Advanced EC2

Question 1

EC2 User Data

Answer 1

anything in the user Data is executed by the instance OS

but Only on Lunch

EC2 doesn’t interpret the OS needs to understand the User data

Question 2

Adress for EC2 User data

Answer 2

http://169.254.169.254/Latest/user-data

Question 3

CFN-INIT

Answer 3

helper script - installed on EC2 OS

simple configuration management system

procedural(User Data) vs Desired State(cfn-init)

it can control what packages gets installed, Groups, user, files commands and services

Question 4

What makes CFN-INIT so powerful ?

Answer 4

can be used to rerun scripts through metadata and cloud formation making it more reactive than if you were to bootstrap through just EC2 user data

and it works with stack updates

Question 5

creationPolicy and signals

Answer 5

by default cloud formation doesn’t know if the instance bootstrapping data fails

creating a creationPolicy with a resouceSignal enables cloud formation to wait for a signal from the instance itself before it moves to create complete

Question 6

EC2 Instance Roles

Answer 6

How EC2 instances get permissions

Question 7

How is an instance role attached to an EC2 instance ?

Answer 7

when you create an instance role in the UI a Instance Profile gets created of the same name it’s that profile that gets attached to an instance then temp credentials are delivered via meta-data

Question 8

System Manager Parameter Store

Answer 8

storage for configuration and secrets

string, stringlist and secureString

Hierarchies and versioning

store plaintext and cipher (through KMS permission need to be added)

Public parameters - latest AMIs per region

Question 9

What is CloudWatch used for ?

Answer 9

Metrics

Question 10

what is Cloud Watch Logs user for ?

Answer 10

logging

Question 11

If you want to captured data inside an instance which service would you user cloudWatch or CloudWatch logs ?

Answer 11

CloudWatch Logs but neither can natively capture data inside an instance you have to install CloudWatch agent on an EC2 instance to do that

Question 12

Placement Groups : Cluster

Answer 12

Pack instance close together

Question 13

Placement Group: Spread

Answer 13

Keep instances separated

Question 14

Placement Groups: Partition

Answer 14

groups of instance spread apart

Question 15

What can impact the performance of an Clust Placement groups ?

Answer 15

can span VPC peers - but impacts performance

us the same type of instance (not mandatory)

Launch at the same time(not mandatory … very recommended)

Question 16

Draw backs to a cluster placement group?

Answer 16

can’t span AZs - one AZ only locked when launching first instance

requires a support instance type

Question 17

What are the benefits of a Cluster placement group ?

Answer 17

10GBps p/ stream vs 5gbps normally

all members have a direct connection to each other

same Rack and sometime same host

Question 18

Spread placement group benefits

Answer 18

provides infrastructure Isolation

each instance runs from a different rack

each rack has it’s own networking and power source

Question 19

Drawback of a spread placement group ?

Answer 19

7 instances per Az(hard limit )

Not supported for dedicated instances or host

Question 20

Cluster placement Group use cases

Answer 20

high performance, fast speed and low latency

Question 21

Spread Placement Group

Answer 21

small number of critical instances that need to be kept separate from each other

Question 22

Partition Placement Groups Drawbacks

Answer 22

7 partitions per Az

Question 23

Use case for a Partition Placement Groups ?

Answer 23

contain the impact of a failure to a part of an application

Question 24

Benefits of a partition placement Group ?

Answer 24

greate for topology(application with it’s own networks or nodes) aware applications like HFFS,HBase and Cassandra

Question 25

Dedicated Hosts

Answer 25

Host dedicated to you, you pay for the host no instance charge

Question 26

Drawback of dedicated host

Answer 26

older version of dedicated host the instance family has to has to be specified when making host new host instance families don’t have to be specified

Question 27

Payment types for Decificate Host ?

Answer 27

on-demand and reserved options (1yr or 3 yrs )

Question 28

Benefits of dedicated Host

Answer 28

Host hardware has physical sockets and cores

Question 29

EBS Optimized

Answer 29

dedicated bandwidth for storage networking - separate from data networking.

generally enabled and comes built in for all modern instances

older instances enabling cost extra