I think currently it is not possible to know the services up and running in a cluster using Cloudera Manager CM API. This would be nice feature if the CM API can expose this details also. The same is possible using the Web UI of Cloudera Manager.
My use case : I'm developing a tool to automate the installation of a hadoop application that use CDH distribution and the cluster is managed by Cloudera Manager. I need to know the version of each and every service(Hive, imapala, solr etc.) up and running in the cluster to make sure the versions in the target environment are compatible with my application.