Hi
This is not a common activity to perform with a cluster (VCS). You should not need to restart VCS, it is very uncommon to have to restart the cluster. The service groups however, which relate to the application, might need to be restarted but that is really just an indication that there is something wrong with the application. You need to remember that VCS doesn't do anything except start, monitor and stop the application. If there is nothing wrong with the app, VCS wont' ever need to take any action.
The fact that some resource don't come online, of fault, would need to be investigated. A resource is just one component of the application e.g. a file system, an IP address, or a process. The fault could be due to many reasons.
Which resources are failing?
You can post the engine_a.log and the log for the specific agent for review.