When AWS autoscale doesn't

  • Scaling speed is limited. If the ratio of your actual metric value to target metric value is low, the maximum magnitude of a scale out event will get significantly limited.
  • Short cooldown periods can cause over-scaling or under-scaling because a scaling event may trigger before a previous scaling event has concluded.
  • Target tracking autoscaling works best in situations where at least one ECS service or CloudWatch metric is directly affected by the running task count, the metrics are bounded, or relatively stable and predictable.
  • The best way to find the right autoscaling strategy is to test it in your specific environment and against your specific load patterns.

Full post here, 8 mins read