Kubernetes Vagrant

This repository includes steps for setting up Kubernetes on an Ubuntu machine using Vagrant. I basically wanted my own development cluster, but had only invested in a single server (womp womp)! To solve this problem.... virtual machines to the rescue! It is based on assets from mbaykara/k8s-cluster and this article.

Steps

0. Clone the repository

$ git clone https://github.com/vsoch/k8s-vagrant

1. Install Dependencies

We need vagrant and virtual box

$ sudo apt-get update
$ sudo apt-get install -v vagrant virtualbox

2. Vagrant up

Then bring up the cluster!

$ vagrant up

3. Nodes

We will next want to ssh in to our main and worker nodes.

main

$ vagrant ssh main

kubeadm ("Kube Admin") is installed, and you can use it to initialize the main node.

$ which kubeadm
/usr/bin/kubeadm
vagrant@main:~$ sudo kubeadm init --apiserver-advertise-address 192.168.33.13 --pod-network-cidr=10.244.0.0/16
[init] Using Kubernetes version: v1.23.1
[preflight] Running pre-flight checks
[preflight] Pulling images required for setting up a Kubernetes cluster
[preflight] This might take a minute or two, depending on the speed of your internet connection
[preflight] You can also perform this action in beforehand using 'kubeadm config images pull'
...

Then you can join any number of worker nodes by running the following on each as root:

kubeadm join 192.168.33.13:6443 --token xxxxxxxxxxxxxxxxxxxx \
	--discovery-token-ca-cert-hash xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx

When it is finished (you see the last line above) you'll want to setup your local kube config file. If you've ever connected to an already running cluster, you likely used this:

$ mkdir -p $HOME/.kube
$ sudo cp -i /etc/kubernetes/admin.conf $HOME/.kube/config
$ sudo chown $(id -u):$(id -g) $HOME/.kube/config

You can try this, and see that nodes aren't ready:

$ kubectl get nodes
NAME   STATUS     ROLES                  AGE     VERSION
main   NotReady   control-plane,master   7m23s   v1.23.1

todo going to try calico here instead

Apply the networking policy:

$ kubectl apply -f https://raw.githubusercontent.com/vsoch/k8s-vagrant/main/k8s/network/kube-flannel.yml
Warning: policy/v1beta1 PodSecurityPolicy is deprecated in v1.21+, unavailable in v1.25+
podsecuritypolicy.policy/psp.flannel.unprivileged created
clusterrole.rbac.authorization.k8s.io/flannel created
clusterrolebinding.rbac.authorization.k8s.io/flannel created
serviceaccount/flannel created
configmap/kube-flannel-cfg created
daemonset.apps/kube-flannel-ds created

If you see nodes are unhealthy, follow instructions in this post. Mine were healthy :)

$ kubectl get cs

Then exit back to your local machine.

workers

For each worker, do:

# Example to connect to each one
$ vagrant ssh worker-1
$ vagrant ssh worker-2

Note that this particular hash and token you'll need to copy from the main node output (the last line we saw above).

$ sudo kubeadm join 192.168.33.13:6443 --token xxxxxxxxxxxxxxxxxxxxxxxxxxx \
    --discovery-token-ca-cert-hash xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx

Then go back to the main node, and check your cluster again:

$ kubectl get nodes
NAME       STATUS   ROLES                  AGE     VERSION
main       Ready    control-plane,master   10m     v1.23.1
worker-1   Ready    <none>                 3m11s   v1.23.1
worker-2   Ready    <none>                 102s    v1.23.1

Now create a test deployment.

$ kubectl create deployment nginx --image=nginx --port 80

To access from the internet we have to expose it as follow
$ kubectl expose deployment nginx --port 80 --type=NodePort

And then get the port address (it will be available from the worker nodes address in /etc/hosts)

$ kubectl describe services nginx
Name:                     nginx
Namespace:                default
Labels:                   app=nginx
Annotations:              <none>
Selector:                 app=nginx
Type:                     NodePort
IP Family Policy:         SingleStack
IP Families:              IPv4
IP:                       10.111.17.161
IPs:                      10.111.17.161
Port:                     <unset>  80/TCP
TargetPort:               80/TCP
NodePort:                 <unset>  31412/TCP  <----
Endpoints:                10.244.1.2:80
Session Affinity:         None
External Traffic Policy:  Cluster
Events:                   <none>

And get it!

$ curl http://192.168.33.14:31412
<!DOCTYPE html>
<html>
<head>
<title>Welcome to nginx!</title>
<style>
html { color-scheme: light dark; }
body { width: 35em; margin: 0 auto;
font-family: Tahoma, Verdana, Arial, sans-serif; }
</style>
</head>
<body>
<h1>Welcome to nginx!</h1>
<p>If you see this page, the nginx web server is successfully installed and
working. Further configuration is required.</p>

<p>For online documentation and support please refer to
<a href="http://nginx.org/">nginx.org</a>.<br/>
Commercial support is available at
<a href="http://nginx.com/">nginx.com</a>.</p>

<p><em>Thank you for using nginx.</em></p>
</body>
</html>