bigchaindb: BigchainDB docker connect failed

requests.exceptions.ConnectionError: HTTPConnectionPool(host=‘bdb-server’, port=9984): Max retries exceeded with url: /api/v1/transactions/ (Caused by NewConnectionError(‘<requests.packages.urllib3.connection.HTTPConnection object at 0x10263d470>: Failed to establish a new connection: [Errno 8] nodename nor servname provided, or not known’,))

from bigchaindb_driver import BigchainDB
from bigchaindb_driver.crypto import generate_keypair
bdb = BigchainDB('http://bdb-server:9984')


bicycle = {
  'data': {
    'bicycle': {
      'serial_number': 'abcd1234',
      'manufacturer': 'bkfab',
    },
  },
}

metadata = {'planet': 'earth'}

alice, bob = generate_keypair(), generate_keypair()


prepared_creation_tx = bdb.transactions.prepare(
       operation='CREATE',
       signers=alice.public_key,
       asset=bicycle,
       metadata=metadata,
   )




fulfilled_creation_tx = bdb.transactions.fulfill(prepared_creation_tx, private_keys=alice.private_key)

print(fulfilled_creation_tx)

sent_creation_tx = bdb.transactions.send(fulfilled_creation_tx)