How to Set Up High Availability

Prerequisites

High availability requires multiple VPS instances. This is an advanced topic.

Before starting, make sure you have:

• At least two VPS servers
• Root or sudo access on all
• Load balancer knowledge

Option 1: DNS Failover (Simple)

Use a DNS provider with failover (e.g., Cloudflare, Route53).

Set two A records with low TTL (e.g., 60 seconds) and enable monitoring.

Option 2: Floating IP with Keepalived

Install keepalived:

sudo apt install keepalived -y

Configure on primary (master):

sudo nano /etc/keepalived/keepalived.conf

vrrp_instance VI_1 {
    state MASTER
    interface eth0
    virtual_router_id 51
    priority 100
    advert_int 1
    authentication {
        auth_type PASS
        auth_pass yourpassword
    }
    virtual_ipaddress {
        192.168.1.100/24
    }
}

On backup, set state BACKUP and priority 90.

Start keepalived on both.

Option 3: Load Balancer (HAProxy) + Two Backend VPS

Install HAProxy on a separate VPS or use two with floating IP.

sudo apt install haproxy -y

Configure /etc/haproxy/haproxy.cfg:

frontend http_front
    bind *:80
    default_backend http_back

backend http_back
    balance roundrobin
    server web1 VPS1_IP:80 check
    server web2 VPS2_IP:80 check

Option 4: Database Replication (Already covered in Article 47)

Set up master-master or master-slave replication.

Option 5: Use Hostxpeed Load Balancer (If Offered)

Contact Hostxpeed to inquire about load balancing services.