Fundamentals of AWS (Part 1) Flashcards

1
Q

If you want control over the EC2 Instance placement strategy? This is called what?

A

Placement Groups

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2
Q

What’s the difference between IAM Users, Groups and Roles?

A

Users: Usually a physical person.
Groups: Functions (admins, devops) Teams (engineering, design…) Contains users!
Roles: Internal usage within AWS resources.

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3
Q

How many roles per application?

A

One

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4
Q

What port does AWS use for SSH?

A

Port 22

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5
Q

Security Groups are the fundamental of what type of security in AWS?

A

Network Security

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6
Q

How are security groups used for EC2?

A

They control how traffic is allowed into or out. They act as a firewall.

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7
Q

What all do security groups regulate?

A
  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
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8
Q

Can a security group be attached to multiple instances or only 1?

A

Multiple Instances

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9
Q

T / F: Security Groups are locked down to a region / VPC combination

A

T

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10
Q

If you experience a time out when trying to access your application. This it most likely due to what?

A

Security Group Issue

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11
Q

If you recieve a “connection refused” error, then what’s likely going on?

A

It’s an application error or it’s not launched.

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12
Q

T/F: For security Groups, all inbound traffic is blocked by default?

A

True

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13
Q

T/F: For security Groups, all outbound traffic is blocked by default?

A

False. It’s authorized

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14
Q

Public IP means the machine can be identified where?

A

On the internet

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15
Q

Private IP means the machine can be identified where?

A

Only on a private network.

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16
Q

How to private IP machines connect to the internet?

A

Using an internet gateway (a proxy)

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17
Q

T / F: When you stop and start an EC2 instance, it’s public IP remains constant?

A

False - It can change its public IP

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18
Q

This will provide you a fixed public IP for your instance

A

Elastic IP

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19
Q

An Elastic IP is a what kind of IP?

A

public IPv4

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20
Q

How many instance can you attach an Elastic IP too?

A

One

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21
Q

How many Elastic IPs can you have by default

A

5

22
Q

By Default, your EC2 machine comes with what set of IPs if any?

A

Public, for www

Private IP for the internal AWS network.

23
Q

T /F: When SSH’ing into our EC2 instance, we use the private IP.

A

False. We use the public because we are not on the same network to use private.

24
Q

EC2: You can bootstrap an instance using ___?

A

EC2 User Data script

25
Q

What does bootstraping mean?

A

Means launching commands when a machine starts.

26
Q

The EC2 User Data Script runs with what user?

A

Root user

27
Q

What are the 4 EC2 Instance Launch Modes?

A

On demand
Reserved
Spot Instances
Dedicated Hosts

28
Q

Describe On Demand Instances?

A

short workload, predictable pricing

29
Q

Reserved Instances

A

long workloads (>= 1 year)

30
Q

Spot Instances

A

short workloads, for cheap, can lose instances

31
Q

Dedicated Hosts

A

book an entire physical server, control instance placement

32
Q

Dedicated Instances

A

no other customers will share your hardware

33
Q

Describe ‘On Demand EC2 Instance’

A
  • Pay for what you use (billing per second, after the first minute)
  • Has the highest cost but no upfront payment
  • No long term commitment
34
Q

In what case should you use EC2 On Demand Instances?

A

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

35
Q

Reservation period for a ‘Reserved Instance’ can be what?

A

1-3 years

36
Q

Can receive up to __ percent discount on Reserved Instances compared to On-demand

A

75%

37
Q

This type of instance is recommended for steady state usage applications?

A

Reserved Instances

38
Q

Can receive up to __ percent discount on Spot Instances

A

90%

39
Q

This type of Instance allows you to bid a price and get the instance as long as its under the price

A

Spot Instance

40
Q

This type of instance is good for batch jobs, big data analysis, or workloads that are resilient to failures

A

Spot Instances

41
Q

This type of instance is useful for software that have complicated licensing model (BYOL) or for companies that have strong regulatory or compliance needs.

A

EC2 Dedicated Hosts

42
Q

It’s now possible to have an unlimited burst credit balance for burstable EC2’s

A

True

43
Q

T2 / T3 what what kind of EC2 Instances?

A

Burstable

44
Q

What’s an AMI?

A

an image to use to create our instances

45
Q

T / F: AMI’s can be used in multiple regions?

A

False. AMIs are built for a specific AWS region.

46
Q

What are the two strategies for placement groups?

A

Cluster, Spread

47
Q

Describe Cluster Placement Group

A

Cluster—clusters instances into a low-latency group in a single Availability Zone

48
Q

Application that needs extremely low latency and high network throughput could make use of this>

A

Placement Groups Cluster. Great network (10Gbps bandwith btw instances)
Cons: If rack fails, all instances fail.

49
Q

How man EC2 Instances are allowed per AZ placement group?

A

7

50
Q

Placement Groups can span across AZ’s?

A

True

51
Q

EC2 instances are billed by the?

A

Second