Kubernetes cluster installation guide

1 - Getting the server ready

sudo apt-get update
sudo apt-get install -y apt-transport-https ca-certificates curl gpg
sudo mkdir -p /etc/apt/keyrings
curl -fsSL https://pkgs.k8s.io/core:/stable:/v1.32/deb/Release.key | sudo gpg --dearmor -o /etc/apt/keyrings/kubernetes-apt-keyring.gpg
echo 'deb [signed-by=/etc/apt/keyrings/kubernetes-apt-keyring.gpg] https://pkgs.k8s.io/core:/stable:/v1.32/deb/ /' | sudo tee /etc/apt/sources.list.d/kubernetes.list
sudo apt update
sudo apt install -y kubelet kubeadm kubectl
sudo apt-mark hold kubelet kubeadm kubectl

2 - Disable swap memory

sudo swapoff -a
sudo sed -i '/swap.img/ s/^\(.*\)$/#\1/g' /etc/fstab
sudo sed -i '/swap/ s/^\(.*\)$/#\1/g' /etc/fstab

3 - Configure network and modules

3.1 Configure persistent loading of modules

sudo tee /etc/modules-load.d/containerd.conf <<EOF
overlay
br_netfilter
EOF

3.2 Load at runtime

sudo modprobe overlay
sudo modprobe br_netfilter

3.3 Ensure sysctl params are set

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

3.4 Reload configs

sudo sysctl --system

4 - Install and configure Containerd

4.1 Add docker repository

sudo curl -fsSL https://download.docker.com/linux/ubuntu/gpg -o /etc/apt/keyrings/docker.asc
sudo chmod a+r /etc/apt/keyrings/docker.asc
echo "deb [arch=$(dpkg --print-architecture) signed-by=/etc/apt/keyrings/docker.asc] https://download.docker.com/linux/ubuntu $(. /etc/os-release && echo "$VERSION_CODENAME") stable" | sudo tee /etc/apt/sources.list.d/docker.list > /dev/null

4.2 Install containerd

sudo apt update
sudo apt install -y containerd.io

4.3 Configure containerd

sudo containerd config default | sudo tee /etc/containerd/config.toml
sudo sed -i 's/SystemdCgroup = false/SystemdCgroup = true/' /etc/containerd/config.toml

4.4 Start/restart containerd

sudo systemctl restart containerd
sudo systemctl enable containerd

5 - Master node configuration

5.1 Enable and start kubelet

sudo systemctl enable kubelet
sudo kubeadm config images pull
sudo kubeadm init --pod-network-cidr=192.168.0.0/16

_{Note: If 192.168.0.0/16 is already in use within your network you must select a different pod network CIDR, replacing 192.168.0.0/16 in the above command.}

Other options of the init command, but we are not going to use right now are:

--cri-socket ==> Use if have more than one container runtime to set runtime socket path
--apiserver-advertise-address ==> Set advertise address for this particular control-plane node's API server

If everything is ok, you will able to read a message saying "Your Kubernetes control-plane has initialized successfully!". If so, you need to run the following:

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

6 - Installing Calico

6.1 Installing Calico

kubectl apply -f https://raw.githubusercontent.com/projectcalico/calico/v3.28.0/manifests/calico.yaml
kubectl get nodes

6.2 Check kubernetes nodes

kubectl get nodes

7 - Joining other nodes

7.1 For joining other nodes execute the following command

sudo kubeadm token create --print-join-command

7.2 Example of join token

kubeadm join 192.168.122.40:6443 --token r705ed.7d47ya6a6f3eecr4 --discovery-token-ca-cert-hash sha256:0c740869ea8a0e833a0163c5246fb74daed12baf7207e8a4a7f37dda40aaee4e

8 - Untaint master node

8.1 Check node name

kubectl get nodes

NAME                                   STATUS   ROLES           AGE   VERSION
soffid-ubuntu-24-04-pc-q35-ich9-2009   Ready    control-plane   15m   v1.32.13

8.2 Enable the master node to execute pods

kubectl taint node NODE_NAME node-role.kubernetes.io/master:NoSchedule-

-Example-
kubectl taint node soffid-ubuntu-24-04-pc-q35-ich9-2009 node-role.kubernetes.io/control-plane:NoSchedule-

8.3 Check master node taints

kubectl describe node NODE_NAME | grep Taints

-Example-
kubectl describe node soffid-ubuntu-24-04-pc-q35-ich9-2009 | grep Taints