First of all, we need to log in to one of our three Droplets; the first machine we log into will be our Kubernetes master:
$ ssh firstname.lastname@example.org
Once logged in, the following two commands check for any updates to the packages and apply them:
$ apt-get update$ apt-get upgrade
Now that we are up-to-date we can install the prerequisite packages. To do this run the following:
$ apt-get install docker.io curl apt-transport-https
You may notice that we are using the version of Docker that is distributed as part of the core Ubuntu 16.04 package repositories rather than the official Docker release. This is because kubeadm doesn't have official support for newer versions of Docker and the recommended version ...