jax-ml/jax · error · ValueError

coordinator_bind_address should be defined.

Error message

coordinator_bind_address should be defined.

What it means

The coordinator's bind address must resolve to a concrete host:port. When it is not provided and JAX_COORDINATOR_BIND_ADDRESS is unset, initialize falls back to '[::]:<port from coordinator_address>'; if that still yields None (only possible via explicit None after env lookup), this ValueError fires.

Source

Thrown at jax/_src/distributed.py:161

      raise TypeError("process_id must be a nonnegative int. "
                      f"Got process_id={process_id} of type {type(process_id)}.")
    if not isinstance(num_processes, int):
      raise TypeError("num_processes must be a positive int. "
                      f"Got num_processes={num_processes} of type {type(num_processes)}.")
    if not (0 <= process_id < num_processes):
      raise ValueError("process_id and num_processes must be nonnegative, with process_id < num_processes. "
                       f"Got process_id={process_id}, num_processes={num_processes}.")

    self.coordinator_address = coordinator_address

    # The default value of [::]:port tells the coordinator to bind to all
    # available addresses on the same port as coordinator_address.
    default_coordinator_bind_address = '[::]:' + coordinator_address.rsplit(':', 1)[1]
    coordinator_bind_address = (coordinator_bind_address or
                                os.environ.get('JAX_COORDINATOR_BIND_ADDRESS',
                                               default_coordinator_bind_address))
    if coordinator_bind_address is None:
      raise ValueError('coordinator_bind_address should be defined.')

    if local_device_ids:
      visible_devices = ','.join(str(x) for x in local_device_ids)
      logger.info('JAX distributed initialized with visible devices: %s', visible_devices)
      config.update("jax_cuda_visible_devices", visible_devices)
      config.update("jax_rocm_visible_devices", visible_devices)

    self.process_id = process_id

    proxy_vars = []
    if _CHECK_PROXY_ENVS.value:
      proxy_vars = [key for key in os.environ.keys()
                    if '_proxy' in key.lower()]

    if len(proxy_vars) > 0:
      vars = " ".join(proxy_vars) + ". "
      warning = (
        f'JAX detected proxy variable(s) in the environment as distributed setup: {vars}'

View on GitHub (pinned to 1e1c6a8fc0)

Solutions

  1. Pass a valid bind address: coordinator_bind_address='0.0.0.0:12345'
  2. Set JAX_COORDINATOR_BIND_ADDRESS env var on the coordinator process
  3. Ensure coordinator_address includes a port so the default '[::]:port' derivation works

Example fix

# before
jax.distributed.initialize(coordinator_address='10.0.0.1', ...)
# after
jax.distributed.initialize(coordinator_address='10.0.0.1:12345',
    coordinator_bind_address='0.0.0.0:12345', ...)
Defensive patterns

Strategy: validation

Validate before calling

import os
bind = os.environ.get('JAX_COORDINATOR_BIND_ADDRESS') or '0.0.0.0:12345'
assert ':' in bind and bind.rsplit(':',1)[1].isdigit(), f'bad bind {bind}'

Prevention

When it happens

Trigger: Passing coordinator_bind_address=None explicitly while JAX_COORDINATOR_BIND_ADDRESS is unset and the default derivation path is bypassed; malformed coordinator_address without a port making the derived default unusable.

Common situations: Containerized coordinators with restrictive networking where operators pass explicit None expecting auto-detection; IPv4-only environments needing a specific bind address instead of the [::] wildcard; port stripped by address parsing bugs.

Understand the failure class

Background: "X is required", "must be set", "cannot be empty": the missing-required-config error family, from Vertex AI project/location to WeChat keys — this error's family across 18 libraries.

Related errors

AI-assisted analysis of jax-ml/jax@1e1c6a8fc0 (2026-08-27). Data as JSON: /api/errors/e8da2a80da9c22aa. Report an issue: GitHub.