Episode 125 - Layer 4 vs Layer 7 Load Balancing

The Backend Engineering Show with Hussein Nasser - A podcast by Hussein Nasser

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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..