ELB (Elastic Load Balancing) & ASG (Auto Scaling Group)

Question 1

High Availability

Answer 1

That means that you have your applications across multiple availability zones (AZ)

Question 2

Scalability

Answer 2

There is vertical and horizontal scaling.

Vertical scaling means that you increase the size of your instance and horizontal scaling means that you increase the number of your instances.

Question 3

Elasticity

Answer 3

This means that you are able to scale up and down depending on demand.

Question 4

Agility

Answer 4

Concept of the cloud, that enables you to work faster because you can create and delete resources very quickly.

Question 5

ELB

Answer 5

Elastic Load Balancers allow us to distribute traffic across the backend of your EC2 instances. The ELB and the EC2 instances can be set up across multiple AZ, therefore, enabling us to be highly available. ELBs support health checks to make sure that the EC2 instances in the backend are working.

Question 6

Types of Load balancers

Answer 6

1) Application Load balancer (HTTP - Layer 7)
2) Network Load balancer (TCP - Layer 4)
3) Classic Load balancer

Question 7

ASG

Answer 7

When we distribute the traffic to multiple EC2 instances it is good for us to scale them through an auto scaling group (ASG).

ASG uses horizontal scaling to add instances across multiple availability zones, replaces unhealthy instances (EC2s), and automatically registers new instances to a load balancer.

ASG can add or remove instances of the same type. They cannot chance EC2 Instance Types on the fly.

Question 8

Auto Scaling Strategies

Answer 8

Auto Scaling Strategies include: Manual Scaling, Dynamic Scaling (Simple/Step Scaling, Target Tracking Scaling, Scheduled Scaling), and Predictive Scaling.