Varnish - HTTP Accelerator Crash Course

Varnish is a reverse proxy web accelerator Written in C designed to improve HTTP performance by using server side caching. In this video I’m going to go through how Varnish works, we will spin up a Varnish docker container and finally talk about the pros and cons of this tech. Chapters 0:00 Intro 1:53 Classic HTTP Architecture 3:50 How Varnish Works 7:50 Demo HTTP 18:23 Demo HTTPS 28:43 Varnish Pros 39:26 Varnish Cons Agenda * Classic HTTP Architecture * How Varnish Works? * HTTP Setup - Varnish * HTTPS Setup - Varnish with Caddy as TLS Terminator. * Varnish Pros & Cons * Summary Pros * Cache & prefetching documents * Resolve DNS hostnames in documents  * Rewrite scripts to optimize code * Load Balancing  * Backend Connection Pooling * Varnish Modules (VMODS, e.g. rewrite headers)  * Edge side includes (personalized dynamic page) Cons * Cache Invalidation * Only works on unencrypted HTTP * For HTTPS frontend, terminate TLS * For HTTPS backend, no solution in Varnish open source * Can’t cache POST requests (e.g. GraphQL queries) * HTTP/2 backends won’t benefit docker commands docker run --name varnish -p 8080:80 varnish docker cp default.vcl varnish:/etc/varnish default.vcl vcl 4.0; backend default { .host = "husseinmac"; .port = "2015"; } Cards: Connection Pooling 2:15 https://www.youtube.com/watch?v=GTeCtIoV2Tw Layer 4 vs Layer 7 Load balancing 6:25 https://www.youtube.com/watch?v=aKMLgFVxZYk GET vs POST 6:48 https://www.youtube.com/watch?v=K8HJ6DN23zI Postgres NodeJS Chrome 8:23 https://www.youtube.com/watch?v=0JNq46eFuOM Redis 46:13 https://www.youtube.com/watch?v=sVCZo5B8ghE TLS Termination 49:35 https://www.youtube.com/watch?v=H0bkLsUe3no Resources edge side includes https://www.fastly.com/blog/using-esi-part-1-simple-edge-side-include Cache invalidation varnish https://www.smashingmagazine.com/2014/04/cache-invalidation-strategies-with-varnish-cache/ Varnish Doc https://varnish-cache.org/docs/ 🏭 Software Architecture Video