Install Kubernetes

# Switch to the root user
sudo -i 

# Add required kernel modules to the configuration for loading at boot
printf "overlay\nbr_netfilter\n" >> /etc/modules-load.d/containerd.conf

# Load the kernel modules immediately
modprobe overlay
modprobe br_netfilter

# Configure sysctl parameters required for Kubernetes networking
printf "net.bridge.bridge-nf-call-iptables = 1\nnet.ipv4.ip_forward = 1\nnet.bridge.bridge-nf-call-ip6tables = 1\n" >> /etc/sysctl.d/99-kubernetes-cri.conf

# Apply the sysctl parameters without rebooting
sysctl --system

# Download the specified version of containerd
wget https://github.com/containerd/containerd/releases/download/v1.7.14/containerd-1.7.14-linux-amd64.tar.gz -P /tmp

# Extract the downloaded containerd archive to /usr/local
tar Cxzvf /usr/local /tmp/containerd-1.7.14-linux-amd64.tar.gz

# Download the systemd service file for containerd
wget https://raw.githubusercontent.com/containerd/containerd/main/containerd.service -P /etc/systemd/system/

# Reload systemd configuration and enable containerd to start on boot, then start it immediately
systemctl daemon-reload
systemctl enable --now containerd

# Download the runc binary
wget https://github.com/opencontainers/runc/releases/download/v1.1.13/runc.amd64 -P /tmp/

# Install the runc binary to /usr/local/sbin with appropriate permissions
install -m 755 /tmp/runc.amd64 /usr/local/sbin/runc

# Download the CNI plugins archive
wget https://github.com/containernetworking/plugins/releases/download/v1.5.1/cni-plugins-linux-amd64-v1.5.1.tgz -P /tmp/

# Create the directory for CNI plugins and extract the downloaded archive there
mkdir -p /opt/cni/bin
tar Cxzvf /opt/cni/bin /tmp/cni-plugins-linux-amd64-v1.5.1.tgz

# Create the containerd configuration directory
mkdir -p /etc/containerd

# Generate the default containerd configuration and save it to the config file
containerd config default | tee /etc/containerd/config.toml

# Ensure that swap is turned off
swapoff -a

# Edit /etc/fstab and comment out any line that refers to swap
# This can be done manually using a text editor like nano or vim
# For example: nano /etc/fstab

# Update package lists and install required packages
apt update && sudo apt install -y apt-transport-https ca-certificates curl gpg

# Create the directory for storing apt keyrings with appropriate permissions
mkdir -p -m 755 /etc/apt/keyrings

# Download and store the Kubernetes APT repository key
curl -fsSL https://pkgs.k8s.io/core:/stable:/v1.30/deb/Release.key | sudo gpg --dearmor -o /etc/apt/keyrings/kubernetes-apt-keyring.gpg

# Add the Kubernetes APT repository to the sources list
echo 'deb [signed-by=/etc/apt/keyrings/kubernetes-apt-keyring.gpg] https://pkgs.k8s.io/core:/stable:/v1.30/deb/ /' | sudo tee /etc/apt/sources.list.d/kubernetes.list

# Update package lists again to include the Kubernetes repository
apt update

# Reboot the system to apply changes
reboot

# Switch to the root user
sudo -i

# Install specific versions of kubelet, kubeadm, and kubectl
apt install -y kubelet=1.30.2-1.1 kubeadm=1.30.2-1.1 kubectl=1.30.2-1.1

# Prevent the installed versions of kubelet, kubeadm, and kubectl from being automatically updated
apt-mark hold kubelet kubeadm kubectl

kubeadm init --pod-network-cidr 10.10.0.0/16 --kubernetes-version 1.30.2 --node-name k8s-ctrlr
export KUBECONFIG=/etc/kubernetes/admin.conf

# For non-root user run the following commands
mkdir -p $HOME/.kube
sudo cp -i /etc/kubernetes/admin.conf $HOME/.kube/config
sudo chown $(id -u):$(id -g) $HOME/.kube/config

# Setup Calico CNI 3.28.0
kubectl create -f https://raw.githubusercontent.com/projectcalico/calico/v3.28.0/manifests/tigera-operator.yaml
wget https://raw.githubusercontent.com/projectcalico/calico/v3.28.0/manifests/custom-resources.yaml

