protected final void checkNamespaceRSGroup(MasterProcedureEnv env, NamespaceDescriptor nd)
    throws IOException {
    Supplier<String> forWhom = () -> "namespace " + nd.getName();
    RSGroupInfo rsGroupInfo = MasterProcedureUtil.checkGroupExists(
      env.getMasterServices().getRSGroupInfoManager()::getRSGroup,
      MasterProcedureUtil.getNamespaceGroup(nd), forWhom);
    MasterProcedureUtil.checkGroupNotEmpty(rsGroupInfo, forWhom);
  }
Create the namespace directory
@param env          MasterProcedureEnv
@param nsDescriptor NamespaceDescriptor
hbase-server/src/main/java/org/apache/hadoop/hbase/master/procedure/AbstractStateMachineNamespaceProcedure.java