## What changes were proposed in this pull request? Fixed a _NullPointerException_ during blueprint install with host group level configs. Also prepared the code in _AmbariContext.createConfigGroupsAndRegisterHost_ to support multiple service instances.
## How was this patch tested? - tested blueprint installation manually - wrote new unit test and fixed/enhanced existing tests [ Full content available at: https://github.com/apache/ambari/pull/2355 ] This message was relayed via gitbox.apache.org for [email protected]
