A sidecar proxy is an application design pattern which abstracts certain networking features, such as inter-service communications, monitoring and security, timeouts, retries, communication protocols, away from the main architecture to ease the maintenance of the application as a whole.
In this video I’d like to talk about how we classically do things:

Library Pattern

getComments HTTP1:1/JSON
Add features retries/timeout /hardcode the server name what it changed/add new server to load balance between them/credentials


Sidecar pattern

getComments HTTP/2


Sidecar proxy/container

Examples

Microservices (Linkerd, Envoy, Istio)

Pros

Language agnostic (polyglot)
Protocol upgrade
Security
Tracing and Monitoring
Service Discovery
Caching

Cons

Complexity
Latency
SideCar Proxy must be layer 7

Library 2:25
Sidecar: 7:40
Example: 13:00 (https://www.youtube.com/watch?v=cp3Ku1XeOn8)
Pros & Cons : 16:15
Cards
6:22 HTTP/2
10;50 Reverse Proxy / proxy
example 13:00 (https://www.youtube.com/watch?v=cp3Ku1XeOn8)
16:00 Layer 4 vs Layer 7 load balancer