Run "desktop" Kubernetes via Rancher 'k3s '

References

• Rancher 'k3s', streamlined Kubernetes for IoT / Edge: https://github.com/rancher/k3s

• A very well-documented Virtualbox "box" for Ubuntu: https://app.vagrantup.com/peru/boxes/ubuntu-18.04-server-amd64

• Vagrantfile for Openstack: https://github.com/OpenStackCookbook/vagrant-openstack.git

• Vagrantfile for kubespray (Ansible playbooks for K8S installations): https://github.com/kubernetes-sigs/kubespray/blob/master/Vagrantfile

Setting up K8S in Vagrant / Virtualbox "nodes"

Install Vagrant

Fetch and install the v2.2.6 version of Vagrant. Browse to https://www.vagrantup.com/downloads.html.

wget https://releases.hashicorp.com/vagrant/2.2.6/vagrant_2.2.6_x86_64.deb

sudo apt-get -y install vagrant_2.2.6_x86_64.deb

Install Virtualbox for Ubuntu 18.x

The "to-date" (2.2.6, current) version of Vagrant, requires Oracle Virtualbox v6.1.0:

vagrant --version
  Vagrant 2.2.6

wget  https://download.virtualbox.org/virtualbox/6.1.0/virtualbox-6.1_6.1.0-135406~Ubuntu~eoan_amd64.deb

sudo apt-get -y install  virtualbox-6.1.6.1.0-135406~Ubuntu~eoan_amd64.deb 

It may be necessary to "reconfigure" the DKMS module and "vbox" kernel modules, for Virtualbox. In particular, do this after an Ubuntu kernel update:

sudo dpkg-reconfigure virtualbox-dkms
sudo dpkg-reconfigure virtualbox

sudo modprobe vboxdrv
sudo modprobe vboxnetflt

Repair and configure Vagrant installation

A new version of Vagrant often requires Vagrant plugins to be either repaired or updated. This project's Vagrant file also needs the hostmanager and cachier plugins.

vagrant plugin repair
vagrant plugin update

vagrant plugin install vagrant-hostmanager
vagrant plugin install vagrant-cachier

Get the VM Virtualbox image

alias vg=vagrant

# download the box-image
vg box add peru/ubuntu-18.04-server-amd64

Launch & install a K3s master and node(s)

Using the Vagrantfile in this project, just run vagrant up. It will install Rancher 'k3s' and provision as needed, for Master and worker Nodes.

Install the K8S Dashboard "app"

Official Kubernetes README for the Dashboard: https://github.com/kubernetes/dashboard/blob/master/README.md

Configure kubectl, and test

First, set-up configuration for kubectl to work with the K8S/k3s Master node. The k3s.yaml config-file is created during Master-node provisioning. See this project's Vagrantfile.

export KUBECONFIG=$PWD/k3s.yaml

kubectl get pods -A  # list Pods in 'kube-system' namespace

Create the K8S Dashboard admin-user

Create the Dashboard admin-user, via a dashboard-admin.yaml file. Use a dashboard-admin.yaml file with kubectl to create this user. Reference: https://github.com/kubernetes/dashboard/blob/master/docs/user/access-control/creating-sample-user.md#creating-sample-user

kubectl apply -f dashboard-admin.yaml

  - serviceaccount/admin-user created
  - clusterrolebinding.rbac.authorization.k8s.io/admin-user created

Download, install & run the K8S Dashboard

kubectl apply -f https://raw.githubusercontent.com/kubernetes/dashboard/v2.0.0-rc2/aio/deploy/recommended.yaml

# "download" the secret/token, for logging into the Dashboard
kubectl -n kube-system describe secret $(kubectl -n kube-system get secret | grep admin-user | awk '{print $1}') > .ksekret

# start the proxy
pkill -f proxy
kubectl proxy &

# browse-to the Dashboard, login with "token" in '.ksekret'
xdg-open http://localhost:8001/api/v1/namespaces/kubernetes-dashboard/services/https:kubernetes-dashboard:/proxy/

Trials of Kubernetes / Rancher 'k3s'

kubectl information commands

kubectl cluster-info

  Kubernetes master is running at https://10.96.48.17:6443
  CoreDNS is running at https://10.96.48.17:6443/api/v1/namespaces/kube-system/services/kube-dns:dns/proxy
  Metrics-server is running at https://10.96.48.17:6443/api/v1/namespaces/kube-system/services/https:metrics-server:/proxy

  To further debug and diagnose cluster problems, use 'kubectl cluster-info dump'.

kubectl get pods -A -o wide  # all "namespaces", all Pods

kubectl get deployments -A -o wide  # deployment(s) details

kubectl get services -A -o wide

kubectl api-resources

hello-minikube app, deploy & test

kubectl create deployment hello-node --image=gcr.io/hello-minikube-zero-install/hello-node

kubectl get deployments  # wait for it... 'ContainerCreating => Running
kubectl get pods
kubectl get events

# cleaning up 'hello-minikube'
kubectl delete services hello-minikube
kubectl delete deployment hello-minikube

kubectl get events

# kubectl expose deployment hello-minikube --type=NodePort --port=8080