Elastic Load Balancer (ELB) Flashcards
What are the 3 different types of ELB available?
- Application Load Balancer ALB (HTTP/HTTPS)
- Network Load Balancer NLB (TCP/UDP)
- Classic Load Balancer CLB (Legacy)
What are the three components of ELB?
Listeners
Incoming traffic is evaluated against listeners. Listeners evaluate any traffic that is matches the Listener’s port. For Classic Load Balancer, EC2 instances are directly registered to the Load Balancer.
Eg. Port 80 or 443
Rules (Not avaliable for Classic Load Balancer)
Listeners will then invoke rules to decide what to do with the traffic. Generally the next step is to forward traffic to a Target Group
Target Groups (Not avaliable for Classic Load Balancer) EC2 instances are registered as targets to a Target Group
For Application Load Balancer (ALB) or Network Load Balancer (NLB), How does ELB work?
How is the flow? There are 6 steps
- xx.xx (Route 53)
- ALB or NLB
- Listeners: Listener Port 80
- Rule: redirect to Port 443
- Listener Port 443
- Rule: forward to Target 1 (EC2 instances)
For Classic Load Balancer (CLB) traffic is sent to the Listeners. When the port matches it then it forwards the traffic to any EC2 instances that are registered to the Classic Load Balancer. CLB does not allow you to apply rules to listeners.
How does it work? How is that flow? 4 steps…
- xx.xx (Route 53)
- CLB
- Listeners: Listener Port 80 and Listener Port 443
- Registered Targets
Which ELB component does incoming traffic hit first?
Listener
Which type of load balancers forwards traffic directly to EC2 instances without using a target group?
Classic Load Balancer
To associate an Application or Network load balancer with EC2 instances you must use one of these
Target Groups
This type of load balancer does not support creating rules on the listener
Classic Load Balancer
Application Load Balancers (ALB) are designed to…
Balance HTTP and HTTPS traffic.
What can you attach to an ALB?
Web Application Firewall (WAF)
Great for Web Applications
Which layer of the OSI model does an Application Load Balancer (ALB) operate on?
They operate at Layer 7 (of the OSI Model).
Layer 7 - Application Layer
The Application Load Balancer (ALB) feature that allows adding rules to a listener based on the HTTP protocol?
Request Routing
The host-based routing feature allows you to write rules that use the Host header to route traffic to the desired target group. T
Network Load Balancers are designed to…
balance TCP/UDP.
Which layer of the OSI model does a Network Load Balancer (NLB) operate on?
A Network Load Balancer (NLB) operates on the “Layer 4 - Transport Layer” of the OSI Model
Which type of load balancer is designed for optimum network performance?
Network Load Balancer
- Great for Multiplayer Video Games or When network performance is critical