During testing of the integration with the component layout recommendations API, Bence Sari noticed that there are times when the StackAdvisor will suggest components that should not be added to a given cluster.
In some cases, it appears that the Zookeeper Failover-Controller component ("ZKFC") will be recommended by the StackAdvisor in cases where HDFS HA is not enabled, which is not the expected behavior.
The "Add Service" API should support a mechanism for specifying a set of components that should be ignored when recommended by the StackAdvisor. When this new configuration property is specified, the "Add Service" API should remove the given components from the component set provided by the StackAdvisor during an Add Service operation.
While this will probably not be used generally, we'll need this option in place to handle non-standard Ambari deployments (Example: Cumulus) in a generic fashion.