Bài này chúng ta sẽ cần cài 2 máy chủ ubuntu: 1 với vai trò Master và 1 với vai trò Worker

Yêu cầu:

• Two Ubuntu 22.04+ servers (one master, one worker)

• Each node: 4+ CPUs, 4GB+ RAM, 50GB+ disk

• Static IPs and hostnames set

• Internet access on both nodes

1. Set Hostnames and Update Hosts File

On Master Node:

sudo hostnamectl set-hostname "elearning-k8s-master"

On Worker Node:

sudo hostnamectl set-hostname "elearning-k8s-worker1"

Hoặc bạn có thể kiểm tra lại host name bằng lệnh sau:

root@elearning-k8s-master:~# hostnamectl
 Static hostname: elearning-k8s-master
       Icon name: computer-vm
         Chassis: vm
      Machine ID: a6047e6b11ae4a39ab3ee07f837b2493
         Boot ID: e02d11c5972245b5a895c0c0ab9b6dcc
  Virtualization: vmware
Operating System: Ubuntu 22.04.2 LTS              
          Kernel: Linux 5.15.0-141-generic
    Architecture: x86-64

On Both Nodes:
Edit /etc/hosts to include both nodes’ IPs and hostnames:

192.168.101.150 elearning-k8s-master
192.168.101.151 elearning-k8s-worker1

Replace IPs with your actual addresses

2. Disable Swap and Configure Kernel Parameters

On Both Nodes:

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

Load kernel modules:

sudo tee /etc/modules-load.d/containerd.conf <<EOF
overlay
br_netfilter
EOF

sudo modprobe overlay
sudo modprobe br_netfilter 

Set sysctl params:

sudo tee /etc/sysctl.d/kubernetes.conf <<EOF
net.bridge.bridge-nf-call-ip6tables = 1
net.bridge.bridge-nf-call-iptables = 1
net.ipv4.ip_forward = 1
EOF

sudo sysctl --system

3. Install Container Runtime (containerd)

On Both Nodes:

sudo apt update
sudo apt install -y curl gnupg2 software-properties-common apt-transport-https ca-certificates
curl -fsSL https://download.docker.com/linux/ubuntu/gpg | sudo gpg --dearmor -o /etc/apt/trusted.gpg.d/docker.gpg
sudo add-apt-repository "deb [arch=amd64] https://download.docker.com/linux/ubuntu $(lsb_release -cs) stable"
sudo apt update
sudo apt install -y containerd.io

Configure containerd:

sudo mkdir -p /etc/containerd
containerd config default | sudo tee /etc/containerd/config.toml >/dev/null 2>&1
sudo sed -i 's/SystemdCgroup = false/SystemdCgroup = true/g' /etc/containerd/config.toml
sudo systemctl restart containerd
sudo systemctl enable containerd

4. Add Kubernetes Repository and Install Tools

On Both Nodes:

sudo mkdir -p /etc/apt/keyrings
curl -fsSL https://pkgs.k8s.io/core:/stable:/v1.34/deb/Release.key | sudo gpg --dearmor -o /etc/apt/keyrings/kubernetes-apt-keyring.gpg
echo 'deb [signed-by=/etc/apt/keyrings/kubernetes-apt-keyring.gpg] https://pkgs.k8s.io/core:/stable:/v1.34/deb/ /' | sudo tee /etc/apt/sources.list.d/kubernetes.list
sudo apt update
sudo apt install -y kubelet kubeadm kubectl
sudo apt-mark hold kubelet kubeadm kubectl

5. Initialize Kubernetes Cluster (Master Node Only)

On Master Node:

sudo kubeadm init --control-plane-endpoint=elearning-k8s-master --pod-network-cidr=192.168.0.0/16

The --pod-network-cidr is required for most network plugins (e.g., Calico, Flannel)

Khi cài đặt cho master thành công nó sẽ báo như sau:

After initialization, follow the on-screen instructions to set up your kubeconfig:

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

6. Install a Pod Network Add-on (Master Node Only)

Example: Calico

kubectl apply -f https://raw.githubusercontent.com/projectcalico/calico/v3.26.0/manifests/calico.yaml

kubectl get nodes

sudo kubeadm join k8smaster:6443 --token <token> --discovery-token-ca-cert-hash sha256:<hash>

kubectl get nodes

kubectl create deployment nginx-app --image=nginx --replicas=2
kubectl get deployment nginx-app
kubectl expose deployment nginx-app --type=NodePort --port=80
kubectl get svc nginx-app