Prepare a Node for kubeadm with cri-dockerd
This is one of those CKA tasks with no manifest to copy from the docs. You prepare a plain Linux box so kubeadm can use Docker as the runtime. It is pure system administration, and you have to know the steps cold. Let's walk through it.
This is a CKA Cluster Architecture, Installation & Configuration walkthrough. Every command below is real output from a live cluster, and you can reproduce the whole thing yourself (scripts at the end).
The scenario
Docker is already installed on this node, but kubeadm cannot talk to Docker directly anymore. You install cri-dockerd, the shim that lets the kubelet use Docker as a container runtime, then enable its service, then set the kernel parameters Kubernetes networking depends on and load them without a reboot.
