This section discusses the Elastic Load Balancing (ELB) metrics and dimensions available to CloudWatch.
Metric | Description | Unit |
---|---|---|
Latency | Time elapsed after the request leaves the load balancer until it
receives the corresponding response. Valid Statistics: Minimum | Maximum | Average | Count |
Seconds |
RequestCount | The number of requests handled by the load balancer. | Count |
HealthyHostCount | The number of healthy instances registered with the load
balancer in a specified availability zone. Healthy instances are those that have not failed more health checks than the
value of the unhealthy threshold.
Constraints: You must provide both LoadBalancerName and AvailabilityZone dimensions for this metric. Valid Statistics: Minimum | Maximum | Average |
Count |
UnHealthyHostCount | The number of unhealthy instances registered with the
load balancer. These are instances that have failed more health checks than the
value of the unhealthy threshold.
Constraints: You must provide both LoadBalancerName and AvailabilityZone dimensions for this metric. Valid Statistics: Minimum | Maximum | Average |
Count |
HTTPCode_ELB_4XX | Count of HTTP response codes generated by ELB
that are in the 4xx (client error) series. Valid Statistics: Sum |
Count |
HTTPCode_ELB_5XX | Count of HTTP response codes generated by ELB
that are in the 5xx (server error) series. ELB
can generate 5xx errors if no back-end instances are registered, no
healthy back-end instances, or the request rate exceeds ELB's current available capacity. This response count does not
include any responses that were generated by back-end instances.
Valid Statistics: Sum |
Count |
HTTPCode_Backend_2XX | Count of HTTP response codes generated by back-end instances that
are in the 2xx (success) series. Valid Statistics: Sum |
Count |
HTTPCode_Backend_3XX | Count of HTTP response codes generated by back-end instances that
are in the 3xx (user action required) series. Valid Statistics: Sum |
Count |
HTTPCode_Backend_4XX | Count of HTTP response codes generated by back-end instances that
are in the 4xx (client error) series. This response count does not
include any responses that were generated by ELB. Valid Statistics: Sum |
Count |
HTTPCode_Backend_5XX | Count of HTTP response codes generated by back-end instances that are in the 5xx (server error) series. This response count does not include any responses that were generated by ELB.
Valid Statistics: Sum |
Count |
You can use the currently available dimensions for ELB 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 load balancer within the specified Availability Zone for a given period of time.
You can aggregate ELB data along any of the following dimensions shown in the following table.
Metric | Description |
---|---|
LoadBalancerName | Limits the metric data to instances that are connected to the specified load balancer. |
AvailabilityZone | Limits the metric data to load balancers in the specified availability zone. |