EC2 - Purchasing Options

Question 1

List all available EC2 Instance purchasing options

Answer 1

On Demand
Reserved Instance
Convertible Reserved Instance
Savings Plans
Spot Instances
Dedicated Hosts
Dedicated Instances
Capacity Reservations

Question 2

What use cases would On-Demand Instances be useful for?

Answer 2

Short-term and un-interrupted workloads, where you cannot predict how the application will behave

Question 3

What are the billing options for On-Demand Instances?

Answer 3

Linux or Windows are billed per second after the first minute.

All other OS’s are billed per hour

Question 4

What purchasing option has the highest cost but no upfront payment?

Answer 4

On Demand

Question 5

Is there a long-term commitment for On Demand Instances?

Answer 5

No. You only pay for what you use.

Question 6

How are Reserved Instances priced in comparison to On Demand?

Answer 6

They are heavily discounted. Can be up to 72%

Question 7

What are the instance attributes that are reserved for Reserved Instances?

Answer 7

Instance Type (e.g. General purpose, compute optimised)
Region
Tenancy (Host, Dedicated, Default)
OS

Question 8

What is the reservation period for Reserved Instances?

Answer 8

1 or 3 years. 3 years have a greater discount applied.

Question 9

What are the payment options for Reserved Instances?

Answer 9

No upfront, partially upfront and all upfront. With greater discounts being applied based on how large of an upfront payment there is.

Question 10

What use cases are Reserved Instances recommended for?

Answer 10

They are recommended long workloads and steady-state usage applications e.g. databases

Question 11

What is the name of the marketplace where you can buy and sell Reserved Instances?

Answer 11

Reserved Instance Marketplace

Question 12

What two ways does a Convertible Reserved Instance differ from a standard RI?

Answer 12

1. You can change the EC2 Instance type, family, OS, scope and tenancy.
2. You get less of a discount (up to 66% compared to On-Demand). This is because of the additional flexibility.

Question 13

What are the scopes you can set for a Reserved Instance?

Answer 13

Regional or Zonal (Reserve capacity in an AZ)

Question 14

How are EC2 Savings Plans discounted?

Answer 14

They are discounted based on long term usage (up to 72% compared to On-Demand)

Question 15

Which purchasing option requires you to commit to a certain type of usage? (e.g. $10/hour for 1 year)

Answer 15

Savings Plans

Question 16

At what price will any usage beyond the limit for the Savings Plans be set to?

Answer 16

Any additional usage will be billed at the On Demand price

Question 17

What two instance attributes are locked for EC2 Savings Plans?

Answer 17

1. Instance family (e.g. M5)
2. Region

Question 18

What three instance attributes are flexible for EC2 Savings Plans?

Answer 18

1. Instance Size (e.g. m5xlarge, m5.2xlarge)
2. OS (e.g. Linux, Windows)
   Tenancy (host, Dedicated, Default)

Question 19

What Purchasing Option has the highest discount in comparison to On-Demand?

Answer 19

Spot Instances (up to 90%)

Question 20

What must you set for Spot Instances?

Answer 20

A max price

Question 21

Why might your Spot Instance be stopped or terminated? And how long is the grace period?

Answer 21

If the max price is less than the current spot price.

The grace period is 2 minutes.

Question 22

What is the most cost efficient Instance purchasing option?

Answer 22

Spot Instances

Question 23

What workloads are Spot Instances useful for? Provide some examples

Answer 23

Useful for workloads that are resilient to failure. Examples are:

Batch jobs
Data analysis
Image processing
Any distributed workloads
Workloads with a flexible start and end time

Question 24

What use cases are NOT suitable for Spot Instances?

Answer 24

Not suitable for critical jobs or databases

Question 25

Which purchasing option provides a physical server with EC2 instance capacity fully dedicated to your use?

Answer 25

Dedicated Hosts

Question 26

What are the two problems that Dedicated Hosts solve

Answer 26

1. Compliance requirements i.e. companies that have strong regulatory or compliance needs 2. Allows companies to use existing server-bound software licenses (per-socket, per-core, per-VM software licenses)

Question 27

What are the purchasing options for dedicated hosts?

Answer 27

On-Demand - Pay per second for active Dedicated Host Reserved - 1 or 3 years ( No Upfront, Partial Upfront, All Upfront)

Question 28

What is the most expensive purchasing option and why?

Answer 28

Dedicated Hosts because you are renting out a physical server that is reserved for your company's use only.

Question 29

How does Dedicated Instances differ from Dedicated Hosts?

Answer 29

1. Instances run on hardware that's dedicated to you and not the entire server.

Question 30

Can you control the instance placement for dedicated instances?

Answer 30

No

Question 31

True or False? For Dedicated instances, you may share hardware with other instances in the same account?

Answer 31

True

Question 32

What is Capacity Reservation?

Answer 32

Where you reserve On-Demand instance capacity in a specific AZ for any duration

Question 33

True or False? You always have access to EC2 Capacity Reservations whenever you need it

Answer 33

True. You can reserve the capacity for any duration

Question 34

True or False? There is a specific time commitment set for EC2 Capacity Reservations.

Answer 34

False. There is no time commitment and you can create/cancel instances within the capacity stated at any time.

Question 35

At what price point are you charged for EC2 Capacity Reservations?

Answer 35

Charged at On-Demand rate whether you run instances or not. No billing discounts.

Question 36

How can you gain billing discounts for Capacity reservations?

Answer 36

Combine with reserved instances and savings plans as capacity reservations are not discounted.

Question 37

What use cases are Capacity Reservations suitable for?

Answer 37

Suitable for short-term, uninterrupted workloads that need to be in a specific AZ.

Question 38

How frequently does the spot price vary and why?

Answer 38

Varies hourly and this is due to capacity

Question 39

What is included in the Spot request when trying to create Spot Instances? List 5

Answer 39

Maximum price Desired number of instances Launch specification When the request is valid from/until Request type (one-time or persistent)

Question 40

When can you cancel Spot Instance requests?

Answer 40

When the request is either open, active or disabled

Question 41

Why must you cancel a spot request before terminating the spot instance?

Answer 41

If the spot request is set to persistent, more spot instances will be created to replace the ones that were terminated based on the desired number of instances set.

Question 42

What are spot fleets?

Answer 42

They are set of spot instances as well as optional on-demand instances. It will try to meet the target capacity based on the price constraints that are set.

Question 43

What are defined by the admin for the launch pools?

Answer 43

The instance type, OS, availability zone

Question 44

True or False? You can have multiple launch pools. (Give a reason)

Answer 44

True. This is so the spot fleet can choose the most appropriate launch pool based on the allocation strategy.

Question 45

When do spot fleets stop launching instances?

Answer 45

Whenever the instance capacity or max price is reached.

Question 46

What are the different spot fleet allocation strategies and their benefits?

Answer 46

LowestPrice: Allocated from the pool with the lowest price (best for cost optimisation and short workloads) Diversified: Distributed across all defined pools (great for availability and long workloads) CapacityOptimised: Pool with the optimal capacity for the number of instances PriceCapacityOptimised (recommended for most workloads): Pools with the highest capacity available, then select the pool with the lowest price.

Question 47

What are the benefits of using a spot fleet over a spot request?

Answer 47

Can get extra savings based on the allocation strategy set