EC2

Question 1

What is a role?

Answer 1

An entity designed to be assumed. It provides temporary access using temp credentials

Question 2

What do roles enable in an account?

Answer 2

They enable cross account access

Question 3

Are roles regional?

Answer 3

No they are global

Question 4

Why would you want to use roles in EC2?

Answer 4

Avoids hard coding credentials

Question 5

Can you attach/detach roles on a running EC2 instance?

Answer 5

Yes you can

Question 6

What are Security Groups?

Answer 6

Virtual Firewalls

Question 7

By default what settings does a Security Group have?

Answer 7

Everything inbound by default is blocked. All outbound traffic is allowed

Question 8

What are bootstrap scripts?

Answer 8

Scripts that run on instance first startup

Question 9

What permissions do bootstrap scripts have?

Answer 9

Has root access

Question 10

Why use bootstrap scripts?

Answer 10

Enables automation of installing applications in EC2

Question 11

How many instances can be in a Security Group?

Answer 11

Unlimited

Question 12

How many Security Groups can an instance attach?

Answer 12

5

Question 13

What is EC2 metadata?

Answer 13

Data about ec2 instance such as ip addresses, hostname, SG’s

Question 14

What is the url for EC2 metadata?

Answer 14

169.254.169.254/latest/meta-data

Question 15

What is EC2 user-data?

Answer 15

The bootstrap scripts

Question 16

Can you access metadata via userdata?

Answer 16

Yes

Question 17

What are the 3 types of network adapters for ec2?

Answer 17

1. ENI - elastic network interface
2. EN - enhanced networking
3. EFA - elastic fabric adapter

Question 18

What are use cases for ENI?

Answer 18

everyday networking, dual homed instances, interact with VPC or different networks

Question 19

What are use cases for EN?

Answer 19

High performance I/O, high bandwidth, lower latency, single root virtualization. 10-100Gbps

Question 20

What are the 2 types of EN? Which should you always choose?

Answer 20

1. ENA - elastic network adapter
2. VFI - virtual function
   always choose ENA

Question 21

What are use cases for EFA?

Answer 21

HPC, machine learning, OS bypass

Question 22

What are the 3 types of placement groups?

Answer 22

1. Clustered
2. Partitioned
3. Spread

Question 23

What is Clustered Placement group?

Answer 23

Instances are grouped together into the same AZ

Question 24

Why use Clustered placement group?

Answer 24

Low latency, network throughput, HPC

Question 25

What is Partitioned Placement group?

Answer 25

Multiple Instances are partitioned where partitions are on different racks/hardware

Question 26

What is Spread Placement group?

Answer 26

Individual Instances are placed on their own distinct hardware

Question 27

Why use a Spread Placement group?

Answer 27

Keep small # critical instances separate from another

Question 28

Why use a Partitioned Placement group?

Answer 28

Isolate impact of power/network failures. For distributed systems like HDFS, Cassandra

Question 29

What Placement group can span multiple Az's and what can't?

Answer 29

Clustered cannot span multiple AZ's | Partitioned and Spread can span

Question 30

Can you merge placement groups?

Answer 30

No you can't merge

Question 31

Can you remove/add existing instances into a placement group? The instance has to be in what state?

Answer 31

Yes, but the instance must be stopped

Question 32

When should you use EC2 dedicated hosting?

Answer 32

When you need dedicated physical hardware due to compliance or licensing

Question 33

When should you not use spot instances?

Answer 33

1. Critical workloads 2. Databases 3. Persistent workloads

Question 34

What are some use cases for spot instances?

Answer 34

1. CI/CD 2. containerized workloads 3. high performance computing 4. Big data analytics

Question 35

How much can you save with spot instances?

Answer 35

up to 90% savings

Question 36

How do spot instances work?

Answer 36

You set a max spot price, and spot instances will be provisioned if it is below this price

Question 37

What is a Spot Block?

Answer 37

Stops spot instances from being terminated if the price goes above your max spot price. Can be set for 1-6 hours.

Question 38

What is a spot request? What are the 2 types?

Answer 38

Defines the spot price max, # instances you want, launch template, valid time range, request type. 1. Onetime spot request 2. Persistent Spot request (keeps provisioning instances until request is met if open/price)

Question 39

What do you need to do to terminate instances in a persistent spot request?

Answer 39

You need to cancel the spot request first to prevent it from reprovisioning instances, then terminate instances