Kubernetes Part II - Installation on CentOS 7

Initially, I started to follow some instructions on installing Kubernetes that someone sent to me in an email.

I had trouble with those, so naturally I went looking for others, and then proceeded to use these at this link:

https://www.howtoforge.com/tutorial/centos-kubernetes-docker-cluster/

These seemed to work for the most part, but I kept noticing that all of the DNS was failing. I was convinced it was an issue with these particular instructions.

At wits end, I finally wound up using Yogesh Mehta's instructions on creating a cluster.

https://www.youtube.com/watch?v=lTyKeNRopqY&t=82s

The youtube process which Yogesh covers is a bit different than what you see in this link I provided above. But one of the things I learned in following Yogesh's instructions, was that I had inadvertently put the entries in the hosts file backwards on all three nodes. In other words I put the hostname in first followed by the IP. This was "caught" with Yogesh's process because he has a sensible step to ping each node by hostname. 

But this I can tell you - this is an easy to make mistake, and you can pull your hair out trying to understand what the issue is because when you pull up 3 hosts files that all look like and have entries in them, it's not obvious that the order is wrong!

In the end, I was able to get a Master and two Nodes (or Workers, or Minions or whatever they catchphrase of the day is) up and running.

Now the Master, it could not run "kubectl get nodes". This is because the instructions from Yogesh do not make it clear that the "kubectl config" commands that he covers in his last step apply to the Master (his text states that these commands are only run on nodes, and not the "Master"). But when I ran these commands on the Master, the Master could run the "kubectl get nodes" command and get a proper status.

NOTE: It is worth mentioning also that the Master does NOT need to run kubelet; yet many instructions I saw had kubelet being installed on the master.

So far so good. I have a working Master and two Nodes (workers)....