When I went through some of the tutorials online, it showed that only the worker nodes have the container runtime. But from my understanding, it seems master nodes also run some pods such as etcd and the api server components to ensure the cluster functions properly and thus has kubelet. Can anyone please correct me if I'm wrong and answer my question if possible?
Master nodes have CRI too, verify it using: kubectl get nodes -o wide.
When a Kubernetes cluster is first set up, a Taint is set on the master node. This automatically prevents any pods from being scheduled on this node. But, it's definitely possible to run pods on the master node. However, best practice is not to deploy application workloads on a master server.
In terms of tutorials, I believe it's just to keep things simple.