Elasticity and Scaling EC2

Question 1

What does ELB stand for?

Answer 1

Elastic Load Balancing

Question 2

What is ELB?

Answer 2

Elastic Load Balancing

Simplified Definition:
An ELB evenly distributes triffic between EC2 instances that are associated with it. This helps to prevent one server from becoming overloaded and potentially crashing.

AWS Definition:
A load balancer distrubtes incoming application traffic across multiple EC2 instances in multiple Availability Zones. This increases the fault tolerance of you applications. Elastic Load Balancing detects unhealthy instances and routes trafic only to healthy instances.

Question 3

ELB is a foundational component of what two things?

Answer 3

1. High availability

2. Fault tolerance

Question 4

What is Auto Scaling?

Answer 4

Simplified Definition:
Auto Scaling automates the process of adding (scaling up) or removing (scaling down) EC2 instnaces based on traffice demand for your application.

AWS Definition:
Auto Scaling helps you ensure that you have the correct number of EC2 instances available to handle the load for your application. You create collections of EC2 instances, called Auto Scaling groups. You can specify the minimum number of instances in each Auto Scaling group, and Auto Scaling ensures that your group never goes below this size. You can specify the maximum number of instances in each Auto Scaling group, and Auto Scaling ensures that your group never goes above this size. If you specify desired capacity, either when you create the group or at any time thereafter, Auto Scaling ensures that your group has this many instances. If you specify scaling policies, then Auto Scaling can launch or terminate instnaces as demand on your application increases or decreases.

Question 5

Auto Scaling builds on the benefits of Elastic Load Balancing (ELB) while adding what two benefits?

Answer 5

1. Scalability

2. Elasticity

Question 6

What is an Auto Scaling Group?

Answer 6

A logical grouping of EC2 instnaces for the purpose of scaling.

Question 7

Which is NOT a benefit of ELB?

a. Routes traffice to healthy instances
b. Increase an applications fault tolerance
c. Scale-out EC2 resources to meet demand
d. Distributes traffic across EC2 instances

Answer 7

C. ELB does not scale-out EC2 recourses. An Auto Scaling Group will scale-out EC2 resources based on demand.

Question 8

Which of the following will allow us to distribute traffic amongst the EC2 instances?

a. VPC
b. S3
c. Auto Scaling Group
d. ELB

Answer 8

D

Question 9

What combo of AWS services will achieve high availability, fault-tolerance, scalability, and elasticity?

a. EC2 and ELB
b. EC2 and Auto Scaling Group
c. EC2
d. EC2, ELB, and Auto Scaling Group with automation

Answer 9

D

Question 10

We have an ELB balancing traffic between two instances, but the instances are reaching capacity. What could we do to automate a solution for handling the traffic?

a. Add another EC2 instance.
b. Terminate an EC2 instance.
c. Create an Auto Scaling Group.
d. Create another ELB.

Answer 10

C