ELB

Question 1

ELB types

Answer 1

• Application Load Balancers
• Network Load Balancers
• Classic Load Balancers

Question 2

Limitation of Application Load Balancers

Answer 2

Only support HTTP and HTTPS

Question 3

HTTPS Load balancing

Answer 3

To use an HTTPS listener, you must deploy at least one SSL/TLS server certificate on your load balancer. The load balancer uses a server certificate to terminate the frontend connection and then decrypt requests from clients before sending them to the targets.

Question 4

In which layer does Network Load Balancers operate?

Answer 4

At layer 4

Question 5

When to use Network Load Balancers?

Answer 5

• When you need extreme performance

- When you need protocols not supported by Application Load Balancers

Question 6

Can Network Load Balancers? decrypt traffic?

Answer 6

Yes, but you will need to install the certificate on the load balancer

Question 7

What does 504 (Gateway timeout) mean in a Classic Load Balancer?

Answer 7

This means that the application is not responding within the idle timeout period

Question 8

How to get the IPv4 address of the user with a Classic Load Balancer?

Answer 8

Look for the X-Forwarded-For header

Question 9

Can sticky sessions be enabled for Application Load Balancers?

Answer 9

Yes, but the traffic will be sent at the target group level

Question 10

An EC2 instance is removed from a pool, but the load balancer continues to direct traffic to that EC2 instance. How to solve it?

Answer 10

Disable sticky session

Question 11

What are sticky sessions used for?

Answer 11

Enable your users to stick to the same EC2 instance. Can be useful if you are storing information locally on that instance.

Question 12

What happens if the deregistration delay is enabled?

Answer 12

Existing connections are kept open if the EC2 instance becomes unhealthy.

Question 13

What happens if the deregistration delay is disabled?

Answer 13

The load balancer will immediately close connections to the instances that are de-registering or have become unhealthy.

Question 14

In which layer does Application Load Balancers operate?

Answer 14

Layer 7

Question 15

In which layer does Classic Load Balancers operate?

Answer 15

Layer 4/7

Question 16

What are Health Checks used for in load balancers?

Answer 16

To route your traffic to instances or targets that are healthy

Question 17

Components of Application Load Balancers

Answer 17

• Listeners: A listener checks for connection requests from clients, using the protocol and port you configure
• Rules: Determine how the load balancer routes request to its registered targets. Each rule consists of a priority, one or more actions, and one or more conditions.
• Target Groups: Each target group routes requests to one or more registered targets, such as EC2 instances, using the protocol and por numbers you specify.