EC2 Basics

Question 1

What is EC2?

Answer 1

Elastic Compute Cloud

Question 2

What is EBS?

Answer 2

Elastic Block Store - Like an external HD

Its block storage for Amazon EC2 compute instances - it is similar to hard drives attached to your computers or laptops, but in a virtualized environment.

Question 3

What is ELB? What does it use for?

Answer 3

Elastic Load Balancer - Distributing load across machines

Question 4

What is ASG?

Answer 4

Scaling the services using an Auto-Scaling Group

Question 5

What is EFS

Answer 5

Elastic File System

Provides scalable network file storage for Amazon EC2 cloud computing service users.

Question 6

What is the different between EFS and EBS?

Answer 6

AMAZON EBSAMAZON EFS Accessible only via the given EC2 Machine
File System interface
Block Storage
Hardly scalable
Faster than S3 and EFSAccessible via several EC2 machines and AWS services
Web and file system interface
Object storage
Scalable
Faster than S3, slower than EBS Is meant to be EC2 driveGood for applications and shareable workloads

Question 7

What is bootstrapping?

How many time it will run?

Answer 7

bootstrapping means launching commands when a machine starts

Can only run once

Question 8

What does EC2 user data is used to automate at boot tasks?

(us, da?!)

Answer 8

EC2 user data is used to automate boot tasks such as:

• Installing updates
• Installing software
• Downloading common files from the internet
• Anything you can think of

Question 9

Who can run the EC2 User Data Script?

Answer 9

Only the root user

Question 10

What does the naming convention means?

m5.2xlarge

Answer 10

• m: instance class
• 5: generation (AWS improves them over time)
• 2xlarge: size within the instance class

Question 11

What does Security groups act like in EC2?

Answer 11

Security groups are acting as a “firewall” on EC2 instances

Question 12

What Security Groups adjust?

(AA IO)

Answer 12

1. Access to Ports
2. Authorised IP ranges – IPv4 and IPv6
3. Control of inbound network (from other to the instance)
4. Control of outbound network (from the instance to other)

Question 13

To how many EC2 you can attached a security group?

Answer 13

Can be attached to multiple instances

Question 14

Where is the security group “lives”?

Answer 14

“Lives” “outside” the EC2 – if traffic is blocked the EC2 instance won’t see it

Question 15

I security group, What to remember about SSH?

Answer 15

It’s good to maintain one separate security group for SSH access

Question 16

When an application getting “time out, Where is the problam?

Answer 16

If your application is not accessible (time out), then it’s a security group issue

Question 17

Where it the problem If your application gives a “connection refused“ error?

Answer 17

f your application gives a “connection refused“ error, then it’s an application error or it’s not launched

Question 18

In security groups, What is the default for inbound and outbound?

Answer 18

All inbound traffic is blocked by default

All outbound traffic is authorized by default

Question 19

What are EC2 Instances Purchasing Options?

(OD R SP SI DH DI CR)

Answer 19

• On-Demand Instances – short workload, predictable pricing, pay by second
• Reserved (1 & 3 years)
• Reserved Instances – long workloads
• Convertible Reserved Instances – long workloads with flexible instances
• Savings Plans (1 & 3 years) –commitment to an amount of usage, long workload
• Spot Instances – short workloads, cheap, can lose instances (less reliable)
• Dedicated Hosts – book an entire physical server, control instance placement
• Dedicated Instances – no other customers will share your hardware
• Capacity Reservations – reserve capacity in a specific AZ for any duration

Question 20

When EC2 On Demand is good?

Answer 20

Recommended for short-term and un-interrupted workloads, where
you can’t predict how the application will behave