Argo CD

The problem it solves

A GitOps controller that syncs a Kubernetes cluster with a Git repository.

Technical rationale

Argo CD makes the gitops repository the only description of the cluster: nothing else writes to it, so a difference between the repository and what runs is a visible fact rather than a suspicion. That is also what makes a deployment reviewable, because the change arrives as a commit with its digest instead of a command typed into a terminal.

How I have used it

It applies every commit from the gitops repository onto the homelab cluster; nothing else writes to it.