some notes on kubernetes ingress

Mon, 14 Jul 2025 00:00:00 +0000

I keep re-learning how ingress actually routes traffic, so here are the notes I wish I’d written the first time.

the mental model

An Ingress object is just configuration. On its own it does nothing — you need an ingress controller running in the cluster to read those objects and actually route traffic.

a minimal example

Here’s the smallest thing that does something useful:

how does systemd actually start things?

Sun, 22 Jun 2025 00:00:00 +0000

I’ve typed systemctl start thousands of times without really knowing what happens after I hit enter. Here’s what I pieced together.

units all the way down

Everything systemd manages is a unit. A service is a unit, a mount is a unit, a timer is a unit. They’re defined in plain text files, which is nice — you can read them.

systemctl cat sshd.service

dependencies are the interesting part

The thing I didn’t appreciate: systemd builds a dependency graph and starts things in parallel wherever it can. Wants= and Requires= describe ordering intent, and After= / Before= describe actual ordering.