Infrastructure Notes

Short write-ups on servers, networking and things that broke.

Tuning TCP congestion control on small VPS instances

A few notes on queue disciplines and why the defaults rarely match a 1 vCPU box with a gigabit uplink.

Certificate renewals without downtime

Moving from standalone challenges to webroot, and what that changes when another service already holds the port.

Reading ss output properly

UDP and TCP listeners on the same port number are not a conflict. A short reminder to myself.