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http://docs.aws.amazon.com/AWSEC2/latest/UserGuide/using-cloudwatch.html

Based on the above article and the FAQ, is there another article which can I help me better understand the near real time metrics and EC2 sending metric to Cloudwatch in 1-minute periods? The FAQ did state near real time for events and log, "CloudWatch Events is a near real time stream" and "With CloudWatch Logs, you can monitor your logs, in near real time".

Is it, EC2 will send metrics in 1-minute interval to Cloudwatch. Metric which trigger an alarm will be sent to cloudwatch in near real time, not wait for the 1-minute interval.
Thanks!

Yew Hang
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2 Answers2

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AWS have three levels of monitoring frequency

  • "standard" the free tier 5 minute metrics
  • "detailed" the pay for version, 1 minute metrics
  • "high resolution" anything under 1 minute

You specifically asked about alarms. Under high resolution, alarms can be configured for as fast as 10 seconds.

See https://aws.amazon.com/about-aws/whats-new/2017/07/amazon-cloudwatch-introduces-high-resolution-custom-metrics-and-alarms/ for an overview

The normal limit for putMetric adding data is 3 per second see http://docs.aws.amazon.com/AmazonCloudWatch/latest/monitoring/cloudwatch_limits.html

Also you mentioned EC2 specific, default metrics such as CPU and disk. High resolution metrics are always custom metrics. AWS metrics are not high resolution

Metrics produced by AWS services are standard resolution by default. When you publish a custom metric, you can define it as either standard resolution or high resolution. When you publish a high-resolution metric, CloudWatch stores it with a resolution of 1 second, and you can read and retrieve it with a period of 1 second, 5 seconds, 10 seconds, 30 seconds, or any multiple of 60 seconds.

(see http://docs.aws.amazon.com/AmazonCloudWatch/latest/monitoring/publishingMetrics.html)

Vorsprung
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  • Thanks Vorsprung! I did not know AWS released high resolution in Jul. – Yew Hang Oct 02 '17 at 14:13
  • I will spend some time reading them up. The main point which puzzle me was "near real-time" and 1 minute. As John Hanley pointed out "Every minute means near real time for AWS services".. before the high resolution release. Thanks both of you. – Yew Hang Oct 02 '17 at 15:53
  • So, only the default is free, the others are pay per use? – KumarAnkit Jan 28 '19 at 11:02
  • @KumarAnkit this answer is over a year old, you should look at the official AWS docs. It used to be the case that 5m resolution on ec2 was free and 1m was chargeable. – Vorsprung Jan 28 '19 at 14:44
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CloudWatch Events sends metrics to Amazon CloudWatch every minute.

This article from Amazon will help you with more details:

http://docs.aws.amazon.com/AmazonCloudWatch/latest/monitoring/cwe-metricscollected.html

John Hanley
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  • Thanks John for your quick response! Do you mean this list are the events which CloudWatch Events will sends every minutes, and all other events will be in near-real time? Eg: EC2 instances change state to running is in near-real time, include CPU, disk.. metrics? – Yew Hang Oct 02 '17 at 04:59
  • Every minute means near real time for AWS services. – John Hanley Oct 02 '17 at 06:35
  • That's one of possibility I thought of, but I can't seem to find supporting text in AWS to confirm it. With Vorsprung provided first AWS link; extracted "enabling you to monitor custom applications and infrastructure in near real-time, down to per-second resolution." .. I think you are right. – Yew Hang Oct 02 '17 at 14:10
  • Amazon is constantly improving / changing their services. I periodically read the FAQs and monitor the AWS Blog to stay on top of changes. For my job this takes an hour every day. StackOverflow is a good source of questions to monitor what people are actually doing / having problems with. – John Hanley Oct 02 '17 at 19:23
  • Please don’t mistook that I’m trying to poking fun of you with that example.. I just want to point out the wording used which imply this Jul 2017 release, AWS have updated the near real time for custom metric timing to 1sec… BTW, I read AWS update release notes few times and then I stop.. I need to learn the basic first. I've posted question here before; https://stackoverflow.com/questions/46035055/aws-small-setup-secured-public-access-idea-do-away-with-nat-gateway , but I should focus on the SAA exam first. Thanks. – Yew Hang Oct 04 '17 at 14:02