@Override
      public void run() {
        LOG.info("Start migrating table rs group config");
        while (!masterServices.isStopped()) {
          Collection<RSGroupInfo> groups = holder.groupName2Group.values();
          boolean hasTables = groups.stream().anyMatch(r -> !r.getTables().isEmpty());
          if (!hasTables) {
            break;
          }
          migrate(groups);
        }
        LOG.info("Done migrating table rs group info");
      }
Returns Set of online Servers named for their hostname and port (not ServerName).
hbase-server/src/main/java/org/apache/hadoop/hbase/rsgroup/RSGroupInfoManagerImpl.java