EC2 - Elastic Compute Cloud

Question 1

What OS you can not use to SSH into your instance?

Answer 1

• Windows < 10, you can use any other OS including - - - Windows >= 10

Question 2

In what OS can you use Putty?

Answer 2

any Windows version

Question 3

In what OS you can use Instance Connect?

Answer 3

All, don’t get confused with AMI

Question 4

What is Instance Connect used for?

Answer 4

Connecting to your instance within your browser

Question 5

Do you need your key file for Instance Connect?

Answer 5

No, your key file is only needed for SSH and/or Putty

Question 6

Does Instance Connect need port 22 open?

Answer 6

Yes, same as SSH and/or Putty

Question 7

Does Instance Connect work with any AMI?

Answer 7

Works only out-of-the-box with Amazon Linux 2

Question 8

What can you use to bootstrap your instance?

Answer 8

EC2 User Data script

Question 9

How many times does EC2 User Data run?

Answer 9

only once at the first start

Question 10

What is used #!/bin/bash for?

Answer 10

It is the beginning of EC2 user data script

Question 11

Which are the Instance Launch Types?

Answer 11

• On Demand Instances
• Reserved Instances (Regular, Convertible, Scheduled)
• Spot Instances
• Dedicated Instances
• Dedicated Hosts

Question 12

What is the commitment term of On demand Instances

Answer 12

no long term

Question 13

What is the commitment term of Reserved Instances

Answer 13

long term, 1 to 3 years.

Question 14

What is the cost of Convertible Reserved Instances compared to On Demand Instances and Regular Reserved Instances?

Answer 14

Cheaper than On-Demand but more expensive than Regular Reserved

Question 15

What is a Convertible Reserved Instance?

Answer 15

A reserved instance that you can change its instance type

Question 16

What is a Scheduled Reserved Instance?

Answer 16

A reserved instance that you can launch within time window you reserve

Question 17

What is the cost of Spot Instances compared to the other Instance Launch types?

Answer 17

the most cost-efficient

Question 18

What is a Spot Instance?

Answer 18

An instance that you can “lose” at any point of time if

your max price is < current spot price

Question 19

What is a Dedicated Host?

Answer 19

It is a physical dedicated EC2 server for your use

Question 20

What is the cost of Dedicated Hosts?

Answer 20

The most expensive

Question 21

What is the cost of On demand instances

Answer 21

the highest ignoring Dedicated Hosts but no upfront payment, pay for what you use

Question 22

What is recommended for On demand instances

Answer 22

for short, predictable workloads

Question 23

What is the cost of Reserved Instances compared to On Demand Instances?

Answer 23

< On-demand and you pay upfront for what you use

Question 24

What is recommended for Reserved Instances?

Answer 24

long workloads, databases

Question 25

What is recommended for Spot Instances?

Answer 25

for Batch jobs, data analysis, image processing, not for critical jobs

Question 26

What is the period that a Dedicated Hosts is allocated for your account?

Answer 26

Allocated for your account for 3 years.

Question 27

Mention 2 things that Dedicated Hosts allow you to do

Answer 27

- Full control of instance placement. | - Visibility into the underlying sockets, physical cores of the hardware

Question 28

What is specially useful for Dedicated Hosts?

Answer 28

For software that have complicated licensing model (BYOL - Bring Your Own License) or for companies that have strong regulatory or compliance needs

Question 29

What is a Dedicated Instance?

Answer 29

Instances running on hardware that's dedicated to your account

Question 30

Which are the 7 main EC2 instance types?

Answer 30

``` R (RAM) - in memory caches C (CPU) - compute / db M (Medium) - general / web app I (I/O) - good local I/O G (GPU) - video rendering / machine learning T2/T3 (Burstable Instances) T2/T3 unlimited ```

Question 31

What is a burstable instance (T2/T3)

Answer 31

if machine needs to process something unexpected (a spike in load for example), it can burst, and CPU can be VERY good.

Question 32

What are burst credits?

Answer 32

It is what burstable instances uses when bursting and it is accumulated. If all credits are gone the CPU becomes BAD

Question 33

What to do if you are always running low on burst credit?

Answer 33

you need to move to a different kind of non-burstable instance

Question 34

What is a burstable instance (T2/T3 UNLIMITED)

Answer 34

It is a burstable instance but you don't lose the burst by paying extra money if you go over your burst credit

Question 35

What is an AMI?

Answer 35

Amazon Machine Image is used to create out instances from it and can be built on Linux or Windows machines

Question 36

Are AMIs region-scoped?

Answer 36

Yes

Question 37

What are the advantages of AMIs?

Answer 37

- Faster boot time. - Pre-installed packages. - Active Directory integration out of the box. - Using someone else's optimised AMIs for different purposes

Question 38

Where can I find an AMI?

Answer 38

On the Amazon Marketplace

Question 39

Would you need to pay for other people's AMI?

Answer 39

Yes, by the hour

Question 40

Where are AMIs placed?

Answer 40

in S3, but they are not visible on the console

Question 41

How are AMIs by default? private or public?

Answer 41

private, locked for account / region

Question 42

What is an ENI?

Answer 42

Elastic Network Interface is a logical component that represents a virtual network card

Question 43

Name the attributes of an ENI:

Answer 43

* 1 primary private IPv4, one or more secondary IPv4 * One Elastic IP (IPv4) per private IPv4 * One Public IPv4 * One or more security groups * A MAC address

Question 44

Can you re use an ENI?

Answer 44

You can create ENI independently and attach them on the fly (move them) on EC2 instances for failover

Question 45

Are ENIs multi AZ?

Answer 45

They are bound to a specific AZ

Question 46

How are you billed in EC2?

Answer 46

by the second, with a minimum of 60 seconds

Question 47

When you do not pay for the instance?

Answer 47

if it is stopped

Question 48

EC2 instances prices (per hour) varies based on:

Answer 48

* Region * Instance Type * Instance Launch Type * Linux vs Windows vs Private OS (RHEL, SLES, Windows SQL

Question 49

Suppose t2.small in US-EAST-1 (VIRGINIA), cost $0.023 per Hour. If used for 6 seconds, how much is it?

Answer 49

6 seconds, it costs $0.023/60 = $0.000383 (minimum of 60 seconds)

Question 50

Suppose t2.small in US-EAST-1 (VIRGINIA), cost $0.023 per Hour. If used for 60 seconds, how much is it?

Answer 50

60 seconds, it costs $0.023/60 = $0.000383 (minimum of 60 seconds)

Question 51

Suppose t2.small in US-EAST-1 (VIRGINIA), cost $0.023 per Hour. If used for 30 minutes, how much is it?

Answer 51

30 minutes, it costs $0.023/2 = $0.0115