Handling nginx Failover With KeepAlived

Keepalived is a high-availability service that can be used to ensure that a particular service, such as an Nginx web server, is always available to handle incoming requests. It does this by monitoring the status of the service and automatically failing over to a backup server if the primary server becomes unavailable.

Here are the steps for setting up Keepalived with Nginx for failover:

1. Install Keepalived on both the primary and backup servers.
2. Configure Keepalived on the primary server by editing the Keepalived configuration file, typically located at "/etc/keepalived/keepalived.conf". In the configuration file, define the primary server as the "master" and the backup server as the "backup".
3. Configure Nginx on the primary server to listen on a virtual IP address that will be managed by Keepalived. In the Nginx configuration file, specify the virtual IP address as the "listen" address.
4. Configure Nginx on the backup server to listen on the same virtual IP address as the primary server. However, do not start the Nginx service on the backup server until it is promoted to the primary server by Keepalived.
5. Start the Keepalived service on both servers.

With this setup, Keepalived will monitor the status of the Nginx service on the primary server. If the Nginx service becomes unavailable, Keepalived will fail over to the backup server by promoting it to the primary server and starting the Nginx service on it. This will ensure that the Nginx service is always available to handle incoming requests.

Note: Keepalived is just one of several tools available for handling failover with Nginx. Other options include using a load balancer or setting up Nginx as a reverse proxy with multiple backend servers.