Billing, Pricing, and Support practice questions

Reserved Instances exchange a one- or three-year commitment to specific instance attributes for discounts of up to 72 percent versus On-Demand; Standard RIs discount more deeply than Convertible RIs.

The scenario stacks every RI trigger: steady-state, 24/7, a known instance type that will not change, and a three-year horizon. Because the team does not need to exchange instance families during the term, the Standard offering class captures the largest discount, and the three-year term beats one year. On-Demand fails on cost, Spot fails because a stateful production database can never accept interruption, and a Capacity Reservation fails because it only guarantees capacity exists and charges the full On-Demand rate with no discount.

1. Spot the triggers: steady, predictable, 24/7, three-year horizon, fixed instance type.
2. Map those triggers to the commitment family: Reserved Instances or Savings Plans.
3. Choose Standard over Convertible because no instance-family change is expected, capturing the bigger discount.
4. Prefer the three-year term over one year for the deeper discount.
5. Eliminate Spot (interruption risk to a database) and Capacity Reservations (no discount).

Exam tip: Steady multi-year workloads with fixed instance needs earn the biggest discount from a three-year Standard RI.

Reserved Instances come in two offering classes: Standard (largest discount, limited flexibility) and Convertible (smaller discount, exchangeable for RIs with different instance family, operating system, or tenancy).

The deciding fact is the expected instance-family change during the term. A Standard RI would strand its discount the moment the workload moves to a new family, because Standard RIs cannot change family or operating system. Convertible RIs exist precisely for this case: you keep a meaningful discount and retain the right to exchange the reservation as needs evolve. Spot is irrelevant to commitment discounts, and a Capacity Reservation guarantees capacity without discounting anything, so neither addresses the requirement.

1. Note the two requirements: an RI discount and freedom to change instance family mid-term.
2. Recall the offering classes: Standard cannot change instance family; Convertible can be exchanged.
3. Accept the trade-off: Convertible discounts slightly less but survives the planned migration.
4. Eliminate the non-RI options, which either lack a discount or lack commitment pricing entirely.
5. Select Convertible Reserved Instances.

Exam tip: Expecting to change instance family during an RI term means Convertible, not Standard.

Reserved Instances offer three payment options that control how much of the commitment is paid at purchase: All Upfront, Partial Upfront, and No Upfront.

The rule is simple and directional: the more money you commit upfront, the deeper the discount. All Upfront pays the entire term at purchase and earns the largest discount, Partial Upfront sits in the middle, and No Upfront pays everything monthly for the smallest discount. Pay-as-you-go is a distractor drawn from On-Demand billing vocabulary; it is not an RI payment option at all.

1. Recall the three RI payment options: All, Partial, and No Upfront.
2. Apply the ordering rule: more paid upfront means a bigger discount.
3. Rank them: All Upfront beats Partial Upfront, which beats No Upfront.
4. Discard pay-as-you-go as On-Demand vocabulary, not an RI payment option.

Exam tip: RI discounts rank All Upfront over Partial Upfront over No Upfront.

A Reserved Instance is a pricing commitment, not a physical instance: for a one- or three-year term, matching usage in the account is billed at a discount of up to 72 percent versus On-Demand.

The two true statements capture the most-tested RI facts. First, an RI is a billing construct: the discount applies automatically to any running instance whose attributes (type, Region, platform, tenancy) match the reservation, and an unused RI still costs money. Second, RIs come in one-year and three-year terms with discounts up to 72 percent. The distractors transplant Spot facts onto RIs: AWS never launches an instance when you buy a reservation, never reclaims RI-covered capacity with a two-minute warning, and the 90 percent figure belongs exclusively to Spot.

1. Recall that an RI is purchased as a reservation and applied as a billing discount to matching running instances.
2. Recall the terms and discount ceiling: one or three years, up to 72 percent.
3. Reject the idea that purchasing an RI launches anything; unused RIs are wasted spend.
4. Reject the two-minute warning and the 90 percent figure as Spot-only facts.

Exam tip: An RI is a billing discount on matching instances, sold in 1- or 3-year terms at up to 72 percent off.

Savings Plans are commitment discounts where you promise a consistent hourly dollar spend on compute for one or three years, earning discounts of up to 72 percent versus On-Demand.

The defining feature of Savings Plans is what you commit to: money per hour, not machines. Eligible usage up to the hourly commitment bills at the discounted Savings Plans rate, and anything above it bills at normal On-Demand rates. The instance-attributes option describes Reserved Instances, which is precisely the model Savings Plans were designed to loosen. The data-transfer and minimum-uptime options invent commitments that do not exist in either model.

1. Recall the Savings Plans unit of commitment: dollars per hour of compute spend.
2. Recall the terms: one or three years, same as RIs, with up to 72 percent discounts.
3. Contrast with RIs, which commit to instance attributes rather than spend.
4. Eliminate options describing data transfer or uptime requirements, which are not commitment dimensions.

Exam tip: Savings Plans commit dollars per hour for 1 or 3 years; RIs commit instance attributes.

Compute Savings Plans are the most flexible commitment AWS sells: one hourly-spend commitment whose discount follows eligible compute usage across EC2 (any family, size, OS, tenancy, or Region), AWS Fargate, and AWS Lambda.

Two requirements narrow this to one answer: coverage across EC2, Fargate, and Lambda, and freedom to change instance families and Regions. Only the Compute Savings Plan satisfies both. The EC2 Instance Savings Plan offers a deeper discount but binds you to one instance family in one Region and excludes Fargate and Lambda. Standard RIs are even more rigid, locking specific instance attributes with no serverless coverage. Spot is not a commitment mechanism and cannot discount Lambda.

1. List the requirements: one commitment, covers EC2 plus Fargate plus Lambda, flexible across families and Regions.
2. Recall that Compute Savings Plans apply across all three services and every EC2 dimension.
3. Note that EC2 Instance Savings Plans trade that flexibility for a deeper discount within one family and Region.
4. Eliminate RIs and Spot, which neither cover serverless usage nor provide this flexibility.
5. Choose the Compute Savings Plan.

Exam tip: Mentions of Fargate or Lambda alongside EC2 flexibility point to a Compute Savings Plan.