public String isRunningCommand(ServiceType service) {
      return findPidCommand(service);
    }
Provides command strings for services to be executed by Shell. CommandProviders are pluggable,
and different deployments(windows, bigtop, etc) can be managed by plugging-in custom
CommandProvider's or ClusterManager's.
hbase-it/src/test/java/org/apache/hadoop/hbase/HBaseClusterManager.java