Kubernetes Cluster Installation Lab

Objective

Deploy a Kubernetes cluster using kubeadm, containerd, and Calico.

Environment

• Ubuntu
• Kubernetes
• Containerd
• Calico

Architecture

            +----------------+
            |  Control Plane |
            | kube-apiserver |
            | etcd           |
            | scheduler      |
            +--------+-------+
                     |
       ----------------------------
       |                          |
+------+-------+          +------+-------+
| Worker Node1 |          | Worker Node2 |
| kubelet      |          | kubelet      |
| containerd   |          | containerd   |
+------+-------+          +------+-------+
       |                          |
       +------------+-------------+
                    |
             +------+------+
             |   Calico    |
             |   Network   |
             +-------------+

Installation Steps

Setup

1. 4 VMs Ubuntu 22.04 — 1 control plane, 3 worker nodes.
2. Static IPs assigned to each VM.
3. /etc/hosts updated with hostname → IP mappings for all nodes.
4. Swap disabled on all nodes.

SSH into control plane:

ssh priyanka@my-ubuntu-1

---

Number 0 to Number 4 need to be applied on control plane and workers

---

0. Disable Swap

sudo swapoff -a
sudo vi /etc/fstab

Remove any swap entries.

---

1. Install Required Packages

Load kernel modules:

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

sudo modprobe overlay
sudo modprobe br_netfilter

System settings:

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
sudo sysctl --system

---

2. Install containerd

sudo apt-get install -y containerd
sudo mkdir -p /etc/containerd
sudo containerd config default | sudo tee /etc/containerd/config.toml

Edit containerd config to use systemd cgroups:

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

Verify:

grep 'SystemdCgroup = true' /etc/containerd/config.toml

Restart:

sudo systemctl restart containerd
sudo systemctl enable containerd

---

3. Install Kubernetes Components

Add repository:

sudo apt update && sudo apt-get install -y apt-transport-https ca-certificates curl gpg conntrack
sudo curl -fsSL https://pkgs.k8s.io/core:/stable:/v1.31/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:/v1.31/deb/ /' | sudo tee /etc/apt/sources.list.d/kubernetes.list

Update and check versions:

sudo apt-get update
apt-cache policy kubelet | head -n 20

Install Kubernetes:

VERSION=1.31.14-1.1
sudo apt-get install -y kubelet=$VERSION kubeadm=$VERSION kubectl=$VERSION
sudo apt-mark hold kubelet kubeadm kubectl containerd
sudo systemctl enable --now kubelet

---

4. Check Services

sudo systemctl status kubelet.service
sudo systemctl status containerd.service

kubelet will show inactive (dead) until cluster is initialized with kubeadm init or joined with kubeadm join.

---

5. Creating the Kubernetes Cluster

Log into the control plane:

ssh priyanka@my-ubuntu-1

Download Calico manifest:

wget https://raw.githubusercontent.com/projectcalico/calico/master/manifests/calico.yaml

Edit Pod CIDR if needed:

vi calico.yaml

Initialize the cluster:

sudo kubeadm init --kubernetes-version v1.31.14

Set up 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. Deploy Pod Network (Calico)

Apply Calico:

kubectl apply -f calico.yaml

Watch pods:

kubectl get pods --all-namespaces --watch

Check when all system pods are Running:

kubectl get pods --all-namespaces

Check nodes:

kubectl get nodes

---

7. Join Worker Nodes to the Cluster

Log out of the worker node and return to the control plane:

exit

Generate the cluster join command:

kubeadm token create --print-join-command

Copy the output — you'll need it for each worker node.

SSH into the first worker node:

ssh priyanka@my-ubuntu-2

Run the join command (example — your token will differ):

sudo kubeadm join <CONTROL_PLANE_IP>:6443 \
  --token <TOKEN> \
  --discovery-token-ca-cert-hash sha256:<HASH>

Return to control plane:

exit

Validation

Check node status (will be NotReady until network pod is deployed):

kubectl get nodes

Watch pods across all namespaces:

kubectl get pods --all-namespaces

Verify worker node becomes Ready:

kubectl get nodes

Troubleshooting

Issue 1: Worker Node Not Joining

Cause: Firewall ports were blocked.

Resolution: Required Kubernetes ports were opened and the join command was executed again.

Issue 2: Calico Pods Not Starting

Cause: Network configuration mismatch.

Resolution: Re-applied Calico manifest and verified pod status.

Lessons Learned

• Understanding of Kubernetes cluster architecture.
• Experience with kubeadm-based installation.
• Familiarity with containerd runtime configuration.
• Improved troubleshooting skills for node and networking issues.
• Better understanding of Kubernetes networking using Calico.

Project Outcome

Successfully deployed a Kubernetes cluster using kubeadm and containerd with Calico networking. Verified node readiness, system pod health, and cluster networking functionality.