Kubernetes Installation on Ubuntu 22.04

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

cri-o

Kubernetes

Set up the cri-o and Kubernetes repositories:

Download and install the necessary tools for Cri-o

sudo apt update
sudo apt install -y apt-transport-https ca-certificates curl gnupg2 software-properties-common

# Export the OS and CRI_O version values
export OS_VERSION=xUbuntu_22.04
export CRIO_VERSION=1.28

Download the GPG key for cri-o

sudo curl -fsSL https://download.opensuse.org/repositories/devel:/kubic:/libcontainers:/stable/$OS_VERSION/Release.key | sudo gpg --dearmor -o /usr/share/keyrings/libcontainers-archive-keyring.gpg

sudo curl -fsSL https://download.opensuse.org/repositories/devel:/kubic:/libcontainers:/stable:/cri-o:/$CRIO_VERSION/$OS_VERSION/Release.key | sudo gpg --dearmor -o /usr/share/keyrings/libcontainers-crio-archive-keyring.gpg

Add the cri-o repository

# we can get the latest release details from https://cri-o.io/

sudo echo "deb [signed-by=/usr/share/keyrings/libcontainers-archive-keyring.gpg] https://download.opensuse.org/repositories/devel:/kubic:/libcontainers:/stable/$OS_VERSION/ /" | sudo tee /etc/apt/sources.list.d/devel:kubic:libcontainers:stable.list

sudo echo "deb [signed-by=/usr/share/keyrings/libcontainers-crio-archive-keyring.gpg] https://download.opensuse.org/repositories/devel:/kubic:/libcontainers:/stable:/cri-o:/$CRIO_VERSION/$OS_VERSION/ /" | sudo tee /etc/apt/sources.list.d/devel:kubic:libcontainers:stable:cri-o:$CRIO_VERSION.list

Add the GPG key for kubernetes

curl -fsSL https://pkgs.k8s.io/core:/stable:/v1.31/deb/Release.key | sudo gpg --dearmor -o /etc/apt/keyrings/kubernetes-apt-keyring.gpg

Add the kubernetes repository

Check for the latest release in https://packages.cloud.google.com/apt/dists

echo "deb [signed-by=/etc/apt/keyrings/kubernetes-apt-keyring.gpg] https://pkgs.k8s.io/core:/stable:/v1.31/deb/ /" | sudo tee /etc/apt/sources.list.d/kubernetes.list

Update the repository

# Update the repositiries
sudo apt-get update

Install cri-o and Kubernetes packages.

Note that if you want to use a newer version of Kubernetes, change the version installed for kubelet, kubeadm, and kubectl and be sure that all three use the same version. These version should support the cri-o version.

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

# Start the cri-o service
sudo systemctl daemon-reload
sudo systemctl enable crio
sudo systemctl start crio

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

sudo apt-mark hold cri-o 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

Disable SWAP

Disable swap on controlplane and dataplane nodes

sudo swappff -a

sudo vim /etc/fstab
# comment the line which starts with **swap.img**.

On the Kube master server

Initialize the cluster by passing the cidr value.

Use Calico

# Calico network
# Make sure to copy and backup the join command
sudo kubeadm init --pod-network-cidr=192.168.0.0/16 --cri-socket unix:///var/run/crio/crio.sock

# Copy your join command and keep it safe.
# Below is a sample
kubeadm join 10.128.0.2:6443 --token swi0ci.jq9l75eg8lvpxz6g --discovery-token-ca-cert-hash sha256:2c3cdfa898334b0dfc0f73bbccb998d03f61252ee50f0405c85ba735ff90b4d1

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/v3.28.2/manifests/tigera-operator.yaml

curl https://raw.githubusercontent.com/projectcalico/calico/v3.28.2/manifests/custom-resources.yaml -O


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

TIP

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

kubeadm token create --print-join-command

To install the metrics server

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