code: def atlas_init(blockstack_opts, db, recover=False, port=None):
      
      if port is None:
          port = blockstack_opts['rpc_port']
  
      # start atlas node
      atlas_state = None
      if is_atlas_enabled(blockstack_opts):
          atlas_seed_peers = filter( lambda x: len(x) > 0, blockstack_opts['atlas_seeds'].split(","))
          atlas_blacklist = filter( lambda x: len(x) > 0, blockstack_opts['atlas_blacklist'].split(","))
          zonefile_dir = blockstack_opts['zonefiles']
          my_hostname = blockstack_opts['atlas_hostname']
          my_port = blockstack_opts['atlas_port']
  
          initial_peer_table = atlasdb_init(blockstack_opts['atlasdb_path'], zonefile_dir, db, atlas_seed_peers, atlas_blacklist, validate=True, recover=recover)
          atlas_peer_table_init(initial_peer_table)
  
          atlas_state = atlas_node_init(my_hostname, my_port, blockstack_opts['atlasdb_path'], zonefile_dir, db.working_dir)
  
      return atlas_state
docs: Start up atlas functionality