CODEWITHSUNDEEP
amazon-web-servicesamazon-ecsamazon-cloudwatchautoscaling
the-petrolhead
the-petrolhead

Reputation: 617

AWS High Resolution Metrics for faster ECS scaling

I have a complex REST API deployed in AWS ECS. The autoscaling policy for the same is based on RequestCount of 2000.

The scale out will happen when RequestCount is consistently higher than 2000 with standard resolution per 60 seconds. This takes at least 2 minutes before scaling happens. This is becoming a problem with short-time request surge when request count increases to 10k and above. The containers start rejecting requests(throttling).

I need to at least make the scaling happen more quickly within a minute if not within seconds. AWS CloudWatch seems to offer High-Resolution metrics, but there's very less information about:

  1. Can I enable specific metrics with high-resolution. Is it possible that I can have request counts resolved at high granularity of 5 seconds and CPUUtilization at standard granularity of 1 minute?

  2. How can I enable high resolution on AWS metrics?

The AWS CloudWatch Documentation seems to be insufficient to understand this process.

Upvotes: 1

Views: 993

Answers (1)

Shahad
Shahad

Reputation: 781

There's two different things that can be 'high resolution', the alarm and the metric.

A High Resolution metric just means the source is pushing values more frequently. You can't control this if your using an AWS metric, and most of them don't push more often than once a minute.

A High Resolution alarm is one where the period is less than 60 seconds and will be billed at a higher rate than standard alarms. However, this isn't very useful in most cases if the metric your basing it on only gets pushed once per minute

EDIT: To directly answer your questions

  1. No, I don't think any of the AWS RequestCount metrics for things like ELB have a 'high resolution on/off' toggle (although ELB might push more frequently than 1 minute by default, I'm not sure)
  2. its based on how often the source pushes data points to cloudwatch. If the AWS metrics don't work for what you need, you would need to add something like the CloudWatch agent (or just a script in your instance) pushing metric more frequently. Be careful about the CloudWatch API call charges if you do this from a lot of sources at a high frequency though

Upvotes: 1

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