# K8S Installation Steps
Date: Oct 2023
OS: Ubuntu 22.04
Kubernetes: 1.26.4
Calico: 3.26.3
Node: 1 x control + 2 x workers

**1. Node preparation**
On the control plane node:
`sudo hostnamectl set-hostname k8s-control`

On the first worker node:

`sudo hostnamectl set-hostname k8s-worker1`

On the second worker node:

`sudo hostnamectl set-hostname k8s-worker2`

On all nodes, set up the hosts file to enable all the nodes to reach each other using these hostnames.

sudo vi /etc/hosts

On all nodes, add the following at the end of the file. You will need to supply the actual private IP address for each node.

<control plane node private IP> k8s-control
<worker node 1 private IP> k8s-worker1
<worker node 2 private IP> k8s-worker2

Disable and turn off SWAP

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

Stop and disable Ubuntu ufw
`sudo systemctl disable --now ufw`

Loading K8s required Kernel Modules

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

#reload kernel modules
sudo modprobe overlay
sudo modprobe br_netfilter

Setup iptables to check bridge network flow

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

# reload sysctl.d
sudo sysctl --system

**2. Containerd installation on all nodes**
* Reference: https://kubernetes.io/docs/setup/production-environment/tools/kubeadm/install-kubeadm/
* https://gist.github.com/kkbruce/c632e946c59f04ea8d7ce20f6f80b26d

sudo apt install -y curl gnupg2 software-properties-common apt-transport-https ca-certificates
sudo curl -fsSL https://download.docker.com/linux/ubuntu/gpg | sudo gpg --dearmor -o /usr/share/keyrings/docker-archive-keyring.gpg
echo "deb [arch=$(dpkg --print-architecture) signed-by=/usr/share/keyrings/docker-archive-keyring.gpg] https://download.docker.com/linux/ubuntu $(lsb_release -cs) stable" | sudo tee /etc/apt/sources.list.d/docker.list

# install containerd.io
sudo apt update
sudo apt install -y containerd.io

# generate default config
sudo containerd config default | sudo tee /etc/containerd/config.toml

# Configuring a cgroup driver !!very important!!
# https://kubernetes.io/docs/setup/production-environment/container-runtimes/#containerd-systemd
sudo sed -i 's/SystemdCgroup \= false/SystemdCgroup \= true/g' /etc/containerd/config.toml

# restart containerd
sudo systemctl restart containerd
sudo systemctl enable containerd

**3. Install kubeadm, kubelet and kubectl on all nodes**
Make disable all swap before this step
Reference: https://kubernetes.io/docs/setup/production-environment/tools/kubeadm/install-kubeadm/

curl -s https://packages.cloud.google.com/apt/doc/apt-key.gpg | sudo apt-key add -

cat << EOF | sudo tee /etc/apt/sources.list.d/kubernetes.list
deb https://apt.kubernetes.io/ kubernetes-xenial main
EOF

#Update the apt package index, install kubelet, kubeadm and kubectl, and pin their version:
# https://kubernetes.io/docs/setup/production-environment/tools/kubeadm/install-kubeadm/#installing-kubeadm-kubelet-and-kubectl

sudo apt-get update
sudo apt-get install -y kubelet=1.26.4-00 kubeadm=1.26.4-00 kubectl=1.26.4-00
sudo apt-mark hold kubelet kubeadm kubectl

**4. On the control plane node only, initialize the cluster and set up kubectl access.**
Reference: https://kubernetes.io/docs/setup/production-environment/tools/kubeadm/create-cluster-kubeadm/

sudo kubeadm init --pod-network-cidr 192.168.0.0/16 --kubernetes-version 1.26.4
mkdir -p $HOME/.kube
sudo cp -i /etc/kubernetes/admin.conf $HOME/.kube/config
sudo chown $(id -u):$(id -g) $HOME/.kube/config

Verify the cluster is working. It takes around 15 mins for the status change from NotReady to Ready state

kubectl get nodes -o wide
NAME          STATUS   ROLES           AGE   VERSION   INTERNAL-IP    EXTERNAL-IP   OS-IMAGE             KERNEL-VERSION   CONTAINER-RUNTIME
k8s-control   Ready    control-plane   15m   v1.26.4   172.31.22.65   <none>        Ubuntu 22.04.3 LTS   6.2.0-1009-aws   containerd://1.6.24

kubectl get cs
Warning: v1 ComponentStatus is deprecated in v1.19+
NAME                 STATUS    MESSAGE                         ERROR
scheduler            Healthy   ok                              
controller-manager   Healthy   ok                              
etcd-0               Healthy   {"health":"true","reason":""}   

**5. Install Calico network add-on on control node**
Reference: https://docs.tigera.io/calico/latest/getting-started/kubernetes/quickstart
Check the latest version and support matrix before installation

kubectl apply -f https://raw.githubusercontent.com/projectcalico/calico/v3.26.3/manifests/calico.yaml

**6. Join worker node to the cluster**
Get the join command. this command is also printed during kubeadm init

`kubeadm token create --print-join-command`
Copy the join command from the control plane node. Run it on each worker node as root.

`sudo kubeadm join ...`

On the control plane node, verify all nodes in your cluster are ready. Note that it may take a few moments for all of the nodes to
enter the READY state.

kubectl get nodes
NAME          STATUS   ROLES           AGE   VERSION   INTERNAL-IP     EXTERNAL-IP   OS-IMAGE             KERNEL-VERSION   CONTAINER-RUNTIME
k8s-control   Ready    control-plane   21m   v1.26.4   172.31.22.65    <none>        Ubuntu 22.04.3 LTS   6.2.0-1009-aws   containerd://1.6.24
k8s-worker1   Ready    <none>          79s   v1.26.4   172.31.21.187   <none>        Ubuntu 22.04.3 LTS   6.2.0-1009-aws   containerd://1.6.24
k8s-worker2   Ready    <none>          47s   v1.26.4   172.31.25.96    <none>        Ubuntu 22.04.3 LTS   6.2.0-1009-aws   containerd://1.6.2