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 varnish:/etc/varnish default.vcl vcl 4.0; backend default { .host = "husseinmac"; .port = "2015"; } timecodes Classic HTTP Architecture : 1:53 How Varnish Works 3:50 Demo HTTP 7:50 Demo HTTPS 18:23 Varnish Pros 28:43 Varnish Cons 39:26 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 tags: varnish http accelerator, varnish pros and cons, varnish with https, varnish disadvantages 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/ ——

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