Kubernetes cluster installation.

########### Kubernetes Cluster Setup ######


############ for Master ##############
Step 1: Prepare Hostname, Firewall and SELinux
On your master node, set the hostname and if you don’t have a DNS server, then also update your /etc/hosts file.
# vim /etc/hosts
192.168.56.101        master.example.com master
192.168.56.102        worker01
192.168.56.103        worker02
 
# Install Kubernetes
# sudo modprobe overlay
# sudo modprobe br_netfilter
# 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
EOF
 
disable SElinux and update your firewall rules.
#sudo setenforce 0
#sudo sed -i 's/^SELINUX=.*/SELINUX=permissive/g' /etc/selinux/config
 
# cat <<EOF | sudo tee /etc/yum.repos.d/kubernetes.repo
[kubernetes]
name=Kubernetes
baseurl=https://packages.cloud.google.com/yum/repos/kubernetes-el7-x86_64
enabled=1
gpgcheck=1
repo_gpgcheck=1
gpgkey=https://packages.cloud.google.com/yum/doc/yum-key.gpg https://packages.cloud.google.com/yum/doc/rpm-package-key.gpg
EOF
 
# sudo sysctl --system
# sudo sed -i '/ swap / s/^\(.*\)$/#\1/g' /etc/fstab
# sudo swapoff -a
# yum install -y yum-utils
# yum-config-manager --add-repo https://download.docker.com/linux/centos/docker-ce.repo
# yum install -y docker-ce docker-ce-cli containerd.io docker-compose-plugin  kubelet kubectl kubeadm kubernetes-cni
# systemctl enable kubelet
# systemctl enable docker
# service firewalld stop
# systemctl disable firewalld
# rm -f /etc/containerd/config.toml
# systemctl restart containerd
# systemctl enable containerd
# echo -e "192.168.50.10 master\n192.168.50.11 worker1\n192.168.50.12 worker2" >> /etc/hosts
# kubeadm config images pull
# kubeadm init --apiserver-advertise-address=192.168.50.10 --pod-network-cidr=10.244.0.0/16
# mkdir -p $HOME/.kube
# sudo cp -i /etc/kubernetes/admin.conf $HOME/.kube/config
# sudo chown $(id -u):$(id -g) $HOME/.kube/config
# kubectl apply -f https://raw.githubusercontent.com/coreos/flannel/master/Documentation/kube-flannel.yml
# systemctl status containerd
# systemctl status kubelet
 
######################## worker01 ##############################
Step 1: Prepare Hostname, Firewall and SELinux
 
On your master node, set the hostname and if you don’t have a DNS server, then also update your /etc/hosts file.
# vim /etc/hosts
192.168.56.101        master.example.com master
192.168.56.102        worker01
192.168.56.103        worker02
 
sudo modprobe overlay
sudo modprobe br_netfilter
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
EOF
 
 
# cat <<EOF | sudo tee /etc/yum.repos.d/kubernetes.repo
[kubernetes]
name=Kubernetes
baseurl=https://packages.cloud.google.com/yum/repos/kubernetes-el7-x86_64
enabled=1
gpgcheck=1
repo_gpgcheck=1
gpgkey=https://packages.cloud.google.com/yum/doc/yum-key.gpg https://packages.cloud.google.com/yum/doc/rpm-package-key.gpg
EOF
 # sudo sysctl --system

 # sudo setenforce 0
 # sudo sed -i 's/^SELINUX=.*/SELINUX=permissive/g' /etc/selinux/config
 # sudo sed -i '/ swap / s/^\(.*\)$/#\1/g' /etc/fstab
 # sudo swapoff -a
 # yum install -y yum-utils
 # yum-config-manager --add-repo https://download.docker.com/linux/centos/docker-ce.repo
 # yum install -y docker-ce docker-ce-cli containerd.io docker-compose-plugin  kubelet kubectl kubeadm kubernetes-cni
# systemctl enable kubelet
# systemctl enable docker
# service firewalld stop
# systemctl disable firewalld
# rm -f /etc/containerd/config.toml
# systemctl restart containerd
# systemctl status kubelet
# echo -e "192.168.56.101 master\n192.168.56.102 worker01\n192.168.56.103 worker02" >> /etc/hosts

# systemctl status kubelet --> nahi chalega..
# kubeadm join 192.168.56.101:6443 --token al34ik.aocuycxej7cu9e09\

      --discovery-token-ca-cert-hash sha256:79c40e306623488a85aac952930cad89d825069d0801c0c9b9dcca9897bd5a22 --v=5
# systemctl status kubelet --> worker join ke badh chal jayega..
# systemctl status containerd
# systemctl status kubelet
on Master  node command :- 
# sudo kubectl label node <worker01> node-role.kubernetes.io/worker=worker
[root@master ~]# kubectl get nodes
NAME                 STATUS   ROLES           AGE   VERSION
master.example.com   Ready    control-plane   11h   v1.28.2
worker01             Ready    worker          10h   v1.28.2
worker02             Ready    worker          10h   v1.28.2
 
####### Reset  k8s cluster ############
kubeadm reset
#####################################