Igeometry Podcast

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. 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 v