private void loadDeployedRegions() throws IOException, InterruptedException {
    // From the master, get a list of all known live region servers
    Collection<ServerName> regionServers = status.getLiveServerMetrics().keySet();
    errors.print("Number of live region servers: " + regionServers.size());
    if (details) {
      for (ServerName rsinfo : regionServers) {
        errors.print("  " + rsinfo.getServerName());
      }
    }

    // From the master, get a list of all dead region servers
    Collection<ServerName> deadRegionServers = status.getDeadServerNames();
    errors.print("Number of dead region servers: " + deadRegionServers.size());
    if (details) {
      for (ServerName name : deadRegionServers) {
        errors.print("  " + name);
      }
    }

    // Print the current master name and state
    errors.print("Master: " + status.getMasterName());

    // Print the list of all backup masters
    Collection<ServerName> backupMasters = status.getBackupMasterNames();
    errors.print("Number of backup masters: " + backupMasters.size());
    if (details) {
      for (ServerName name : backupMasters) {
        errors.print("  " + name);
      }
    }

    errors.print("Average load: " + status.getAverageLoad());
    errors.print("Number of requests: " + status.getRequestCount());
    errors.print("Number of regions: " + status.getRegionCount());

    List<RegionState> rits = status.getRegionStatesInTransition();
    errors.print("Number of regions in transition: " + rits.size());
    if (details) {
      for (RegionState state : rits) {
        errors.print("  " + state.toDescriptiveString());
      }
    }

    // Determine what's deployed
    processRegionServers(regionServers);
  }
Get deployed regions according to the region servers.
hbase-server/src/main/java/org/apache/hadoop/hbase/util/HBaseFsck.java