vagrant kubeadm testing

This Vagrantfile provisions a 4cpu/4GB Ubuntu 17.10 vm for the purpose of developing on kubeadm.
Recent packages of kubernetes components will be installed and a compatible Docker daemon is started and running.
The bashrc is configured by default to use /etc/kubernetes/admin.conf.
An upstream version of kubeadm is installed for reference usage.

copy_kubeadm_bin.sh takes your built kubeadm binary, prefixes it with an issue number and copies it into this repo's ./bin, so that it may be used from /vagrant/bin inside the VM for testing.
This is useful for comparing builds.

example

build two versions of kubeadm:

cd ~/go/src/k8s.io/kubernetes

git checkout feature/kubeadm_594-etcd_tls
bazel test //cmd/kubeadm/...
bazel build //cmd/kubeadm --platforms=@io_bazel_rules_go//go/toolchain:linux_amd64
issue=594 ~/Repos/vagrant-kubeadm-testing/copy_kubeadm_bin.sh

git checkout feature/kubeadm_710-etcd-ca
bazel test //cmd/kubeadm/...
bazel build //cmd/kubeadm --platforms=@io_bazel_rules_go//go/toolchain:linux_amd64
issue=710 ~/Repos/vagrant-kubeadm-testing/copy_kubeadm_bin.sh

experiment with the two builds on the vagrant:

cd ~/Repos/vagrant-kubeadm-testing

vagrant up
vagrant ssh
  sudo /vagrant/bin/594_kubeadm init
  sudo /vagrant/bin/594_kubeadm reset
  sudo /vagrant/bin/710_kubeadm init