AWS EC2 - part 2

Question 1

What is EC2 user data

Answer 1

possible to bootstrap instances using an EC2 user data script

Question 2

what is bootstrapping?

Answer 2

launching commands when a machine starts

Question 3

How often is EC2 user data script run?

Answer 3

Only once, when machine starts

Question 4

What are some examples of how UC2 user data is used to automate boot tasks?

Answer 4

Installing Updates
Installing Software
Downloading common files from the internet
Anything you can think of

Question 5

What user does EC2 user data script run under?

Answer 5

root/admin

Question 6

What can you configure for an EC2 instance?

Answer 6

CPU
Memory
Storage
Network performance
EBS bandwidth

Question 7

What does the EC2 instance naming convention?

Answer 7

m:instance class, 5:generation, 2xlarge: size of instance class

Question 8

What is a Security Group?

Answer 8

A firewall on our EC2 instance.
Regulate access to ports
authorized IP ranges
control inbond netowrk
control outbound network
type: protocol, port range, source

Question 9

How many instances can a security group to be associated?

Answer 9

many

Question 10

If app gets a timeout (not accessible) what is the likely cause of the errror?

Answer 10

Security group issue

Question 11

If your app give “connection refused” error, what is the likely cause?

Answer 11

An application error or it is not launched

Question 12

What is port 22 for?

Answer 12

SSH

Question 13

What is port 21 for?

Answer 13

FTP

Question 14

What is port 22 for?

Answer 14

Secure File Transfer Protocol (upload files using SSH)

Question 15

what is port 80 and 443 for?

Answer 15

http/https

Question 16

What is port 3389 for?

Answer 16

RDP for windows instances

Question 17

What do you use for SSH for?

Answer 17

To remote into servers (mac, linux, windows >= 10)

Question 18

What is EC2 instance connect?

Answer 18

Remote into to any OS

Question 19

What is the command line to SSH to an instance?

Answer 19

ssh usersname@IPaddress, example ssh ec2-users@3.250.26.200

Question 20

How to use EC2 .pem file?

Answer 20

ssh -i <*.pem> ec2-users@<publicip> in directory with pem file (after chmod 0400 pem file)</publicip>

Question 21

How to you provide aws permissions to an EC2 instance?

Answer 21

Attach an IAM role (in the EC2 instance UI for example)

Question 22

How are you charged for an on-demand instance?

Answer 22

By the second

Question 23

How are you charged for reserved instances?

Answer 23

Up to 72% discount, pay by the year or 3 years, pay no upfront, partial upfront, all upfront

Question 24

What is EC2 spot instance

Answer 24

can get 90% discount, instance you can lose at any time if your max price is less than spot price

Question 25

What is EC2 dedicated host?

Answer 25

A physical server dedicated, address compliance or use existing licenses

Question 26

What is ElasticIP

Answer 26

Public IP that doesn’t change when EC2 stops and starts. (Can only have 5 per AWS account) Should not use, use DNS instead

Question 26

What is ElasticIP

Answer 26

Public IP that doesn’t change when EC2 stops and starts. (Can only have 5 per AWS account) Should not use, use DNS instead

Question 27

What is a placement group?

Answer 27

can control EC2 placement strategy, (cluster(availability zone), spread, partition

Question 28

What is cluster placement group?

Answer 28

Same hardward/rack and availabiliy zone? pro, great network, con: single point of failure. use case(big data job, or needs high network throughput)

Question 29

What is spread placement group?

Answer 29

EC2 instances spread across machine and availability zones. Pro: availability. Con: limit to 7 instances. Use case: max high availability

Question 30

What is partition placement group?

Answer 30

Instances spread across multiple availability zones. Each partition represents a rack. Safe from rack failure. Up to 100s of instances. Use case: Big data, Kafka, Cassandra…