AWS Certified Generative AI Developer – Professional
Bedrock service tiers vs Provisioned Throughput for AIP-C01
On-demand requests run on the Standard tier unless you set service_tier to priority (faster, at a premium), flex (slower, at a discount) or reserved (capacity you reserve per month). Provisioned Throughput buys model units billed every hour until you delete it. Batch inference processes files of prompts from S3 asynchronously.
Service tiers
Set the optional service_tier parameter on a runtime call to reserved, priority, default or flex. Without it, requests go to Standard.
Priority gives the fastest response times at a price premium and needs no reservation. Its requests are served ahead of Standard and Flex. Flex gives a discount for workloads that can wait, such as evaluations and summarization.
Reserved lets you reserve input and output tokens-per-minute capacity for 1 or 3 months, with minimums of 100,000 input and 10,000 output TPM, billed monthly. Usage above the reservation overflows to Standard. Access is through your AWS account team.
Your on-demand quota is shared across priority, default and flex. The reserved capacity is separate. So a Flex job can use up the quota that a Standard or Priority assistant needs, and only a Reserved reservation takes the assistant out of that shared quota.
Provisioned Throughput
Provisioned Throughput buys model units (MUs). Each MU gives a set number of input and output tokens per minute. It is billed hourly whether or not you use it, and billing continues until you delete it.
Commitment can be none, 1 month or 6 months. A longer commitment gives a lower hourly price. With no commitment you can delete it at any time. With a term you can't delete it until the term ends.
Example: an HR assistant gets about 40 requests per business day on a no-commitment Provisioned Throughput. On-demand meets its latency needs, so deleting the Provisioned Throughput and calling the model ID stops paying for idle hours.
Batch inference
Batch inference takes prompts in files in S3, runs them asynchronously and writes the results to S3. It is not supported for provisioned models. Jobs with the Converse invocation type do not support tool calling. Bedrock sends job state changes to Amazon EventBridge, so you do not need to poll.
Where the exam catches people
Believing priority on the assistant stops throttling caused by a Flex job: priority, default and flex share one on-demand quota. Reserved capacity is separate.
Believing a lightly used Provisioned Throughput costs less when requests are smaller: it is billed hourly regardless of use.
Believing a cost-cutting change for an interactive chat can be batch inference: batch is asynchronous, so users would not get answers while they wait.
Believing Flex needs a new API or a reservation: it is the service_tier parameter on the same runtime call.
Believing a 1-month or 6-month Provisioned Throughput can be deleted early: it can't be deleted until the term is over.