AWS Study - EC2

Question 1

What is Elastic Compute Cloud (EC2)?

Answer 1

A cloud computing service that allows you to launch virtual server instances on the AWS cloud.

Question 2

What can you configure when launching an EC2 instance?

Answer 2

You can configure the OS, storage, memory, and network throughput.

Question 3

What are the types of EC2 Instance Types?

Answer 3

• General-purpose
• Compute Optimized
• Memory-Optimized
• Accelerated Optimized
• Storage optimized

Question 4

How can you access your EC2 instance?

Answer 4

With SSH via a key pair provided by AWS.

Question 5

What is a key pair in AWS EC2?

Answer 5

Consists of a public key stored by AWS and a private key file that you store.

Question 6

What is the purpose of Placement Groups in EC2?

Answer 6

To choose the logical placement of your instances to optimize for communication, performance, or durability.

Question 7

What is Userdata in EC2?

Answer 7

A script that runs automatically when launching an EC2 instance.

Question 8

What is Metadata in EC2?

Answer 8

Data about the current instance accessed via a local endpoint when SSH into the EC2 instance.

Question 9

What does EC2 compute units (ECU) measure?

Answer 9

The relative measure of the integer processing power of an Amazon EC2 instance.

Question 10

What are the four pricing models for EC2?

Answer 10

• On-demand
• Spot
• Reserved Instances (RI)
• Dedicated

Question 11

What is the use case for On-demand pricing in EC2?

Answer 11

Short term, spiky, unpredictable workloads, and first-time apps.

Question 12

What is Reserved Instances (RI) in EC2?

Answer 12

A pricing model that offers up to 75% off for predictable usage applications.

Question 13

What are the payment options for Reserved Instances?

Answer 13

• All Upfront
• Partial Upfront
• No Upfront

Question 14

What is Spot Pricing in EC2?

Answer 14

A pricing model that offers up to 90% off for spare computing capacity.

Question 15

What is the use case for Dedicated Hosting in EC2?

Answer 15

When you need a guarantee of isolation hardware for enterprise requirements.

Question 16

What is a Savings Plan in AWS EC2?

Answer 16

A flexible pricing model offering savings in exchange for a commitment to consistent usage.

Question 17

What information does an Amazon Machine Image (AMI) hold?

Answer 17

• A template for the root volume
• Launch permissions
• Block device mapping

Question 18

What type of IP addresses can be assigned to an EC2 instance?

Answer 18

• Public
• Private
• Elastic IP

Question 19

What is an Elastic IP

Answer 19

A static, public IPv4 address in the Amazon AWS cloud, which can be associated with an instance, remains consistent even if the instance is stopped or restarted.

Question 20

What is an Elastic Network Interface (ENI)?

Answer 20

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

Question 21

What is Enhanced Networking in EC2?

Answer 21

Provides higher bandwidth and lower inter-instance latencies using an Elastic Network Adapter (ENA).

Question 22

What is the Elastic Fabric Adapter (EFA)?

Answer 22

An AWS Elastic Network Adapter with capabilities for high levels of inter-node communications.

Question 23

What are the configurations of Placement Groups?

Answer 23

• Cluster
• Spread
• Partition

Question 24

What is VM Import/Export used for?

Answer 24

To migrate VMware, Microsoft, XEN VMs to the cloud and convert EC2 instances back to VMs.

Question 25

What is an Autoscaling Group (ASG) in EC2?

Answer 25

A collection of EC2 instances grouped for scaling and management.

Question 26

What does the Desired Capacity in an ASG represent?

Answer 26

How many EC2 instances you want to ideally run.

Question 27

What is a Cooldown Period in Auto Scaling?

Answer 27

A configurable setting that helps to ensure that scaling actions do not occur too frequently.

Question 28

What is the purpose of the Simple Scaling policy with steps?

Answer 28

Allows you to create steps based on escalation alarm values

Question 29

What does a scheduled action in Auto Scaling determine?

Answer 29

A specific event or time to trigger auto-scaling

Question 30

What does 'desired capacity' refer to in Auto Scaling?

Answer 30

How many EC2 instances you want to ideally run

Question 31

What does an Auto Scaling Group (ASG) always launch instances to meet? | Think about the capacity

Answer 31

Minimum capacity

Question 32

What is the purpose of a health check in Auto Scaling?

Answer 32

Determine the current state of an instance

Question 33

What is the default cooldown period for an Auto Scaling group?

Answer 33

300 seconds

Question 34

Health checks can be run against which two entities?

Answer 34

ELB or EC2 instance

Question 35

What is a Launch Configuration in Auto Scaling?

Answer 35

Holds the configuration values for instances, such as AMI, instance type, role

Question 36

Can Launch Configurations be edited?

Answer 36

No, they must be cloned or a new one created

Question 37

What are the four scaling options available in Auto Scaling?

Answer 37

* Maintain * Manual * Scheduled * Dynamic

Question 38

How can Auto Scaling scale based on Amazon SQS?

Answer 38

Uses a custom metric sent to CloudWatch measuring messages in the queue per EC2 instance

Question 39

What are the three types of Elastic Load Balancers (ELB)?

Answer 39

* Network Load Balancer (NLB) * Application Load Balancer (ALB) * Classic Load Balancer (CLB)

Question 40

What is required for an Application Load Balancer (ALB) in terms of Availability Zones?

Answer 40

Must have at least 2 AZs

Question 41

What is the routing layer of the Application Load Balancer (ALB)?

Answer 41

Operates at the request level (Layer 7)

Question 42

What types of routing does the Application Load Balancer (ALB) support?

Answer 42

* Path-based routing * Host-based routing * Query string parameter-based routing * Source IP-based routing

Question 43

What does the Network Load Balancer (NLB) operate at?

Answer 43

Connection level (Layer 4)

Question 44

What type of traffic is the Classic Load Balancer (CLB) intended for?

Answer 44

Existing applications running in EC2-Classic

Question 45

Which load balancer is recommended for new applications?

Answer 45

Application Load Balancer (ALB) or Network Load Balancer (NLB)

Question 46

What is the purpose of the X-forwarded-for (XFF) header?

Answer 46

To get the original IP of incoming traffic passing through ELB

Question 47

Can you attach a Web Application Firewall (WAF) to all types of ELBs?

Answer 47

No, only to ALB

Question 48

What is cross-zone load balancing?

Answer 48

Distributes requests evenly across registered instances in all enabled Availability Zones

Question 49

Is cross-zone load balancing enabled by default for ALB?

Answer 49

Yes, it is always on and cannot be disabled

Question 50

What happens when connection draining is in action for a CLB?

Answer 50

CLB will be in the status 'InService: Instance deregistration currently in progress'