Initialize Addional Master nodes

There is a slight discrepancy between initializing the first master node and additional master nodes

Dependency

• Completed the guidance of Kubeadm Setup

• Completed the guidance of Initialize First Master Node

The following procedures required root permission. Please switch to root account or execute command with sudo

Enable kubectl auto-completion for bash

Enable kubectl autocompletion https://kubernetes.io/docs/tasks/tools/install-kubectl-linux/#optional-kubectl-configurations-and-plugins

Ensure that the kubectl completion script gets sourced in all your shell sessions

kubectl completion bash | sudo tee /etc/bash_completion.d/kubectl > /dev/null
sudo chmod a+r /etc/bash_completion.d/kubectl

Extend shell completion to work with alias-k

echo 'alias k=kubectl' >> /etc/bash_completion.d/kubectl
echo 'complete -o default -F __start_kubectl k' >>  /etc/bash_completion.d/kubectl

Clone the kube-vip configuration file

Create kube-vip manifest yaml

sudo mkdir -p /etc/kubernetes/manifests/

Clone the kube-vip.yaml from first master node

scp root@master1:/etc/kubernetes/manifests/kube-vip.yaml /etc/kubernetes/manifests/kube-vip.yaml

Join Kubernetes cluster as a control plane

Append master nodes and vip host into hosts file

cat <<EOF >> /etc/hosts
#Kube-vip
192.168.x.xx   kube-vip-lb
#Master nodes
192.168.x.xx   master1
192.168.x.xx   master2
192.168.x.xx   master3
#Worker nodes
192.168.x.xx   worker1
192.168.x.xx   worker1
EOF

Run the join command that shown on first Master node

The command was prompted after initializing the first master node

kubeadm join 192.168.xx.xx:6443 --token 36qsk5.lbcqztfj1y4brajo \
    --discovery-token-ca-cert-hash sha256:37ae5bd9b4f38ae8519883ba9c443da8e6cba1d23898f652347e0f614fb1418c \
    --control-plane --certificate-key e1c25100ff2ca029bc8ca2151c8c5456d2776e2faae63726bc116638e323daec

Source out KUBECONFIG for root user

echo "export KUBECONFIG=/etc/kubernetes/admin.conf" >> /root/.bashrc
source /root/.bashrc

Create regular user

Create user for k8suser

useradd -m k8suser

Set password for k8suser

passwd k8suser

Grant sudo privileges

visudo

Insert above line into the file

k8suser    ALL=(ALL)       ALL

Add user k8suser to the docker group

usermod -aG docker k8suser

Check which groups a user belongs to

groups k8suser

Switch to user k8suser to manage Kubernetes cluster

su k8suser
mkdir -p $HOME/.kube
sudo cp -i /etc/kubernetes/admin.conf $HOME/.kube/config
sudo chown $(id -u):$(id -g) $HOME/.kube/config