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Kubernetes Cluster Installation Guide#

Steps

Sanity Setup and Pre-requisites#

Perform Sanity Checks on All Hosts

# 1. Disable SELinux on all hosts.
# 2. Docker user should have root access.
# 3. Add host entries.
# 4. Disable swap on all hosts.
# 5. Enable passwordless SSH from docker user and root.

Master Node Setup#

SSH into the Master Node

ssh user@master-node

Disable Swap

swapoff -a
sudo sed -i '/ swap / s/^\(.*\)$/#\1/g' /etc/fstab

Configure Networking for Kubernetes

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

sudo modprobe overlay
sudo modprobe br_netfilter

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
lsmod | grep br_netfilter
lsmod | grep overlay
sysctl net.bridge.bridge-nf-call-iptables net.bridge.bridge-nf-call-ip6tables net.ipv4.ip_forward
sysctl -p

Install Container Runtime (containerd)

yum install -y containerd-*.rpm

curl -LO https://github.com/containerd/containerd/releases/download/v1.7.14/containerd-1.7.14-linux-amd64.tar.gz
sudo tar Cxzvf /usr/local containerd-1.7.14-linux-amd64.tar.gz
curl -LO https://raw.githubusercontent.com/containerd/containerd/main/containerd.service
sudo mkdir -p /usr/local/lib/systemd/system/
sudo mv containerd.service /usr/local/lib/systemd/system/
sudo mkdir -p /etc/containerd
containerd config default | sudo tee /etc/containerd/config.toml
sudo sed -i 's/SystemdCgroup \= false/SystemdCgroup \= true/g' /etc/containerd/config.toml

Enable and Start containerd

sudo systemctl daemon-reload
sudo systemctl enable --now containerd
systemctl status containerd

Install Runc

yum install -y runc

curl -LO https://github.com/opencontainers/runc/releases/download/v1.1.12/runc.amd64
sudo install -m 755 runc.amd64 /usr/local/sbin/runc

Install CNI Plugin

curl -LO https://github.com/containernetworking/plugins/releases/download/v1.5.0/cni-plugins-linux-amd64-v1.5.0.tgz
sudo mkdir -p /opt/cni/bin
sudo tar Cxzvf /opt/cni/bin cni-plugins-linux-amd64-v1.5.0.tgz

Install Kubernetes Components

# Download rpm from official kubernetes documentation
yum install -y kube*.rpm
kubeadm version
kubelet --version
kubectl version --client

Configure crictl for Containerd

sudo crictl config runtime-endpoint unix:///var/run/containerd/containerd.sock

Initialize Kubernetes Control Plane

# Load necessary Kubernetes images before initializing
kubeadm config images list
# Example images:
# registry.k8s.io/kube-apiserver:v1.30.1
# registry.k8s.io/kube-controller-manager:v1.30.1
# registry.k8s.io/kube-scheduler:v1.30.1
# registry.k8s.io/kube-proxy:v1.30.1
# registry.k8s.io/coredns/coredns:v1.11.1
# registry.k8s.io/pause:3.9
# registry.k8s.io/etcd:3.5.12-0

kubeadm init --kubernetes-version=v1.30.1 \
  --control-plane-endpoint "hostIP:6443" \
  --upload-certs \
  --pod-network-cidr=10.244.0.0/16 \
  --apiserver-advertise-address=hostIP

Set Up kubeconfig for kubectl

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

Install Calico for Networking

wget https://github.com/manish-chet/DataEngineering/blob/main/kubernetes/calico_edited.yaml
kubectl apply -f calico_edited.yaml

Worker Node Setup#

Repeat Master node Setup Steps and Join Cluster

# Repeat the above steps on all worker nodes, then join them to the cluster:
sudo kubeadm join hostIP:6443 --token xxxxx --discovery-token-ca-cert-hash sha256:xxx
If you need the join command again, run the following on the master node: 
kubeadm token create --print-join-command

Validation#

Validate Cluster Status

kubectl get nodes
kubectl get pods -A

References#