Load balancing is process of balancing incoming requests to multiple machines, processes or services. In this video we will explain two types of load balancers, layer 4 and layer 7.

Layer 4 - haproxy, NLB

Pros

- great for simple packet-level load balancing

- Fast and efficient doesn’t look at the data

- More secure as it cant really look at your packets. So if it was compromised no one can look

- Uses NAT - One connection between client and server NATed

Cons

- Can't do smart load balancing based on the content, such as switch request based on the requested media type

- Cant do microservices with this type

- Has to be sticky as it is a stateful protocol (all segments)

Layer 7 (Nginx , haproxy)

This type of proxy actually looks at the content and have more context, it knows you are visiting the /users resources so it may forward it to a different server. Essential and Great for microservices , it knows the content is video:image etc..

Episode 125 - Layer 4 vs Layer 7 Load Balancing