Mixed practice exam 5

Explanation

Answer: A. Compute Savings Plans are the most flexible commitment AWS offers. The plan is a dollars-per-hour commitment that is applied automatically to eligible usage across EC2 instance families, sizes, Regions, operating systems, and tenancies, and across AWS Fargate and AWS Lambda as well. Because the discount follows the workload rather than a fixed configuration, Compute Savings Plans suit organizations that expect to modernize or shift workloads during the term.

• B. There is no resale marketplace for Savings Plans. A limited resale mechanism exists for certain Reserved Instances, not for Savings Plans.
• C. Being locked to one instance family and Region describes EC2 Instance Savings Plans, which trade that narrower scope for a deeper discount of up to 72%.
• D. No Savings Plan reserves capacity. Capacity assurance in a specific Availability Zone comes from zonal Reserved Instances or On-Demand Capacity Reservations.

Explanation

Answer: D. Both options give single-tenant hardware, but only Dedicated Hosts expose the physical server's sockets, cores, and host ID. That visibility is what allows customers to bring licenses that are counted per socket, per core, or per VM. Dedicated Hosts are billed per host and add host affinity and targeted instance placement. Dedicated Instances are billed per instance, support a narrower set of BYOL scenarios such as SQL Server with License Mobility, and offer no placement control.

• A. This reverses the billing models. Dedicated Hosts carry a per-host charge; Dedicated Instances carry a per-instance charge plus a per-Region fee for dedicated tenancy.
• B. This reverses the two. Dedicated Instances are the option that provides isolation without hardware visibility.
• C. Host affinity and targeted instance placement are Dedicated Hosts features only. Dedicated Instances do not support them, so price is not the only difference.

Explanation

Answer: B and C. Spot Instances draw on unused Amazon EC2 capacity, which is why AWS can price them at up to 90% below On-Demand. The price of that discount is reclaimability: when AWS needs the capacity for On-Demand or committed-use customers, it interrupts the Spot Instance after a two-minute warning. Understanding both halves together, deep discount and interruptibility, is what lets a candidate decide whether a workload belongs on Spot.

• A. Spot prices adjust gradually based on supply and demand for spare capacity, so the rate is not fixed for the life of the instance.
• D. Spot requires no term commitment at all. Commitments of 1 or 3 years belong to Reserved Instances and Savings Plans.
• E. Reserving capacity in a specific Availability Zone is the function of a zonal Reserved Instance or an On-Demand Capacity Reservation. Spot provides the opposite: capacity that AWS may take back.

Explanation

Answer: B. On-Demand Capacity Reservations reserve EC2 capacity in a specific Availability Zone for as long as the customer needs it, with no term commitment, and can be cancelled when the event ends. The reservation is billed at On-Demand rates whether or not instances are actually running in it, which is the cost of holding guaranteed capacity. This decoupling of capacity assurance from a long-term billing commitment is exactly the gap the feature fills.

• A. A capacity-optimized allocation strategy reduces the likelihood of Spot interruption but cannot guarantee capacity, since AWS reclaims Spot capacity when it is needed elsewhere.
• C. A Compute Savings Plan is a billing construct only. It provides no capacity assurance in any Availability Zone, and it also imposes the one-year commitment the company wants to avoid.
• D. A zonal Reserved Instance would reserve the capacity, but it locks the company into a one-year term for a three-week need, so the company would pay for roughly eleven months of unused commitment.

Explanation

Answer: B. The Standard and Convertible split is a trade of discount depth against flexibility. Standard reservations give the deepest Reserved Instance discount, and while they can be modified in limited ways such as changing the Availability Zone or scope, AWS documentation states they cannot be exchanged. Convertible reservations accept a smaller discount in return for the right to exchange into a reservation with different attributes, provided the new reservation is of equal or greater value.

• A. This reverses both halves of the trade-off. Convertible reservations are the flexible, less deeply discounted option.
• C. Standard Reserved Instances cannot be exchanged, and both types offer the same 1-year and 3-year terms, so term length is not the distinguishing factor.
• D. Reserved Instances can be modified within documented limits: changing the Availability Zone within the Region, changing the scope between zonal and regional, and changing instance size within the same instance family and generation.

