worker cluster

The worker cluster configuration steps are very similar to the control-panel cluster.

Step 1: Prepare the System

• Configure kernel modules by creating a configuration file:

cat <<EOF | sudo tee /etc/modules-load.d/k8s.conf
overlay
br_netfilter
EOF

Load the required kernel modules:

sudo modprobe overlay
sudo modprobe br_netfilter
sudo sysctl --system

Step 2: Install Container Runtimes

• Add Docker's official GPG key:

sudo apt-get update
sudo apt-get install ca-certificates curl gnupg
sudo install -m 0755 -d /etc/apt/keyrings
curl -fsSL https://download.docker.com/linux/ubuntu/gpg | sudo gpg --dearmor -o /etc/apt/keyrings/docker.gpg
sudo chmod a+r /etc/apt/keyrings/docker.gpg

Add the Docker repository to Apt sources:

echo \
  "deb [arch=\$(dpkg --print-architecture) signed-by=/etc/apt/keyrings/docker.gpg] https://download.docker.com/linux/ubuntu \
  \$(. /etc/os-release && echo "\$VERSION_CODENAME") stable" | \
  sudo tee /etc/apt/sources.list.d/docker.list > /dev/null
sudo apt-get update

Install containerd.io:

sudo apt-get install containerd.io

Step 3: Install Container Networking Plugins

• Download and install CNI plugins:

wget https://github.com/containernetworking/plugins/releases/download/v1.3.0/cni-plugins-linux-amd64-v1.3.0.tgz
mkdir -p /opt/cni/bin
tar -C /opt/cni/bin -xzvf cni-plugins-linux-amd64-v1.3.0.tgz

Edit the containerd configuration:

nano /etc/containerd/config.toml

Add the following configuration under

[plugins."io.containerd.grpc.v1.cri".containerd.runtimes.runc.options]
SystemdCgroup = true

You need CRI support enabled to use containerd with Kubernetes. Make sure that cri is not included in thedisabled_plugins list within /etc/containerd/config.toml;

Restart containerd:

sudo systemctl restart containerd

Step 4: Install Kubernetes Tools

• Install necessary tools and set up the Kubernetes repository:

sudo apt-get update
sudo apt-get install -y apt-transport-https ca-certificates curl

sudo curl -fsSLo /usr/share/keyrings/kubernetes-archive-keyring.gpg https://packages.cloud.google.com/apt/doc/apt-key.gpg

echo "deb [signed-by=/usr/share/keyrings/kubernetes-archive-keyring.gpg] https://apt.kubernetes.io/ kubernetes-xenial main" | sudo tee /etc/apt/sources.list.d/kubernetes.list
sudo apt-get update

List available versions of kubeadm:

sudo apt list -a kubeadm

Install kubeadm, kubelet, and kubectl (replace 1.28.0 with your desired version):

sudo apt-get install kubeadm=1.28.0-00
sudo apt-get install kubelet=1.28.0-00

After completing this process, you now have your worker cluster installed.

Connecting cluster worker with cluster control-plane:

• Access your control pane cluster and create the token to connect your worker cluster.

sudo kubeadm token create --print-join-command

A token will be generated see below for an example

kubeadm join 111.231.252.43:6443 --token 17htao.wo5w0fn1rpg21e9m --discovery-token-ca-cert-hash sha256:ea9a3611d926cf9a7cfadb089a0d47500f89bab1g5ef45310b9a8d82a65c48b

Now just copy the generated token into your cluster worker and the connection will be established. Once this is done, when consulting your node you will see the connection successfully.