High Availability of cron Jobs Using RCRON On Centos 6/ RHEL 6May 01, 2013, 13:00 (0 Talkback[s])
(Other stories by Nextstep4it)
High Availability using RCRON ( One Node will be stamped as Active and Second Node will be stamped as Passive ) , Same cron configuration will be on both , only difference would be active/passive state in a file.
For automatic Switching of active/passive state , we will be using KEEPALIVED Daemon , which utilizes the keepalive signal for communication between 2 nodes. After a signal is sent, if no reply is received the link is assumed to be down.
In this scenario , One node is marked as KEEPALIVED master and second as KEEPALIVED backup. Master node will keep the rcron state active , and backup node will keep the rcron state as passive. As soon as the Master Node comes down , it will send a 0 priority signal to the Backup Node , which will switch over and behave as a MASTER NODE and consecutively mark rcron as active as soon as the master node comes up again , the Backup Node will switch over to backup mode .