t3
instances are burstable above baseline, so how does this have to be considered for auto-scaling by CPUUtilization
?
Let's say we use t3.small
instances with:
- 24 CPU credits earned per hour
- 2 vCPUs
- 20% Baseline performance per vCPU
I would set this scaling trigger for CPUUtilization
:
- Statistic: Average
- Unit: Percent
- Period: 5min
- Breach duration: 5min
- Upper threshold: 15%
- Lower threshold: 5%
So the upper threshold is set just below the baseline to avoid the additional cost when staying above the baseline for too long (and using up CPU credits).
In addition I set a CloudWatch alert when CPUUtilization
of any instance stays above 20% for too long. This would at least get triggered when auto scaling has reached the max. number of allowed instances.
Does this all make sense?