EC2

Question 1

What does EC2 stand for?

Answer 1

Elastic compute Cloud

Question 2

What is the EC2 User Data Script used for?

Answer 2

To automate boot tasks such as installing updates/software, downloading files etc.

Question 3

What are the use cases for General Purpose EC2 Instance Types?

Answer 3

Web servers, Code repositories etc.

Question 4

What are 6 example use cases for Compute Optimized EC2 Instances?

Answer 4

• Batch Processing Workloads
• Media Transcoding
• High Performance Web Servers
• High Performance Computing (HPC)
• Scientific Modeling and Machine Learning
• Dedicated Gaming Servers

Question 5

What are 4 example use cases for Memory Optimized EC2 Instances?

Answer 5

• High Performance databases
• Distributed web scale cache stores
• In-memory databases optimized for BI
• Apps performing real-time processing of big unstructured data

Question 6

What are 5 use case examples for Storage Optimized EC2 Instances?

Answer 6

• High frequency online transaction processing systems (OLTP)
• Relational and non relational databases
• Cache for in-memory databases (Redis)
• Data Warehousing applications
• Distributed File System

Question 7

What is a Security Group?

Answer 7

It is like a Firewall

Question 8

What 4 things do Security Groups Regulate?

Answer 8

• Access to Ports
• Authorized IP ranges
• Control of inbound network
• Control of outbound network

Question 9

Can a Security Group be attached to multiple EC2 instances?

Answer 9

Yes, and an instance can have multiple security groups

Question 10

Are Security Groups Global?

Answer 10

No, they are tied to a specific region/VPC combination.

Question 11

If my application is showing a timeout when I try to connect, what is the likely cause?

Answer 11

A security group misconfiguration

Question 12

If my application gives a connection refused error, what is the likely cause?

Answer 12

An app error or app failed to launch. The security group config is fine

Question 13

What are the default inbound/outbound security group settings?

Answer 13

• Inbound traffic is blocked

- Outbound traffic is authorized

Question 14

What is the SSH port?

Answer 14

22

Question 15

What is the FTP pport?

Answer 15

21

Question 16

What is the SFTP port?

Answer 16

22

Question 17

What is the HTTP port?

Answer 17

80

Question 18

What is the HTTPS port?

Answer 18

443

Question 19

Whats is the RDP port?

Answer 19

3389

Question 20

What are the 4 EC2 Instance purchasing options?

Answer 20

• On-Demand instances
• Reserved Instances
• Spot Instances
• Dedicated Hosts

Question 21

What are 4 features of On-Demand Instances?

Answer 21

• Pay for what you use
• Highest cost but no upfront payment
• No long term commitment
• Recommended for short term and un-interrupted workloads

Question 22

What are the 5 features of Reserved Instances?

Answer 22

• Up to 75% discount compared to on-demand
• Reservation periods of 1 or 3 years
• Pay zero upfront, partial or full
• Reserve a specific instnace type
• Recommended for steady state apps like databases

Question 23

What are the 2 types of Reserved Instances?

Answer 23

• Convertible

- Scheduled

Question 24

What are 5 features of Spot Instances?

Answer 24

• Up to 90% discount compared to on-demand
• Can lose instances anytime if your bid price gets lower than the spot price
• Most cost-efficient instances
• Useful for workloads that are resilient to failure
• Not suitable for critical jobs or databases

Question 25

What are 5 examples of apps that are resilient to failure?

Answer 25

- Batch jobs - Data Analysis - Image Processing - Distributed workloads - Workloads with flexible start/end time

Question 26

What are the 5 features of Dedicated Hosts?

Answer 26

- Helps address compliance requirements and reduce costs by using existing software licenses - Allocated to your account for 3 years - More expensive - Useful for software that has a complicated licensing model (BYOL) - Suitable for string compliance or regulatory needs

Question 27

What is the difference between Dedicated Host and Dedicated Instance?

Answer 27

A Dedicated instance does not provide access to the underlying hardware for the dedicated resources

Question 28

What is a Spot Block?

Answer 28

It allows you to block a spot instance for a specified time frame 1-6 hours

Question 29

How many Elastic IPs can you have in your account?

Answer 29

5

Question 30

What should you do instead of using ElasticIPs?

Answer 30

- Use random public IPs and register a DNS name to it | - Use Load Balancer instead of public IP

Question 31

What are the 3 strategies available for Placement Groups?

Answer 31

- Cluster - Spread - Partition

Question 32

What does the Cluster Strategy for placement groups do?

Answer 32

Clusters instances into a low latency group in a single partition in a single AZ

Question 33

What does the Spread Strategy for placement groups do?

Answer 33

Spreads instances across underlying hardware, with a max of 7 instances per group per AZ

Question 34

What does the Partition Strategy for placement groups do?

Answer 34

Spreads instances across many different partitions within an AZ

Question 35

What does ENI stand for?

Answer 35

Elastic Network Interfaces

Question 36

What is an ENI?

Answer 36

A logical component in a VPC that represents a virtual network card

Question 37

What are the 5 most important attributes an ENI can have?

Answer 37

- Primary private IPv4 - One Elastic IP - One Public IPv4 - One or more Security Groups - A MAC address

Question 38

Is an ENI tied to a specific EC2 instance?

Answer 38

No, they can be created independently and moved from one instance to another

Question 39

Is an ENI global?

Answer 39

No, they are AZ specific

Question 40

What is EC2 Hibernate?

Answer 40

It is a new feature that preserves the in-memory state in the event an instance is stopped.

Question 41

What are 3 use cases for Hibernate?

Answer 41

- Long running processes - Saving RAM state - Services that take time to initialize

Question 42

What is EC2 Nitro?

Answer 42

The underlying platform for the next generation of EC2 instances

Question 43

What are the 2 advantages of Nitro?

Answer 43

- Better Networking Options | - Higher Speed EBS, for up to 64,000 IOPS

Question 44

Can I change the default number of cores and threads?

Answer 44

Yes, you can optimize vCPU to specify that you want 2 cores instead of 4, 1 thread per core instead of 2 at instance launch time