3 - Setting up Kubernetes

3.1 - Install Prerequisites

1. Switch to root: sudo -i
2. Load modules for next steps:

modprobe overlay
modprobe br_netfilter

3. Update kernel networking to allow necessary traffic:

cat << EOF | tee /etc/sysctl.d/kubernetes.conf
net.bridge.bridge-nf-call-ip6tables = 1
net.bridge.bridge-nf-call-iptables = 1
net.ipv4.ip_forward = 1
EOF

4. Install necessary key for containerd:

mkdir -p /etc/apt/keyrings
curl -fsSL https://download.docker.com/linux/ubuntu/gpg | sudo gpg --dearmor -o /etc/apt/keyrings/docker.gpg
echo "deb [arch=$(dpkg --print-architecture) signed-by=/etc/apt/keyrings/docker.gpg] https://download.docker.com/linux/ubuntu $(lsb_release -cs) stable" | sudo tee /etc/apt/sources.list.d/docker.list > /dev/null

5. Install containerd:

apt-get update && apt-get install containerd.io -y
containerd config default | tee /etc/containerd/config.toml
sed -e 's/SystemdCgroup = false/SystemdCgroup = true/g' -i /etc/containerd/config.toml
systemctl restart containerd

6. Add repo for Kubernetes and then install it (Might be outdated):

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
curl -fsSL https://pkgs.k8s.io/core:/stable:/v1.30/deb/Release.key | sudo gpg --dearmor -o /etc/apt/keyrings/kubernetes-apt-keyring.gpg
apt-get update && apt-get install -y kubeadm=1.30.1-00 kubelet=1.30.1-00 kubectl=1.30.1-00
apt-mark hold kubelet kubeadm kubectl

7. Add the host IP address in the hosts file and tie it to k8scp: nano /etc/hosts

3.2 - Initialize the Cluster

Must be logged into root account:

1. Set up the kubeadm initialization script (Might be outdated): nano kubeadm-config.yaml

apiVersion: kubeadm.k8s.io/v1beta3
kind: ClusterConfiguration
networking:
  serviceSubnet: "10.96.0.0/12" # Default range for services
  podSubnet: "10.244.0.0/16" # Custom range for Calico; ensure it doesn't conflict with your network
  dnsDomain: "cluster.local" # Default DNS domain; change if you have a specific need
controlPlaneEndpoint: "k8scp:6443" # Your control plane endpoint; matches your hosts file configuration
apiServer:
  extraArgs:
    advertise-address: "<Primary Node IP>" # Replace with your control plane's static IP
    allow-privileged: "true"
controllerManager:
  extraArgs: {}
scheduler:
  extraArgs: {}
kubeletConfiguration:
  baseConfig:
    resolvConf: "/run/systemd/resolve/resolv.conf"
---
apiVersion: kubeproxy.config.k8s.io/v1alpha1
kind: KubeProxyConfiguration
mode: "ipvs"

2. Need to enable ipv4 forwarding: echo 1 > /proc/sys/net/ipv4/ip_forward
3. Initiate the Kubernetes cl;uster: kubeadm init --config=kubeadm-config.yaml --upload-certs | tee kubeadm-init.out
4. Exit root user and configure the node for the standard user account:

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

5. Install Helm:

curl https://baltocdn.com/helm/signing.asc | gpg --dearmor | sudo tee /usr/share/keyrings/helm.gpg > /dev/null
sudo apt-get install apt-transport-https --yes
echo "deb [arch=$(dpkg --print-architecture) signed-by=/usr/share/keyrings/helm.gpg] https://baltocdn.com/helm/stable/debian/ all main" | sudo tee /etc/apt/sources.list.d/helm-stable-debian.list
sudo apt-get update && sudo apt-get install helm

3.3 - Join a Node to the Cluster

3.3.1 - Control Plane Setup

Must be logged into root account:

1. Need to enable ipv4 forwarding: echo 1 > /proc/sys/net/ipv4/ip_forward
2. Initiate the Kubernetes node:

kubeadm join k8scp:6443 --token <token> /
--discovery-token-ca-cert-hash sha256:<token sha256 hash> /
--control-plane /
--certificate-key <certificate key> | tee kubeadm-join.out

3. Exit root user and configure the node for the standard user account:

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

4. (Optional) Remove taints from the node to allow scheduling workloads:

kubectl taint nodes <hostname> node-role.kubernetes.io/control-plane:NoSchedule-

5. (Optional) Install Helm:

curl https://baltocdn.com/helm/signing.asc | gpg --dearmor | sudo tee /usr/share/keyrings/helm.gpg > /dev/null
sudo apt-get install apt-transport-https --yes
echo "deb [arch=$(dpkg --print-architecture) signed-by=/usr/share/keyrings/helm.gpg] https://baltocdn.com/helm/stable/debian/ all main" | sudo tee /etc/apt/sources.list.d/helm-stable-debian.list
sudo apt-get update && sudo apt-get install helm

3.3.2 - Worker Node Setup

Must be logged into root account: Need to enable ipv4 forwarding: echo 1 > /proc/sys/net/ipv4/ip_forward

kubeadm join k8scp:6443 --token <token> /
--discovery-token-ca-cert-hash sha256:<token sha256 hash> /
--certificate-key <certificate key> | tee kubeadm-join.out