Updated: 28 September 2026 · Applies to: AlmaLinux 9 / Rocky Linux 9 (Keepalived, Nginx)
CentOS 8 is end of life; these steps are for AlmaLinux 9 / Rocky Linux 9 (Ubuntu works the same). Keepalived moves a shared virtual IP between two Nginx servers: if the active one fails, the backup takes over the IP within seconds.
Note: The virtual IP must be allowed to move between your servers. On a VPS or cloud network this needs a failover or additional IP that the provider lets you assign to both servers; ask our support team before you set it up.
1. Install on both servers
dnf install keepalived nginx # apt install keepalived nginx on Ubuntu systemctl enable --now nginx
2. Configure the first server (MASTER)
In /etc/keepalived/keepalived.conf:
vrrp_script chk_nginx {
script "/usr/bin/systemctl is-active --quiet nginx"
interval 2
fall 2
rise 2
}
vrrp_instance VI_1 {
state MASTER
interface eth0
virtual_router_id 51
priority 150
advert_int 1
unicast_src_ip 192.0.2.11
unicast_peer {
192.0.2.12
}
authentication {
auth_type PASS
auth_pass S3cret12
}
virtual_ipaddress {
192.0.2.100/24
}
track_script {
chk_nginx
}
}
3. Configure the second server (BACKUP)
Use the same file with state BACKUP, a lower priority (for example 100), and the two IPs swapped in unicast_src_ip and unicast_peer.
4. Start and test
firewall-cmd --permanent --add-rich-rule='rule protocol value="vrrp" accept' && firewall-cmd --reload systemctl enable --now keepalived ip addr show eth0 # the MASTER shows 192.0.2.100
Stop Nginx on the master (systemctl stop nginx): within a few seconds the virtual IP appears on the backup. Point your DNS at the virtual IP, and keep the website files and configuration the same on both servers.