# This section includes base Calico installation configuration.
# For more information, see: https://docs.tigera.io/calico/latest/reference/installation/api#operator.tigera.io/v1.Installation
apiVersion: operator.tigera.io/v1
kind: Installation
metadata:
  name: default
spec:
  # Configures Calico networking.
  calicoNetwork:
    ipPools:
    - name: default-ipv4-ippool
      blockSize: 26
      cidr: 10.10.0.0/16
      encapsulation: VXLANCrossSubnet
      natOutgoing: Enabled
      nodeSelector: all()

---

# This section configures the Calico API server.
# For more information, see: https://docs.tigera.io/calico/latest/reference/installation/api#operator.tigera.io/v1.APIServer
apiVersion: operator.tigera.io/v1
kind: APIServer
metadata:
  name: default
spec: {}

kubeadm token create --print-join-command

apiVersion: v1
kind: Pod
metadata:
  name: nginx-example
  labels:
    app: nginx
spec:
  containers:
    - name: nginx
      image: linuxserver/nginx
      ports:
        - containerPort: 80
          name: "nginx-http"

david@k8s-ctrlr:~$ kubectl apply -f pod.yml
pod/nginx-example created

# Check to see that the Pod has been created
david@k8s-ctrlr:~ kubectl get pods
NAME            READY   STATUS    RESTARTS   AGE
nginx-example   1/1     Running   0          85s

# View more details
david@k8s-ctrlr:~$ kubectl get pods -o wide
NAME            READY   STATUS    RESTARTS   AGE     IP             NODE         NOMINATED NODE   READINESS GATES
nginx-example   1/1     Running   0          9m57s   10.10.109.66   k8s-node-1   <none>           <none>

david@k8s-ctrlr:~$ curl 10.10.109.66
    <html>
        <head>
            <title>Welcome to our server</title>
            <style>
            body{
                font-family: Helvetica, Arial, sans-serif;
            }
            .message{
                width:330px;
                padding:20px 40px;
                margin:0 auto;
                background-color:#f9f9f9;
                border:1px solid #ddd;
            }
            center{
                margin:40px 0;
            }
            h1{
                font-size: 18px;
                line-height: 26px;
            }
            p{
                font-size: 12px;
            }
            </style>
        </head>
        <body>
            <div class="message">
                <h1>Welcome to our server</h1>
                <p>The website is currently being setup under this address.</p>
                <p>For help and support, please contact: <a href="me@example.com">me@example.com</a></p>
            </div>
        </body>
    </html>

apiVersion: v1
kind: Service
metadata:
  name: nginx-example
spec:
  type: NodePort
  ports:
    - name: http
      port: 80
      nodePort: 30080
      targetPort: nginx-http
  selector:
    app: nginx

david@k8s-ctrlr:~$ kubectl apply -f service-nodeport.yml
service/nginx-example created

# Check that the service is online
david@k8s-ctrlr:~$ kubectl get service
NAME            TYPE        CLUSTER-IP      EXTERNAL-IP   PORT(S)        AGE
kubernetes      ClusterIP   10.96.0.1       <none>        443/TCP        27h
nginx-example   NodePort    10.101.177.98   <none>        80:30080/TCP   11s

❯ curl http://192.168.8.81:30080/
    <html>
        <head>
            <title>Welcome to our server</title>
            <style>
            body{
                font-family: Helvetica, Arial, sans-serif;
            }
            .message{
                width:330px;
                padding:20px 40px;
                margin:0 auto;
                background-color:#f9f9f9;
                border:1px solid #ddd;
            }
            center{
                margin:40px 0;
            }
            h1{
                font-size: 18px;
                line-height: 26px;
            }
            p{
                font-size: 12px;
            }
            </style>
        </head>
        <body>
            <div class="message">
                <h1>Welcome to our server</h1>
                <p>The website is currently being setup under this address.</p>
                <p>For help and support, please contact: <a href="me@example.com">me@example.com</a></p>
            </div>
        </body>
    </html>

# Delete Pod
david@k8s-ctrlr:~$ kubectl delete pod nginx-example
pod "nginx-example" deleted

# Delete Service
david@k8s-ctrlr:~$ kubectl delete service nginx-example
service "nginx-example" deleted