NGINX Cookbook, 3rd Edition

Chapter 12. High-Availability Deployment Modes

12.0 Introduction

Fault-tolerant architecture separates systems into identical, independent stacks. Load balancers like NGINX are employed to distribute load, ensuring that what’s provisioned is utilized. The core concepts of high availability are load balancing over multiple active nodes or an active-passive failover. Highly available applications have no single points of failure; every component must use one of these concepts, including the load balancers themselves. For us, that means NGINX. NGINX is designed to work in either configuration: multiple active or active-passive failover. This chapter details techniques on how to run multiple NGINX servers to ensure high availability in your load-balancing tier.

12.1 NGINX Plus HA Mode

Problem

You need a highly available (HA) load-balancing solution in an on-premises deployment.

Solution

Use NGINX Plus’s HA mode with keepalived by installing the nginx-ha-keepalived package from the NGINX Plus repository on two or more systems:

$ sudo apt update
$ sudo apt install -y nginx-ha-keepalived

Use the nginx-ha-setup script to bootstrap a keepalived configuration file on each system, and follow through the prompts:

$ sudo nginx-ha-setup

Review the configuration file generated by the nginx-ha-setup command:

$ sudo cat /etc/keepalived/keepalived.conf

global_defs {
  vrrp_version 3
}


vrrp_script chk_manual_failover {
  script "/usr/lib/keepalived/nginx-ha-manual-failover"
  interval