tensorflow/models · error · ValueError

Must specify task_index when number of workers > 1

Error message

Must specify task_index when number of workers > 1

What it means

Error "Must specify task_index when number of workers > 1" thrown in tensorflow/models.

Source

Thrown at official/common/distribute_utils.py:226

  """Set multi-worker cluster spec in TF_CONFIG environment variable.

  Args:
    worker_hosts: comma-separated list of worker ip:port pairs.
    task_index: index of the worker.

  Returns:
    Number of workers in the cluster.
  """
  tf_config = json.loads(os.environ.get("TF_CONFIG", "{}"))
  if tf_config:
    num_workers = (
        len(tf_config["cluster"].get("chief", [])) +
        len(tf_config["cluster"].get("worker", [])))
  elif worker_hosts:
    workers = worker_hosts.split(",")
    num_workers = len(workers)
    if num_workers > 1 and task_index < 0:
      raise ValueError("Must specify task_index when number of workers > 1")
    task_index = 0 if num_workers == 1 else task_index
    os.environ["TF_CONFIG"] = json.dumps({
        "cluster": {
            "worker": workers
        },
        "task": {
            "type": "worker",
            "index": task_index
        }
    })
  else:
    num_workers = 1
  return num_workers


def get_strategy_scope(strategy):
  if strategy:
    strategy_scope = strategy.scope()

View on GitHub (pinned to e006f5f0d5)

When it happens

Trigger: Thrown at official/common/distribute_utils.py:226 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of tensorflow/models@e006f5f0d5 (2026-08-24). Data as JSON: /api/errors/1d1af2d36d78af20. Report an issue: GitHub.