Lab 3.2 Creating deployment on Master

I can think of 2 reasons to run kubectl on the master instead of the worker:

1. kube-apiserver only runs on the master. If you run kubectl "somewhere else" (such as from the worker node), kubectl must connect to the master ip and port. In the case of this lab, the authors can always be sure that kubectl executed on the master will be able to reach kube-apiserver running on the master. If you run kubectl somewhere else, there's a chance some infrastructure config could block access to kube-apiserver.
2. kubectl needs to authenticate to kube-apiserver. The k8smaster.sh setup process creates the ~/.kube/config file that kubectl uses to authenticate.

You could copy ~/.kube/config to your worker node

lets try it, on worker node, 'kubectl get pods' fails because I have not copied over the .kube/config file

root@node1:~# kubectl get pods
The connection to the server localhost:8080 was refused - did you specify the right host or port?

I then copied ~/.kube/config from the master node to the worker. now the kubectl command works

root@node1:~# kubectl get nodes
NAME    STATUS   ROLES    AGE     VERSION
node1   Ready    <none>   5d21h   v1.16.1
node2   Ready    master   5d22h   v1.16.1