Kubernetes Setup

 1. Master and Worker details

Node	IP
Management	10.9.0.5
master-1	10.10.0.11
worker-1	10.10.0.12
worker-2	10.10.0.13
worker-3	10.10.0.14
worker-4	10.10.0.15
worker-5	10.10.0.16
pods	172.10.11.0/24

 

2. Some commands run on all nodes.

# yum update -y

Disable selinux  and firewalld

# systemctl stop firewalld

# systemctl disable firewalld

# /etc/sysconfig/selinux

SELINUX=disable

 

3. Update hostname and  /etc/hosts file on all nodes.

# vim /etc/hostname

master-1

# vim /etc/hosts

10.10.0.11      master-1

10.10.0.12      worker-1

10.10.0.13      worker-2

10.10.0.14      worker-3

10.10.0.15      worker-4

10.10.0.16      worker-5

10.10.0.17      common

 

4. Manually loading the modules on a Linux system.

overlay — The overlay module provides overlay filesystem support, which Kubernetes uses for its pod network abstraction.

br_netfilter — This module enables bridge netfilter support in the Linux kernel, which is required for Kubernetes networking and policy.

# sudo modprobe overlay

# sudo modprobe br_netfilter

 

5. kernel modules should be automatically loaded at boot time.

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

 

6. sysctl parameters for Kubernetes networking.

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

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

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

net/bridge/bridge-nf-call-arptables = 1

net.ipv4.ip_forward = 1

EOF

Reloading the sysctl settings.

# sudo sysctl --system

 

7. Disable the swap memory.

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

# swapoff -a

# free -m

8. Download the containerd package.

# yum install -y yum-utils

9. Add repo for containerd.

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

10. Add a repo for Kubernetes.

# cat <<EOF | sudo tee /etc/yum.repos.d/kubernetes.repo

[kubernetes]

name=Kubernetes

baseurl=https://pkgs.k8s.io/core:/stable:/v1.29/rpm/

enabled=1

gpgcheck=1

gpgkey=https://pkgs.k8s.io/core:/stable:/v1.29/rpm/repodata/repomd.xml.key

EOF

 

11. Install containerd on all nodes.

# yum install containerd -y

 

12. location where the configuration file for containerd is stored.

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

Note:- SystemdCgroup has to be set to “true”

SystemdCgroup = true

 

# systemctl status containerd

# systemctl start containerd

# systemctl enable containerd

 

13. Install kubelet and  kubeadm package on the worker node.

# yum install kubelet kubeadm -y

# systemctl enable kubelet

 

14. Install kubelet , kubeadm, kubectl package on the master node.

# yum install kubelet kubeadm kubectl -y

# systemctl enable kubelet

 

15. initializes a Kubernetes control-plane node with the specified Pod network CIDR.

# kubeadm init --pod-network-cidr=172.10.11.0/24

Note:-  If needed for cluster remove below command.

# kubeadmin reset

 

16. Run the below command on the master node.

#   mkdir -p $HOME/.kube

#  sudo cp -i /etc/kubernetes/admin.conf $HOME/.kube/config

#  sudo chown $(id -u):$(id -g) $HOME/.kube/config

For install CNI

# wget  https://raw.githubusercontent.com/projectcalico/calico/v3.27.3/manifests/calico.yaml

# kubectl apply -f calico.yaml

# kubectl get po -A

# kubectl  get nodes

 

17. Run below command in worker node for Join the worker with the master node :-

# kubeadm join 192.169.0.21:6443 --token bqyifs.ll4db25n0hb5x4t1 \

        --discovery-token-ca-cert-hash sha256:bcdc577bb0f1af8dcde2804a1d3066e2951f333d99a1892a91367e7174bf5100

 

# kubectl get nodes

# kubectl get po -A