There are two versions of this script - one to use docker, which is 9a, and the other to use containerd, which is 9b.

The 9a (docker) variant does not setup the untrusted runtime environment using runsc and gVisor. However, docker is easier and more straightforward to deploy on CentOS via yum.

This script installs Kubernetes on the nodes designated as worker nodes.

The script reads the KUBE_POD_ADDR (this is pod specific) and KUBE_NODE_POD_PREFIX environment variables and copies these to each workder node.

The script then copies the kubelet setup script to each worker node, and then executes via sudo the script on each node.

The node setup script installs and enables docker on each node, and then installs kubelet from the Kubernetes repository. Currently this is installing 1.10.3 - action item for the future is to use an updated version, or make the version configurable via an environment variable.

The container networking configuraation is provided in /etc/cni - this uses the variables previously copied across.

The kubelet is downloaded and the correct configuration applied from the environment variables.

The kubelet service is then enabled and started.