Kubernetes High Availability Cluster Installation

1) HAProxy Installation

HAProxy is an open-source proxy and load balancing solution used to provide high availability. Below is the installation guide for Ubuntu operating systems.

sudo apt update
sudo apt install haproxy

YML

The configuration file is edited.

sudo vi /etc/haproxy/haproxy.cfg

YML

frontend kubernetes-frontend
  bind *:6443
  mode tcp
  option tcplog
  default_backend kubernetes-backend
 
backend kubernetes-backend
  option httpchk GET /healthz
  http-check expect status 200
  mode tcp
  option ssl-hello-chk
  balance roundrobin
    server master1hostname <MASTER_1_IP>:6443 check fall 3 rise 2
    server master2hostname <MASTER_2_IP>:6443 check fall 3 rise 2
    server master3hostname <MASTER_3_IP>:6443 check fall 3 rise 2

POWERSHELL

systemctl enable haproxy && systemctl restart haproxy
systemctl status haproxy

POWERSHELL

1) Keepalived Installation

Keepalived typically provides a Virtual IP address among several control nodes (master and backup masters) and is used to ensure the continuous operation of other services.

sudo vim /etc/keepalived/check_apiserver.sh

POWERSHELL

#!/bin/sh
 
errorExit() {
  echo "*** $@" 1>&2
  exit 1
}
 
curl --silent --max-time 2 --insecure https://localhost:6443/ -o /dev/null || errorExit "Error GET https://localhost:6443/"
if ip addr | grep -q <VIRTUAL_IP>; then
  curl --silent --max-time 2 --insecure https://<VIRTUAL_IP>:6443/ -o /dev/null || errorExit "Error GET https://<VIRTUAL_IP>:6443/"
fi

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chmod +x /etc/keepalived/check_apiserver.sh

POWERSHELL

Note: Add the appropriate network interface in the 'Interface' field.

sudo vim /etc/keepalived/keepalived.conf

POWERSHELL

vrrp_script check_apiserver {
  script "/etc/keepalived/check_apiserver.sh"
  interval 3
  timeout 10
  fall 5
  rise 2
  weight -2
}
 
vrrp_instance VI_1 {
    state BACKUP
    interface eth1
    virtual_router_id 1
    priority 100
    advert_int 5
    authentication {
        auth_type PASS
        auth_pass mysecret
    }
    virtual_ipaddress {  
     <VIRTUAL_IP>    
 }
    track_script {
        check_apiserver
    }
}

POWERSHELL

systemctl enable --now keepalived

POWERSHELL

Initializing Kubernetes Cluster

You can perform the Kubernetes installation using the document Installation of Apinizer on Ubuntu OS

Important: During the init process, you should enter your own virtual IP address as the endpoint.

kubeadm init --control-plane-endpoint="<VIRTUAL_IP>:6443" --upload-certs --pod-network-cidr=10.244.0.0/16

POWERSHELL