keepalived-provision.sh

#!/bin/bash

apt-get -y update
apt-get -y install keepalived

sysctl -w net.ipv4.ip_nonlocal_bind=1

sysctl -p

cat > /etc/keepalived/keepalived.conf <<EOL
vrrp_script chk_httpd {
	script "systemctl status keepalived"
	interval 2
}

vrrp_instance LB_VIP {
	interface eth1
	state MASTER
	priority 100 / 50
	virtual_router_id 33
	authentication {
        auth_type PASS
        auth_pass secret
    }
    virtual_ipaddress {
        192.168.56.200
    }

    track_script {
        chk_httpd
    }

    virtual_server 192.168.56.200 80 {
    	lb_algo rr                                                              
    	lb_kind DR                                                               
   		protocol TCP

	    real_server 192.168.56.101 80 {
	        weight 1
	        TCP_CHECK {
	            connect_port 80
	            connect_timeout 3
	            nb_get_retry 3
	            delay_before_retry 4
	        }
    	}

    	real_server 192.168.56.102 80 {
	        weight 1
	        TCP_CHECK {
	            connect_port 80
	            connect_timeout 3
	            nb_get_retry 3
	            delay_before_retry 4
	        }
    	}

    	real_server 192.168.56.103 80 {
	        weight 1
	        TCP_CHECK {
	            connect_port 80
	            connect_timeout 3
	            nb_get_retry 3
	            delay_before_retry 4
	        }
    	}
    }
}
EOL

systemctl enable --now keepalived

nginx-provision.sh

#!/bin/bash

apt-get -y update
apt-get -y install nginx

sysctl -w net.ipv4.conf.all.arp_ignore=1
sysctl -w net.ipv4.conf.all.arp_announce=2
sysctl -p

ip addr add 192.168.56.200/24 dev eth1

service nginx start

Vagrantfile

# -*- mode: ruby -*-
# vi: set ft=ruby :

Vagrant.configure("2") do |config|

  config.vm.box = "bento/ubuntu-20.04"

  (1..3).each do |i|
    config.vm.define "nginx#{i}" do |node|
      node.vm.hostname = "nginx#{i}"
      node.vm.provision "shell", path: "nginx-provision.sh"
      node.vm.network :private_network, ip: "192.168.56.10#{i}"
    end
  end

  (1..2).each do |i|
    config.vm.define "keepalived#{i}" do |node|
      node.vm.hostname = "keepalived#{i}"
      node.vm.provision "shell", path: "keepalived-provision.sh"
      node.vm.network :private_network, ip: "192.168.56.20#{i}"
    end
  end 

  config.vm.define "client" do |node|
    node.vm.hostname = "client"
    node.vm.network :private_network, ip: "192.168.56.2"
  end
end