EC2

Question 1

What is EC2

Answer 1

IaaS

Resizable compute capacity in the cloud with a pay-as-you-go billing model

Question 1

What are the four billing models on EC2

Answer 1

- On Demand:
Charged by hour or second
- Reserved:
Reserve at 1 or 3 years with up to 75% discount
- Spot instances
Bid a price you're willing to pay
- Dedicated hosts:
Rent a physical server
Allow using existing server bound software licenses
Can be on demand

Question 2

What pricing model would be best suitable for applications with spiky unpredictable loads?

Answer 2

On demand

Question 3

What pricing model would be best suitable for applications with flexible start and end times, and only feasible at low compute prices loads?

Answer 3

Spot instances

Question 4

What pricing model would you use for software with regulatory requirements that do not support multi-tenancy virtualization?

Answer 4

Dedicated hosts

Question 5

What three types are available with reserved instances?

Answer 5

- Standard:
Up to 75% discount
- Convertible reserved instances:
Up to 54% discount
- Scheduled reserved instances

Question 6

What are some attributes that you can change in a Convertible reserved instance?

Answer 6

Instance family
OS
Tenancy

Question 7

Is termination protection turned on or off by default?

Answer 7

Turned off

Question 8

What is the default action for EBS backed instances when instances are terminated?

Answer 8

Delete the EBS volume, but behavior can be disabled

Question 9

How can you encrypt the EBS root volume of a default AMI?

Answer 9

During AMI creation via console or API, or third party tools (bit locker)

Question 10

What rules does a default security group contain?

Answer 10

Inbound blocked by default

Outbound traffic allowed

Question 11

How much time does it take for changes to Security Groups to be reflected?

Answer 11

Instant

Question 12

T/F Security Groups are stateless

Answer 12

False, security groups are stateful

Question 13

What does it mean for a firewall to be stateful?

Answer 13

It keeps track of what comes in and allows responses to those packages to go back.

Question 14

Can you block specific IPs with security groups?

Answer 14

No

Question 15

How many EC2 instances can be attached to a security group

Answer 15

As many as you want

Question 16

How many Security groups can you assign to an EC2 instance?

Answer 16

Up to 5 at a time (can be expanded up to 16 in extreme situations)

Question 17

In how many AZs are EBS volumes replicated?

Answer 17

1. EBS volumes are only replicated within the AZ

Question 18

What are the main four types of EBS storages?

Answer 18

• General Purpose (gp2)
• Provisioned IOPS (io1)
• Throughput Optimized HDD (st1)
• Cold HDD (sc1)

Question 19

What is an EBS snapshot

Answer 19

An incremental photograph of the disk at a point in time. Stored in S3. Available within AZ.

Question 20

How would you move an EBS volume of AZ? And Region?

Answer 20

Take Snapshot > Take AMI > Launch Instance in other AZ

For moving of region, move AMI first

Question 21

What some attributes that can be changed on the fly on an EBS volume?

Answer 21

Size and storage type

Question 22

How can you encrypt an unencrypted root EBS volume?

Answer 22

Take a snapshot > copy the snapshot with encryption > create AMI from snapshot

Question 23

What is the difference between an AMI Instance Store and an EBS backed volume

Answer 23

Instance store backed instances cannot be stopped, if the underlying host fails, data is deleted. With EBS backed instances they can remain in existence

Question 24

What is an ENI?

Answer 24

Elastic Network Interface

Virtual equivalent of a network card

Question 25

How does Enhanced Networking work?

Answer 25

Uses I/O virtualization (SR-IOV)
Higher I/O performance and lower CPU utilization
Use for good network performance

Question 26

What types of Enhanced Networking are there

Answer 26

• Elastic Network Adapter (ENA):
  Up to 100Gbps for supported instance types
• Inter 822599 Virtual Function (VF):
  Legacy, up to 10Gbps