High Availability and Scalability

Question 1

A Type of ELB that is very useful for extreme performance, TCP or UDP Traffic

Answer 1

Network Load Balancer (v2)

Question 2

How many static IP does an NLB has per AZ?

Answer 2

NLB has one static IP per AZ and supports Elastic IP (helpgul for whitelisting speciifc IP)

Question 3

What are the valid Target Groups for a Network Load Balancer?

Answer 3

EC2 Instances
IP Addresses - must ne private IPs
Application Load Balancer

Question 4

It can be used to Deploy, scale and amnage fleet of 3rd party network, virtual applicances in AWS

Example Firewalls, Intrusion Detection, and Prevention System, Deep packet Inspection and payload manipulation at the network level

Answer 4

Gateway Load balancer

Question 5

What are the valid Taget Groups for Gateway Load Balancer

Answer 5

EC2 Instances
IP Addresses – must be private

Question 6

It is possible to implement stickiness so that the same client is always redirected to the same instance behind a load balancer

Answer 6

Sticky Session (Session Affinity)

Question 7

How does an Application\Network Load Balancer implement Session Affinity or Sticky Sessions?

Answer 7

By Using cookies

Question 8

What are the two types of cookies used by ELB?

Answer 8

Application-based cookie and Duration-based cookie

Question 9

This solves the problem of loading multiple SSL certificates onto one web server (to serve multiple websites) It is a newer protocol and requires to indicate the hostname of the target server in the initial SSL Handshake. Only works with ALB and NLB

Answer 9

SSL – Server Name Indication

Question 10

It’s goal is to Scale Out (add EC2 Instances) to match an increased load and Scale in (remove EC2 instances) to match the decreased load.

Answer 10

Auto-Scaling Group

Question 11

What is inside a Launch Template for ASG?

Answer 11

AMI, Instance type, EBS, IAM Role, Security Group, VPC

Question 12

ASG - Scaling Policy
What Dynamic Scaling can you use for this use case below

I want the average ASG CPU to stay at around 40%

Answer 12

Target Tracking Scaling

Question 13

ASG - Scaling Policy
What Dynamic Scaling can you use for this use case below:

When a CloudWatch Alarm is triggered (example CPU >70%), then add 2 units

When a CloudWatch alarm is triggered (example CPU < 30 %), then remove 1

Answer 13

Simple / Step Scaling

Question 14

ASG - Scaling Policy
What Dynamic Scaling can you use for this use case below:

Anticipate a scaling based on known usage paterns

Example: increase the min capacity to 10 at 5 pm on Fridays

Answer 14

Scheduled Scaling

Question 15

ASG - Scaling Policy
What Dynamic Scaling can you use for this use case below:

Contnuously forecast load and schedule scaling ahead

Answer 15

Predictive Scaling

Question 16

During this period, the ASG will not launch or terminate additional instances (to allow for metric to stabilize)

Answer 16

ASG - Scaling CoolDowns

Question 17

Application Load balancers can route traffic to different target groups.
Enumerate the target groups

Answer 17

Hostname, Request URL, SourceIP

Question 18

What can you use to get original IP of incoming traffic passing through ELB?

Answer 18

Use X-Forwarded-For (XFF)

Question 19

ALB has an advanced feature where you can route based on sub-domain header, path, and other HTTP(s) information

Answer 19

ELB Request Routing