Now that you know all the software components in play, it's time to go deep into a web server HA configuration. This proposed design foresees Apache, bonded to a virtual IP address, on top of two nodes. In this design, the HTTPD or, better, Apache is on top of an active/passive cluster that is managed by Corosync/Pacemaker.

It is quite an easy task to provide a highly available configuration for the Zabbix GUI because the web application is well defined and does not produce or generate data or any kind of file on the web server. This allows you to have two nodes deployed on two different servers—if possible, on two distant locations—implementing a highly available fault-tolerant disaster-recovery setup. In this configuration, since the web content will be static, in the sense that it will not change (apart from the case of system upgrade), you don't need a filesystem replication between the two nodes. The only other component that is needed is...