Explanation

Answer: B. Scope determines whether a Reserved Instance carries a capacity reservation. Regional scope buys flexibility, meaning the discount applies in any Availability Zone in the Region and, for Linux/Unix with default tenancy, across sizes in the family, but AWS documentation states plainly that a regional Reserved Instance does not reserve capacity. Capacity assurance requires zonal scope or an On-Demand Capacity Reservation. Because zonal and regional Reserved Instances cost the same, the choice between them is purely about flexibility versus capacity assurance.

• A. Tenancy is an attribute the reservation must match to apply the discount. It does not turn a regional reservation into a capacity reservation.
• C. There is no waiting period after which a regional Reserved Instance begins reserving capacity. Regional scope never reserves capacity.
• D. The payment option affects only the discount and the cash-flow profile. It has no effect on capacity reservation behavior.

Explanation

Answer: B and C. Consolidated billing pools usage across the organization so that commitments are used as efficiently as possible. AWS applies a Reserved Instance or Savings Plans benefit to the owning account first, then makes any remaining benefit available to other accounts whose usage matches. The management account is the one that controls discount sharing preferences for accounts in the organization, which is what lets a central finance team decide whether commitments are pooled or ring-fenced.

• A. AWS warns that deactivating discount sharing can result in higher monthly bills, because unused commitment in one account can no longer offset matching usage in another.
• D. Commitments bought by a member account are shared across the organization by default once sharing is enabled; ownership determines priority, not eligibility.
• E. No Savings Plan reserves capacity anywhere. Savings Plans are purely a billing discount mechanism.

Explanation

Answer: C. Dedicated Instances run on hardware dedicated to a single AWS account, which satisfies the isolation requirement, and AWS documents SQL Server with License Mobility through Software Assurance as a supported bring-your-own-license scenario for them. Because the company needs neither hardware visibility nor placement control, Dedicated Instances deliver the requirement without the additional allocation and capacity management that Dedicated Hosts entail.

• A. Shared tenancy places instances on hardware that may be shared with other AWS accounts, which fails the isolation requirement outright.
• B. Placement groups control how instances are positioned relative to one another for networking and resilience. They do not provide single-tenant hardware, and Spot capacity can be reclaimed at any time.
• D. Dedicated Hosts would satisfy the requirement, but they require the customer to allocate and manage host capacity and to track instance placement, which is unnecessary overhead when no per-socket or per-core license needs to be accounted for.

Explanation

Answer: D. Three variables drive the size of a Reserved Instance discount: term length, payment option, and offering class. The deepest discount comes from combining the longest term, the largest upfront payment, and the least flexible offering class. A 3-year Standard Reserved Instance paid All Upfront maximizes all three at once. AWS states directly that a longer term produces a bigger discount and that a higher upfront payment saves more money.

• A. A one-year term produces a noticeably smaller discount than a three-year term, and it leaves two years of the known workload uncovered.
• B. Convertible reservations sacrifice discount depth in exchange for the right to exchange the reservation later. With requirements known to be stable for three years, that flexibility is paid for and never used.
• C. No Upfront spreads the cost over discounted hourly charges across the term, which improves cash flow but produces the smallest discount of the three payment options.

Explanation

Answer: B. AWS does not charge for data transfer from the internet into AWS. This asymmetry is deliberate: it removes any cost penalty for moving data into the cloud, which supports migration and ingest-heavy workloads. Charges apply to data leaving AWS for the internet and to certain traffic between Availability Zones and Regions, so cost-aware architecture concentrates on egress and on where data crosses those boundaries.

• A. Inbound and outbound transfer are priced very differently. Outbound to the internet is metered and tiered; inbound is free.
• C. There is no half-rate inbound charge. Inbound data transfer from the internet is free of charge.
• D. The 100 GB per month free allowance applies to data transfer out to the internet, aggregated across AWS services and Regions, not to inbound transfer.