CloudWatch Exporter

An exporter for Amazon CloudWatch, for Prometheus.

Building and running

mvn package to build.

java -jar target/cloudwatch_exporter-0.1-SNAPSHOT-jar-with-dependencies.jar 9106 example.yml to run.

Credentials and permissions

The CloudWatch Exporter uses the AWS Java SDK, which offers a variety of ways to provide credentials. This includes the AWS_ACCESS_KEY_ID and AWS_SECRET_ACCESS_KEY environment variables.

The cloudwatch:ListMetrics and cloudwatch:GetMetricStatistics IAM permissions are required.

Configuration

The configuration is in YAML, an example with common options:

---
region: eu-west-1
metrics:
 - aws_namespace: AWS/ELB
   aws_metric_name: RequestCount
   aws_dimensions: [AvailabilityZone, LoadBalancerName]
   aws_dimension_select:
     LoadBalancerName: [myLB]
   aws_statistics: [Sum]

Name	Description
region	Required. The AWS region to connect to.
role_arn	Optional. The AWS role to assume. Useful for retrieving cross account metrics.
metrics	Required. A list of CloudWatch metrics to retrieve and export
aws_namespace	Required. Namespace of the CloudWatch metric.
aws_metric_name	Required. Metric name of the CloudWatch metric.
aws_dimensions	Optional. Which dimension to fan out over.
aws_dimension_select	Optional. Which dimension values to filter. Specify a map from the dimension name to a list of values to select from that dimension.
aws_dimension_select_regex	Optional. Which dimension values to filter on with a regular expression. Specify a map from the dimension name to a list of regexes that will be applied to select from that dimension. This also tries to expand environment variables used as value, like ${CLOUDWATCH_REGEX} or even ${TMPDIR}.
aws_statistics	Optional. A list of statistics to retrieve, values can include Sum, SampleCount, Minimum, Maximum, Average. Defaults to all statistics.
delay_seconds	Optional. The newest data to request. Used to avoid collecting data that has not fully converged. Defaults to 600s. Can be set globally and per metric.
range_seconds	Optional. How far back to request data for. Useful for cases such as Billing metrics that are only set every few hours. Defaults to 600s. Can be set globally and per metric.
period_seconds	Optional. Period to request the metric for. Only the most recent data point is used. Defaults to 60s. Can be set globally and per metric.

The above config will export time series such as

# HELP aws_elb_request_count_sum CloudWatch metric AWS/ELB RequestCount Dimensions: ["AvailabilityZone","LoadBalancerName"] Statistic: Sum Unit: Count
# TYPE aws_elb_request_count_sum gauge
aws_elb_request_count_sum{job="aws_elb",load_balancer_name="mylb",availability_zone="eu-west-1c",} 42.0
aws_elb_request_count_sum{job="aws_elb",load_balancer_name="myotherlb",availability_zone="eu-west-1c",} 7.0

All metrics are exported as gauges.

Timestamps from CloudWatch are not passed to Prometheus, pending resolution of #398. CloudWatch has been observed to sometimes take minutes for reported values to converge. The default delay_seconds will result in data that is at least 5 minutes old being requested to mitigate this.

In addition cloudwatch_exporter_scrape_error will be non-zero if an error occurred during the scrape, and cloudwatch_exporter_scrape_duration_seconds contains the duration of that scrape.

Cost

Amazon charges for every API request, see the current charges.

Every metric retrieved requires one API request, which can include multiple statistics. In addition, when aws_dimensions is provided, the exporter needs to do API requests to determine what metrics to request. This should be negligible compared to the requests for the metrics themselves.

If you have 100 API requests every minute, with the price of USD$10 per million requests (as of Jan 2015), that is around $45 per month. The cloudwatch_requests_total counter tracks how many requests are being made.

Docker Image

To run the CloudWatch exporter on Docker, you can use the prom/cloudwatch-exporter image. It exposes port 9106 and expects the config in /config.yml. To configure it, you can either bind-mount a config from your host:

$ docker run -p 9106 -v /path/on/host/config.yml:/config.yml prom/cloudwatch-exporter

Or you create a config file named config.yml along with following Dockerfile in the same directory and build it with docker build:

FROM prom/cloudwatch-exporter