EC2

Question 1

What is EC2 ?

Answer 1

It is a web service that provides re-sizable compute capacity in the cloud.

Question 2

What are the 4 EC2 Pricing options ?

Answer 2

1) On Demand
2) Reserved
3) Spot
4) Dedicated Hosts

Question 3

What are EC2 On-Demand Instances - Use cases?

Answer 3

1) Users that want the low cost and flexibility of Amazon EC2
2) without any upfront payments.
3) Applications with short term, spikey or unpredictable workloads that cannot be interrupted.
4) Applications being developed or tested for the first time.
5) Learning Environments

Question 4

What are EC2 Reserved Instances - Use Cases?

Answer 4

1) Applications with steady state requirements.
2) Applications with predictable usage.
3) Users can make upfront payments.

Question 5

What are the three reserved instance (RI) types?

Answer 5

1) Standard RI
2) Convertible RI
3) Scheduled RI

Question 6

What is a scheduled RI ?

Answer 6

An EC2 instance that is only available to launch within the time window you reserve.
* It allows you to match your capacity reservation to a predictable recurring schedule that only requires a fraction of a day, month or year.

Question 7

What are Use Cases for EC2 Spot Instances?

Answer 7

1) Applications that have flexible start/finish time.
2) Applications that are only feasible at very low compute prices.
3) Users with an urgent need for large amounts of additional computing capacity.

Question 8

What are the use Cases for dedicated hosts?

Answer 8

1) Useful for customers and licenses who are not eligible to support multi-tenant virtualisation
2) Can be purchased on demand (hourly)
3) can be purchased as a reservation for up to 70% off the on-demand price.

Question 9

Spot Instance Termination - When are you charged?

Answer 9

If a spot instance is terminated by AWS EC2 then you are not charged for the partial hour of usage. If you terminate the instance yourself then you will be charged for the complete hour in which the instance ran.

Question 10

What is EC2 Termination Protection?

Answer 10

Prevents the deletion of an instance, it’s turned off by default.

Question 11

Describe EC2 On Demand Instances:

Answer 11

Allows to pay a fixed rate by the hour, with no commitment.
Recommended for:
Applications with unpredictable workloads
Applications that can’t be interrupted

Question 12

Describe EC2 Reserved Instances.

Answer 12

Provides a capacity reservation, with significant discount.
Contract terms are 1 or 3 years.
- Applications with Predictable workloads.
There are 3 types:
- Standard
- Convertible
- Scheduled

Question 13

What are the 3 types of EC2 Reserved Instances:

Answer 13

Standard:
 - 75% of discount from On Demand price
Convertible:
 - You may convert one instance to another.
Scheduled:
- Works at specific time intervals.

Question 14

Describe EC2 Spot Instances

Answer 14

Unused instances on which you bid on.
AWS will assign them to you if your target price is above the spot price.
Workload will run as long as the price is below.
Ideal for workloads that can be interrupted.

Question 15

Describe EC2 Dedicated host instances

Answer 15

Used for regulatory applications.

Can be purchased on demand.

Question 16

Can you encrypt the root device volume?

Answer 16

Yes, from the beginning or at a later time

Question 17

What is the default action for the volumes when you terminate an EC2 instance?

Answer 17

To delete the root volume, and keep the rest.

Question 18

What’s the difference between Security Group rules and NACLs (network access controls LIsts)?

Answer 18

Security groups rules are stateful: once you allow inbound traffic to a port, outbound traffic is allowed.
NACLs rules are state-less: you have to permit inbound and outbound traffic rules.

Question 19

How does traffic behaves on security Groups by default?

Answer 19

All traffic is blocked, you must create “allow” rules to allow specific traffic.

Question 20

What types of Storage are available for EC2 Instances?

Answer 20

EBC and Instance Store

Question 21

How is sometimes called Instance Store?

Answer 21

Ephemeral Storage, since it is not persistent.

Question 22

What is the difference between EBS and Instance Store?

Answer 22

If an instance store backed AMI fails at the Hypervisor, data will be lost.
None will lose data if rebooted.
EBS can be stopped, Instance Store can’t.
You can’t keep an Instance Store volume.
Instance Store volumes can’t be seen in Volumes.

Question 23

What is ENI?

Answer 23

Elastic Network Interface:

• provides a primary private IPv4 address
• One or more private IPv4 address
• One elastic IPv4 per private address
• One or more IPv6 address
• One or more security groups
• A MAC Address
• A source/destination check flag
• A description.

Question 24

What is Enhanced Networking?

Answer 24

It’s a method to provide higher network performance to your EC2 instance, only available to some instance types.

Question 25

What does Enhanced Networking SR-IOV stands for?

Answer 25

Single root I/O Virtualization

Question 26

What options of Enhanced Networking exist?

Answer 26

Elastic Network Adapter (ENA) and Virtual Function (VF)

Question 27

What is the supported speed of ENA?

Answer 27

100 Gbps

Question 28

What is EFA and what is it’s purpose?

Answer 28

Elastic Fabric Adapter,enhance HPC and ML workloads.,

• Low latency
• bypasses OS
• Only Linux support

Question 29

What are the uses of ENI vs ENA vs EFA?

Answer 29

ENI - additional network interfaces.
ENA - High performance Network interface
EFA - HPC or ML workloads.