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RedHat-HA-KubernetesCluster

Set up a Highly Available Kubernetes Cluster using kubeadm

Follow this documentation to set up a highly available Kubernetes cluster using Red Hat Enterprise Linux 8.3(Ootpa)

This documentation guides you in setting up a cluster with three master nodes, three worker nodes and a load balancer node using HAProxy.

Virtual Machines Environment

Role FQDN IP OS RAM CPU
Load Balancer rhellb1 192.168.1.8 RHEL 8.3 8G 2
Master rhelmaster1 192.168.1.2 RHEL 8.3 8G 2
Master rhelmaster2 192.168.1.3 RHEL 8.3 8G 2
Master rhelmaster3 192.168.1.4 RHEL 8.3 8G 2
Worker rhelworker1 192.168.1.5 RHEL 8.3 8G 2
Worker rhelworker1 192.168.1.6 RHEL 8.3 8G 2
Worker rhelworker1 192.168.1.7 RHEL 8.3 8G 2

Pre-requisites Master

Use bootstrap scripts to set up iptables:

  • Open port 2222 on OpenSSH
  • Open port 6443 on Kube-apiserver
  • Open port 2379-2380 on etcd server client API
  • Open 10250 on Kubelet API
  • Open 10251 on Kube-scheduler
  • Open 10252 on Kube-controller-Manager

Pre-requisites Worker

  • Open port 2222 on OpenSSH
  • Open port 10250 on Kubelet API
  • Open port 30000-32767 on NodePort Services

Set up load balancer node

Install Haproxy
yum update && yum install -y haproxy
Configure haproxy

Append the below lines to /etc/haproxy/haproxy.cfg

frontend kubernetes-frontend
    bind 192.168.1.8:6443
    mode tcp
    option tcplog
    default_backend kubernetes-backend

backend kubernetes-backend
    mode tcp
    option tcp-check
    balance roundrobin
    server rhelmaster1 192.168.1.2:6443 check fall 3 rise 2
    server rhelmaster2 192.168.1.3:6443 check fall 3 rise 2
    server rhelmaster3 192.168.1.4:6443 check fall 3 rise 2
Restart haproxy service
systemctl restart haproxy

Set up cluster

Run ansible-playbook on Masternode1 with ip 192.168.1.2
git clone https://github.com/grzegorzgniadek/RedHatK8SCluster-Ansible
cd RedHat-HA-KubernetesCluster
ansible-playbook -Kk site.yaml
Verifying the cluster
kubectl cluster-info
kubectl get nodes
kubectl get cs