k8s Installation Steps

create best script without failure nmcli connection modify ens160 ipv4.addresses 192.168.1.15/24

nmcli connection modify ens160 ipv4.gateway 192.168.1.1

nmcli connection modify ens160 ipv4.dns "192.168.1.1"

nmcli connection modify ens160 ipv4.method manual

nmcli connection down ens160

nmcli connection up ens160

nmcli device show ens160

grep -q "192.168.1.18" /etc/hosts || echo "192.168.1.18 k8s-master" | sudo tee -a /etc/hosts

grep -q "192.168.1.15" /etc/hosts || echo "192.168.1.15 k8s-node1" | sudo tee -a /etc/hosts

grep -q "192.168.1.19" /etc/hosts || echo "192.168.1.19 k8s-node2" | sudo tee -a /etc/hosts

Each line checks if the entry exists, and only adds it if not found.

Uses sudo tee -a /etc/hosts to append with root permissions.

update the system

df -y update

systemctl stop firewalld

systemctl disable firewalld

swapoff -a

sed -i '/swap/d' /etc/fstab

setenforce 0

sed -i 's/^SELINUX=enforcing/SELINUX=disabled/' /etc/selinux/config

Enable Kernel Modules

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

overlay

br_netfilter

EOF

sudo modprobe overlay

sudo modprobe br_netfilter

Set Required sysctl Parameters

cat <<EOF | sudo tee /etc/sysctl.d/k8s.conf

net.bridge.bridge-nf-call-ip6tables = 1

net.bridge.bridge-nf-call-iptables = 1

net.ipv4.ip_forward = 1

EOF

sudo sysctl --system

Verify

lsmod | grep overlay

lsmod | grep br_netfilter

Step-by-Step: Install containerd on RHEL 9

sudo dnf install -y yum-utils device-mapper-persistent-data lvm2

Add Docker's official repository (provides containerd)

sudo yum-config-manager --add-repo https://download.docker.com/linux/centos/docker-ce.repo

Install containerd.io

dnf install -y containerd.io

Generate the default config and modify it (optional but recommended)

sudo mkdir -p /etc/containerd

containerd config default | sudo tee /etc/containerd/config.toml > /dev/null

Set containerd to use systemd cgroup driver (required for Kubernetes)

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

Enable and start containerd

sudo systemctl daemon-reexec

sudo systemctl enable --now containerd

Verify

containerd --version

sudo systemctl status containerd

Create a kubernetes repo

#vi /etc/yum.repos.d/kubernetes.repo

[kubernetes]

name=Kubernetes

baseurl=https://pkgs.k8s.io/core:/stable:/v1.31/rpm/

enabled=1

gpgcheck=1

gpgkey=https://pkgs.k8s.io/core:/stable:/v1.31/rpm/repodata/repomd.xml.key

exclude=kubelet kubeadm kubectl

#dnf update -y

Now installa kubernetes packages

dnf install -y kubelet kubeadm kubectl --disableexcludes=Kubernetes

Now start the service

sudo systemctl enable --now kubelet