Kubernetes Installation on Ubuntu 22.04

Get the detailed information about the installation from the below-mentioned websites of Docker and Kubernetes.

Set up the Docker and Kubernetes repositories:

Download the GPG key for docker

wget -O - https://download.docker.com/linux/ubuntu/gpg > ./docker.key

gpg --no-default-keyring --keyring ./docker.gpg --import ./docker.key

gpg --no-default-keyring --keyring ./docker.gpg --export > ./docker-archive-keyring.gpg

sudo mv ./docker-archive-keyring.gpg /etc/apt/trusted.gpg.d/

Add the docker repository and install docker

# we can get the latest release versions from https://docs.docker.com

sudo add-apt-repository "deb [arch=amd64] https://download.docker.com/linux/ubuntu $(lsb_release -cs) stable"
sudo apt update
sudo apt install git wget curl -y
sudo apt install -y docker-ce

To install cri-dockerd for Docker support

Docker Engine does not implement the CRI which is a requirement for a container runtime to work with Kubernetes. For that reason, an additional service cri-dockerd has to be installed. cri-dockerd is a project based on the legacy built-in Docker Engine support that was removed from the kubelet in version 1.24.

Get the version details

VER=$(curl -s https://api.github.com/repos/Mirantis/cri-dockerd/releases/latest|grep tag_name | cut -d '"' -f 4|sed 's/v//g')

Run below commands

wget https://github.com/Mirantis/cri-dockerd/releases/download/v${VER}/cri-dockerd-${VER}.amd64.tgz

tar xvf cri-dockerd-${VER}.amd64.tgz

sudo mv cri-dockerd/cri-dockerd /usr/local/bin/

wget https://raw.githubusercontent.com/Mirantis/cri-dockerd/master/packaging/systemd/cri-docker.service

wget https://raw.githubusercontent.com/Mirantis/cri-dockerd/master/packaging/systemd/cri-docker.socket

sudo mv cri-docker.socket cri-docker.service /etc/systemd/system/

sudo sed -i -e 's,/usr/bin/cri-dockerd,/usr/local/bin/cri-dockerd,' /etc/systemd/system/cri-docker.service

sudo systemctl daemon-reload
sudo systemctl enable cri-docker.service
sudo systemctl enable --now cri-docker.socket

Add the GPG key for kubernetes

curl -fsSL https://pkgs.k8s.io/core:/stable:/v1.28/deb/Release.key | sudo gpg --dearmor -o /etc/apt/keyrings/kubernetes-apt-keyring.gpg

Add the kubernetes repository

echo "deb [signed-by=/etc/apt/keyrings/kubernetes-apt-keyring.gpg] https://pkgs.k8s.io/core:/stable:/v1.28/deb/ /" | sudo tee /etc/apt/sources.list.d/kubernetes.list

Update the repository

# Update the repositiries
sudo apt-get update

Install Kubernetes packages.

# Use the same versions to avoid issues with the installation.
sudo apt-get install -y kubelet kubeadm kubectl

To hold the versions so that the versions will not get accidently upgraded.

sudo apt-mark hold docker-ce kubelet kubeadm kubectl

Enable the iptables bridge

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

sudo modprobe overlay
sudo modprobe br_netfilter

# sysctl params required by setup, params persist across reboots
cat <<EOF | sudo tee /etc/sysctl.d/k8s.conf
net.bridge.bridge-nf-call-iptables  = 1
net.bridge.bridge-nf-call-ip6tables = 1
net.ipv4.ip_forward                 = 1
EOF

# Apply sysctl params without reboot
sudo sysctl --system

On the Kube master server

Initialize the cluster by passing the cidr value and the value will depend on the type of network CLI you choose.

Calico

# Calico network
# Make sure to copy the join command
sudo kubeadm init --apiserver-advertise-address=<control_plane_ip> --cri-socket unix:///var/run/cri-dockerd.sock  --pod-network-cidr=192.168.0.0/16

# Use below command if the node network is 192.168.x.x
sudo kubeadm init --apiserver-advertise-address=<control_plane_ip> --cri-socket unix:///var/run/cri-dockerd.sock  --pod-network-cidr=10.244.0.0/16

# Copy your join command and keep it safe.
# Below is a sample format
# Add --cri-socket /var/run/cri-dockerd.sock to the command
kubeadm join <control_plane_ip>:6443 --token 31rvbl.znk703hbelja7qbx --cri-socket unix:///var/run/cri-dockerd.sock --discovery-token-ca-cert-hash sha256:3dd5f401d1c86be4axxxxxxxxxx61ce965f5xxxxxxxxxxf16cb29a89b96c97dd

To start using the cluster with current user.

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

To set up the Calico network

# Use this if you have initialised the cluster with Calico network add on.
kubectl create -f https://raw.githubusercontent.com/projectcalico/calico/v3.25.0/manifests/tigera-operator.yaml

curl https://raw.githubusercontent.com/projectcalico/calico/v3.25.0/manifests/custom-resources.yaml -O

# Change the ip to 10.244.0.0/16 if the node network is 192.168.x.x
kubectl create -f custom-resources.yaml

Check the nodes

# Check the status on the master node.
kubectl get nodes

On each of Kube node server

Joining the node to the cluster:

sudo kubeadm join $controller_private_ip:6443 --token $token --discovery-token-ca-cert-hash $hash
#Ex:
# kubeadm join <control_plane_ip>:6443 --cri-socket unix:///var/run/cri-dockerd.sock --token 31rvbl.znk703hbelja7qbx --discovery-token-ca-cert-hash sha256:3dd5f401d1c86be4axxxxxxxxxx61ce965f5xxxxxxxxxxf16cb29a89b96c97dd

TIP

If the joining code is lost, it can retrieve using below command

kubeadm token create --print-join-command

To install metrics server

git clone https://github.com/mialeevs/kubernetes_installation_docker.git
cd kubernetes_installation_docker/
kubectl apply -f metrics-server.yaml
cd
rm -rf kubernetes_installation_docker/