Route 53

Question 1

Network Load Balancers

Answer 1

Network Load Balancers operate @ layer 4

Use when you need extreme performance

Other use cases are where you need protocols not supported by the App Load Balancer

Network Load Balancers can decrypt traffic, but you will need to install the cert on the load balancer

Question 2

Classic Load Balancer

Answer 2

504 error means the gateway has timed out

This means the app is not responding w/in the idle timeout

Pull an end users IPv4 address look for the X-forwarded-for header good for getting gen location

Question 3

Application Load Balancer: Listeners

Answer 3

Listeners: Check for connection requests from clients. using the protocol & port you configure (either port 80 or 443)

Question 4

Application Load Balancer: Rules

Answer 4

Determine how the load balancer routes requests to its registered targets. Each rule consists of a priority, one or more actions, and one or more conditions

Question 5

Application Load Balancers: Target Groups

Answer 5

Each target group routes requests to one or more registered targets, such as EC2 instances, using the protocol & port # you specify

Question 6

Application Load Balancer: Limitations

Answer 6

App Load Balancers only support HTTP & HTTPS

Question 7

Application Load Balancer: HTTPS

Answer 7

To use an HTTPS listener you must deploy @ least one SSL/TLS server cert on your load balancer

The load balancer uses a server cert to terminate the front end connection & then decrypt the requests from clients before sending them to targets

Question 8

Load Balancer Types

Answer 8

1. Application Load Balancer (Layer 7)
2. Network Load Balancer (Layer 4)
3. Classic Load Balancer (Layer 4/7)

Question 9

Load Balancer Health Checks

Answer 9

You use Health Checks to route your traffic to instances or targets that are healthy

Question 10

Sticky Sessions

Answer 10

Enable your users to stick to the same EC2 instance. Can be useful if you’re storing info locally to the instance

You may see a scenario based question where you remove an EC2 instance from a pool, but the load balancer continues to direct traffic to that EC2 instance
To fix disable sticky sessions

Application Load Balancers also have sticks sessions but that traffic will be sent @ the target group level

Question 11

Deregistration Delay / Connection Draining

Answer 11

Enable Deregistration Delay

Keeps existing connections open if an EC2 instance becomes unhealthy

Disable Deregistration Delay

Do this if you want your load balancer to immediately close connections to the instances that are de-registering or have become unhealthy