EC2 101

Question 1

What does EC2 stand for?

Answer 1

Elastic Compute Cloud

Question 2

At a high level, what does EC2 provide?

Answer 2

EC2 is a web service that provides resizeable compute capacity in the cloud

Question 3

Why is EC2 useful?

Answer 3

• EC2 reduces the time required to obtain & boot new server instances to minutes.
• This allows you to quickly scale capacity (both up and down) as computing requirements change

Question 4

What are the 4 core principles behind the EC2 pricing model?

Answer 4

• Pay as you go
• Pay for what you use
• Pay less as you use more
• Pay even less as you reserve capacity

Question 5

What are the 4 EC2 Pricing Models?

Answer 5

• On Demand
• Reserved
• Spot
• Dedicated Hosts

Question 6

How does On Demand Pricing for EC2 instances work?

Answer 6

Pay a fixed rate by the hour (or second) with no time commitment

Question 7

At a high level, how does Reserved Pricing for EC2 instances work?

Answer 7

Reserved Pricing provides you with a capacity reservation, at a significant discount on the hourly rate.

Question 8

How long is the contract on a Reserved Instance in EC2?

Answer 8

Can be 1 year or 3 years

Question 9

A user is developing and testing an application using EC2 for the first time. Which EC2 pricing model best suits their use case?

Answer 9

On Demand Pricing

Question 10

A user’s application requires a reserved capacity, and they are able to make upfront payments to save money. Which pricing model makes the most sense in this scenario?

Answer 10

Reserved Pricing

Question 11

What are the three types of Reserved Instances Classes?

Answer 11

• Standard Reserved Instances
• Convertible Reserved Instances
• Scheduled Reserved Instances

Question 12

What is the key difference between a Standard Reserved Instance and a Convertible Reserved Instance?

Answer 12

• A Convertible Reserved Instance is more flexible on the fly.
• In general, you can change the attributes of a convertible reserved instance as long as the change results in a reserved instance class of equal or lesser value.

Question 13

What is the best way to purchase compute capacity reservations that do not run continuously, but do recur on a regular schedule (daily, weekly, monthly)

Answer 13

Use Scheduled Reserved Instances

(Source)

Question 14

How do EC2 Spot Instances work?

Answer 14

When EC2 has unusued capacity, Amazon drops the price of instances, so you can bid whatever price you want for instance capacity (“Free market”)

Question 15

An application has an urgent computing need that calls for large amounts of additional compute capacity. Which EC2 pricing model makes the most sense for this use case?

Answer 15

Spot Instances

(On-Demand might also work here but will be costlier. Spot is better since we need additional compute. Spot should not handle 100% of your compute capacity)

Question 16

If a Spot Instance is terminated by Amazon EC2 after you have used it for 2.5 hours, how much are you charged for it?

Answer 16

2 hours at whatever price you bid for it.

If a Spot instance is terminated by EC2 (called a Spot Instance Interruption), you are not charged for the partial hour in which it ran.

Question 17

If you terminate a spot instance after using it for 2.5 hours, how much do you pay for using the instance?

Answer 17

3 hours at whatever price you bid for it.

If you terminate a spot instance, you are charged for any hour in which the instance ran.

Question 18

What is a Dedicated Host?

Answer 18

A Dedicated Host is a physical EC2 server dedicated for your use.

Question 19

A user wants to use an existing server-bound software license to reduce compute costs. Which pricing model makes the most sense for this use case?

Answer 19

Dedicated Hosts

Question 20

What is the pricing model for Dedicated Hosts?

Answer 20

• Dedicated Hosts can be purchased on-demand (hourly)
• Dedicated Hosts can be purchased as a reservation for up to 70% off the on-demand price.

Question 21

What is Termination Protection for EC2 instances?

Answer 21

• Termination Protection helps prevent you from accidentally terminating your instances

Question 22

On an EBS-backed EC2 instance, assuming default settings, what happens to the root EBS volume once the instance is terminated?

Answer 22

The root EBS volume is deleted

Question 23

An application has short-term, spiky, or unpredictable workloads that cannot be interrupted. Which EC2 pricing model makes the most sense for this use case?

Answer 23

On-Demand Pricing

(Spot would not work since it can be interrupted)

Question 24

A user wants the low cost and flexibility of EC2 but does not want to make a long-term commitment or an up-front payment. Which EC2 pricing model makes the most sense for this use case?

Answer 24

On-Demand Pricing

(Reserved is a long-term commitment;
Spot is not as much flexibility)

Question 25

An application has steady-state and predictable usage. Which EC2 pricing model makes the most sense for this use case?

Answer 25

Reserved Instances

Question 26

A users application requires a reserved capacity. What is the best pricing model for this use case?

Answer 26

Reserved EC2 Pricing

Question 27

A user’s application has flexible start and end times. Which pricing model makes the most sense in this scenario?

Answer 27

Spot Instance Pricing

Question 28

A user’s application is only feasible at low compute prices. Which pricing model makes the most sense for this use case?

Answer 28

Spot Instances

Question 29

A User’s license does not support multi-tenancy of cloud deployments. Which EC2 pricing model makes the most sense for this use case?

Answer 29

Dedicated Hosts

Question 30

A User’s regulatory requirements do not support multi-tenant virtualization. Which pricing model makes the most sense for this use case?

Answer 30

Dedicated Hosts

Question 31

Is Termination Protection for EC2 instances enabled by default?

Answer 31

No