Kubernetes only pays off once the cluster state lives in a repository rather than in the administrator's memory. This area covers the design of small highly available clusters, networking and storage for containers, and GitOps as a way of working rather than just a tool.
A Docker daemon in the pipeline means a privileged container with access to the host. There are tools that build images from the same Dockerfile without that cost; they differ in what they demand from the cluster.
A script executes steps. GitOps maintains state. That difference decides what happens when somebody changes something on the cluster by hand.
Three nodes and etcd are not enough to call a cluster highly available. The points that break most often in small Kubernetes clusters, and how to design around them.
A GitOps-managed cluster can be rebuilt from scratch in an hour. That does not mean it needs no backups: it needs them for exactly the things the repository does not contain.
Containers have not replaced virtual machines and will not. How to split workloads between classic virtualisation and a container platform without ideology.