Kubernetes Worker Nodes

# ADD WORKER NODE CENTOS 7

# Step 1: Prepare Hostname, Firewall, and SELinux
# hostnamectl set-hostname master-node
sudo vi /etc/hosts
192.168.0.47 master-node
192.168.0.48 node-1 worker-node-1
192.168.0.49 node-2 worker-node-2

# disable Selinux  and update your firewall rules
sudo setenforce 0
sudo sed -i --follow-symlinks 's/SELINUX=enforcing/SELINUX=disabled/g' /etc/sysconfig/selinux
sudo firewall-cmd --permanent --add-port=6783/tcp
sudo firewall-cmd --permanent --add-port=10250/tcp
sudo firewall-cmd --permanent --add-port=10255/tcp
sudo firewall-cmd --permanent --add-port=30000-32767/tcp
sudo firewall-cmd  --reload
echo '1' > /proc/sys/net/bridge/bridge-nf-call-iptables

# jika error /proc/sys/net/bridge/bridge-nf-call-iptables: No such file or directory
sudo modprobe br_netfilter

# Step 2: Setup Docker-CE and Kubernetes Repo
# setelah install docker, ubah group ke systemd
docker info | grep -i cgroup
sudo vi /etc/docker/daemon.json

{
  "exec-opts": ["native.cgroupdriver=systemd"],
  "log-driver": "json-file",
  "log-opts": {
    "max-size": "100m"
  },
  "storage-driver": "overlay2",
  "storage-opts": [
    "overlay2.override_kernel_check=true"
  ]
}

# Restart Docker
sudo systemctl daemon-reload
sudo systemctl restart docker

# install kubernetes
sudo vi /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

# Step 3: Install Kubeadm
sudo yum install kubeadm

# Step 4: Join the Worker Node to the Kubernetes Cluster
# disable swap in order to run “kubeadm init“ command
sudo swapoff -a

sudo kubeadm join 192.168.0.47:6443 --token fyllch.1b6jl7p6azn16rfr \
    --discovery-token-ca-cert-hash sha256:68f2b4540eaf8794b5296f40289bf4325cec0045b885b863ae55f19ddb4b4ca2

# jika join error dir not empty, tambahkan parameter
--ignore-preflight-errors=All

# go back to your master-node and verify if worker have joined the cluster
kubectl get nodes