code: @Override
      public void start() throws AtlasException {
          if (!HAConfiguration.isHAEnabled(configuration)) {
              LOG.info("HA is not enabled, no need to start leader election service");
              return;
          }
          cacheActiveStateChangeHandlers();
          serverId = AtlasServerIdSelector.selectServerId(configuration);
          joinElection();
      }
docs: Join leader election on starting up.
  
  If Atlas High Availability configuration is disabled, this operation is a no-op.
  @throws AtlasException