Load Balancing Flashcards
What is a Load Balancer?
A virtual Machine that balances loads. 3 types.
1) Application
2) Network
3) Classic
Application Load Balancer:
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.
Network Load Balancer:
Best suited for load balancing TCP traffic.
Operates at layer 4.
Used when you require ultra low latencies.
Classic Load Balancer:
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)
Load Balancer : 504 error
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.
What is the IP address of your Elastic load balancer?
There are no IP addresses associated with ELBs, they use DNS names only.
How are instances monitored by ELB reported?
1) InService (functioning)
2) OutOfService (Not functioning)