Setting Up K8s cluster on your machine

FYI: Please check this link for the system requirements for the setup

My personal recommendation would be to use a linux machine with 4 GB of RAM and 2+ cpus for the control plane and 2GB or 4GB of RAM and 1 cpu for the worker nodes.

I am using flannel network for setting up the cluster locally so please follow for below steps:

Disable the swap and comment the line on /etc/fstab please check this for more info

sudo swapoff -a
sudo sed -i '/ swap / s/^/#/' /etc/fstab

Configure containerd (skip this next two code blocks step if you have already installed docker following the official documentation)

sudo apt update
sudo apt install -y containerd

sudo mkdir -p /etc/containerd
containerd config default | sudo tee /etc/containerd/config.toml

Update the config.toml to set systemd as cgroup driver (continue from here if you already have docker and containerd installed)

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

Let us configure the network and storage modules on the linux kernel

sudo modprobe overlay
sudo modprobe br_netfilter

To persist on reboot:

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

cat <<EOF | sudo tee /etc/sysctl.d/k8s.conf
net.ipv4.ip_forward                 = 1
EOF

sudo sysctl --system

The above commands are required for enabling the overlayfs (union FS) on the linux kernel for storage and memory sharing for the containers. br_netfilter is required for enabling the networking between pods and across multiple nodes.

Finally run the next two commands

sudo systemctl restart containerd
sudo systemctl enable containerd

Now let us install kubeadm, kubectl and kubelet

sudo apt update -y
sudo apt install -y apt-transport-https ca-certificates curl
curl -fsSL https://packages.cloud.google.com/apt/doc/apt-key.gpg | sudo gpg --dearmor -o /usr/share/keyrings/kubernetes-archive-keyring.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 update -y
sudo apt install -y kubelet kubeadm kubectl

Initailize the cluster with the following commands (read this for using 10.244.0.0/16) and you should see the something similar to the screenshots attached belows

sudo kubeadm init --pod-network-cidr=10.244.0.0/16

Run the commands below to work with k8s using a user account:

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

Run the next command to setup the flannel network:

kubectl apply -f https://github.com/flannel-io/flannel/releases/latest/download/kube-flannel.yml

Then execute kubectl get pods -A to get the list of running pods

To add the worker nodes to the control plane execute the following command(this command will be available once kubeadm has initialized successfully check the 2nd screenshot for reference) on all available nodes :

sudo kubeadm join <control-plane-ip>:6443 --token <token> --discovery-token-ca-cert-hash sha256:<hash>

On control plane node run kubectl get nodes to check if the nodes are associated.

Cleanup

For resetting the whole setup execute the below commands on the appropriate nodes

# run this first only on worker nodes then proceed to the next command
kubectl delete node <worker-node-name>
# on control plane and on worker nodes
sudo kubeadm reset -f