ELB & ASG

Question 1

What is Vertical Scalability?

Answer 1

Means increasing the size of an instance.

Example: 4 GB RAM instance to 8 GB RAM instance.

Question 2

What is Horizontal Scalability?

Answer 2

Means increasing the number of instances / systems for your application.

Example: Having a single 4 GB RAM instance and then spinning up three more 4 GB RAM instances.

Question 3

What is High Availability?

Answer 3

High Availability means running your application / system in at least 2 availability zones.

Question 4

Define Scalability.

Answer 4

The ability to accommodate a larger workload by scaling up or scaling out.

Question 5

Define Elasticity.

Answer 5

The ability for a system to scale based on load.

Question 6

Define Agility.

Answer 6

The ability to reduce the time to make resources available to users (minutes).

Question 7

What is a load balancer?

Answer 7

Servers that forward internet traffic to multiple servers downstream.

Question 8

Why use a load balancer?

Name at least 3 points.

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 for your websites.

HA across zones.

Question 9

What is an ELB (Elastic Load Balancer)?

Answer 9

A managed load balancer.

Question 10

What are the 3 types of load balancers offered by AWS?

Answer 10

Application Load Balancer
Network Load Balancer
Classic Load Balancer

Question 11

What is an Auto Scaling Group (ASG)?

Answer 11

Allows you to create and get rid of servers very quickly based on load.

Question 12

What are the 5 goals of an Auto Scaling Group?

Answer 12

1. Scale out to match increased load
2. Scale in to match decreased load
3. Ensure we have a min./max. # of machines
4. Auto register new instances to a load balancer
5. Replace unhealthy instances

Question 13

Which AWS offered Load Balancer should you use to handle hundreds of thousands of connections with low latency?

Answer 13

A Network Load Balancer can handle millions of requests per second with low-latency. It operates at Layer 4, and is best-suited for load-balancing TCP, UDP, and TLS traffic with ultra high-performance.

Question 14

Changing an EC2 Instance Type from a t3a.medium to a t3a.2xlarge is an example of?

Answer 14

Vertical scaling.

Question 15

What can you use to handle quickly and automatically the changing load on your websites and applications by adding compute resources?

Answer 15

An Auto Scaling Group (ASG)

Question 16

True or False?

Auto Scaling Groups can automatically change EC2 instance types.

Answer 16

False.

Auto Scaling Groups can add or remove instances, but from the same type. They cannot change the EC2 Instances Types on the fly.

Question 17

Which Load Balancer is best suited for HTTP/HTTPS load balancing traffic?

Answer 17

Application Load Balancers are used for HTTP and HTTPS load balancing. They are the best-suited for this kind of traffic.`