VBS provides the ability to run custom scripts on parent tiers that have one or more child tiers with soft dependency configured. You can run a custom script when the application on the parent tier needs to perform a custom action when the child service group recovers from a fault. This custom action could be to issue a command for the parent tier to reconnect to the child tier.
Currently, VBS fault management provides three dependency types namely, Soft, Firm and Restart, with associated predefined fault policy actions. The Restart dependency is used when a tier can withstand lower tier failures. The upper tier continues to operate even when the lower tier fails. When the lower tier subsequently recovers, the upper tier is restarted so that it can reconnect to the lower tier.
For some applications, performing a restart in response to a lower tier recovery may be expensive and unnecessary. You can instead run a script or execute a command that resolves the problem. Such applications do not need predefined fault policy. They require the ability to detect lower tier recovery event and execute a custom script on the upper tier. The Custom Script Execution feature provides this ability.