aws-burstable-break-even-calculator.py

#!/usr/bin/env python3
from icecream import ic

"""
Cost of burstable CPU credit above baseline:
- $0.09 per vCPU-Hour for Aurora Standard
- $0.12 per vCPU-Hour for Aurora I/O-Optimized clusters

Baseline cannot be foudn for aurora, but should be the same as ec2:
https://aws.amazon.com/ec2/instance-types/t4/
t4g.large: 30%
t4g.medium: 20%

Standard aurora pricing not I/O optimized

db.r7g.large pricing: $0.276 per h
db.t4g.large pricing: $0.146 per h
db.t4g.medium pricing: $0.073 per h
"""

def compute_break_even(
        r_price=0.276, # newer r7g price per hour
        t_price=0.073, # t4g.medium price per hour
        t_baseline=20, # % CPU included in the burstable
        t_vCPU=2, # Number of vCPUs of the burstable instance
        credit_price_per_h=0.09 # Price per vCPU hour
        ):
    tr_price_diff = r_price - t_price
    ic(tr_price_diff)
    credit_price_per_min = credit_price_per_h / 60
    # from price diff: possible burst in min (without including the baseline)
    burst_allowed_min = tr_price_diff / credit_price_per_min / t_vCPU
    ic(burst_allowed_min)
    burst_allowed_CPUusage = burst_allowed_min / 60 * 100
    ic(burst_allowed_CPUusage)
    break_even = burst_allowed_CPUusage + t_baseline
    return round(break_even, 2)

if __name__ == "__main__":
    print(compute_break_even())
    print(compute_break_even(t_price=0.164, t_baseline=30)) # db.t3.large vs db.r7g.large

    print(compute_break_even(r_price=0.260, t_price=0.164, t_baseline=30)) # db.t3.large vs db.r6g.large
    print(compute_break_even(r_price=0.260, t_price=0.146, t_baseline=30)) # db.t4g.large vs db.r6g.large

Results:

ic| tr_price_diff: 0.203
ic| burst_allowed_min: 67.66666666666667
ic| burst_allowed_CPUusage: 112.77777777777777
132.78
ic| tr_price_diff: 0.11200000000000002
ic| burst_allowed_min: 37.333333333333336
ic| burst_allowed_CPUusage: 62.22222222222222
92.22
ic| tr_price_diff: 0.096
ic| burst_allowed_min: 32.0
ic| burst_allowed_CPUusage: 53.333333333333336
83.33
ic| tr_price_diff: 0.11400000000000002
ic| burst_allowed_min: 38.00000000000001
ic| burst_allowed_CPUusage: 63.33333333333334
93.33