The ability to provide detection and alarming for problems within an application is critical to building the best total fault resilient solution. Since every specific application varies on the mechanism and format of failures, no one set of generic mechanisms can be supplied. In general, however, many application configurations can rely on the Core system error detection provided within LifeKeeper Single Server Protection. This topic demonstrates the power of LifeKeeper Single Server Protection’s core facilities.
Below is a recovery scenario to demonstrate how LifeKeeper Single Server Protection provides fault detection and recovery when an application fails.
- LifeKeeper Single Server Protection will first attempt recovery by trying to restart the application.
- If the recovery succeeds, the application should continue to run normally.
- If the recovery attempt fails:
a. If the LifeKeeper Single Server Protection recovery attempt fails, and LifeKeeper Single Server Protection is installed in a VMware guest OS with HA enabled (HA_DISABLE=0 in /etc/default/LifeKeeper), then LifeKeeper Single Server Protection will trigger VMware HA by withholding the heartbeat that LifeKeeper Single Server Protection sends down to the Application Monitoring Interface. VMware HA will then respond by restarting the server.
b. If the LifeKeeper Single Server Protection recovery attempt fails, and LifeKeeper Single Server Protection is not installed in a VMware guest OS or is installed in a VMware guest OS but has HA disabled (HA_DISABLE=1 in /etc/default/LifeKeeper), then a system reboot will be forced.
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