Load Balancing

Question 1

What is a Load Balancer?

Answer 1

A virtual Machine that balances loads. 3 types.

1) Application
2) Network
3) Classic

Question 2

Application Load Balancer:

Answer 2

Best suited for loading balancing HTTP and HTTPS traffic.
Operate at layer 7.
Can create advanced request routing.
Send specific requests to a specific host.

Question 3

Network Load Balancer:

Answer 3

Best suited for load balancing TCP traffic.
Operates at layer 4.
Used when you require ultra low latencies.

Question 4

Classic Load Balancer:

Answer 4

Classic are also called Elastic Load Balancers.
These are legacy elastic load balancers.
* You can use HTTP/HTTPS
* You can see layer 7 or Layer 4.
* It leverages x-forwarded-for headers.(shows public IPv4 addresses)

Question 5

Load Balancer : 504 error

Answer 5

This is a gateway timeout and it means that the application is not responding within the idle timeout period.
Check: Application, web server or database server.

Question 6

What is the IP address of your Elastic load balancer?

Answer 6

There are no IP addresses associated with ELBs, they use DNS names only.

Question 7

How are instances monitored by ELB reported?

Answer 7

1) InService (functioning)

2) OutOfService (Not functioning)