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