Section 7: ELB & ASG

Question 1

Scalability is

Answer 1

the ability to accommodate a larger load by making the hardware stronger (scale up), or by adding nodes (scale out)

Question 2

Vertical Scalability is

Answer 2

The increasing in size of an instance.

Question 3

Horizontal Scalability is the same as

Answer 3

Elasticity

Question 4

What is Horizonal Scalability?

Answer 4

It is the increase of the number of instances/systems for an application.

Question 5

Vertical scalability is useful for

Answer 5

Distributed systems such as a database

Question 6

High availability is the ability to

Answer 6

Run instances for the same application across multi AZ

Question 7

Load Balancers are

Answer 7

Servers that forward internet traffic to multiple
servers (EC2 Instances) downstream

Question 8

Why use a load balancer?

Answer 8

*Spread load across multiple downstream instances
*Expose a single point of access (DNS) to your application
*Seamlessly handle failures of downstream instances
*Do regular health checks to your instances
*Provide SSL termination (HTTPS) for your websites
*High availability across zones

Question 9

ELB is

Answer 9

An AWS managed load balancer

Question 10

Application Load Balancer

Answer 10

• HTTP / HTTPS / gRPC
  protocols (Layer 7)
• HTTP Routing features
• Static DNS (URL)

Question 11

Network Load Balancer

Answer 11

• TCP / UDP protocols
  (Layer 4)
• High Performance: millions of
  request per seconds
• Static IP through Elastic IP

Question 12

Gateway Load Balancer

Answer 12

• GENEVE Protocol on
  IP Packets (Layer 3)
• Route Traffic to Firewalls that
  you manage on EC2 Instances
• Intrusion detection

Question 13

The goal of an Auto Scaling Group (ASG) is to

Answer 13

• Scale out (add EC2 instances) to match an increased load
• Scale in (remove EC2 instances) to match a decreased load
• Ensure we have a minimum and a maximum number of machines running
• Automatically register new instances to a load balancer
• Replace unhealthy instances

Question 14

Manual Scaling

Answer 14

Update the size of an ASG manually

Question 15

Dynamic Scaling

Answer 15

Respond to changing demand

Question 16

Simple / Step Scaling

Answer 16

Scales based on alarms

Question 17

Target Tracking Scaling

Answer 17

Scales based on set targets

Question 18

Scheduled Scaling

Answer 18

Anticipate a scaling based on known usage patterns

Question 19

Predictive Scaling

Answer 19

• Uses Machine Learning
  to predict future traffic
  ahead of time
• Automatically
  provisions the right
  number of EC2
  instances in advance