What causes "Task %d missing name" in hashicorp/nomad?

Add a unique, non-empty `name` to each task block in the group.

Task %d missing name

Error message

Task %d missing name

What it means

During TaskGroup.Validate, every task in the group must have a non-empty `name`. When a task is found with an empty name, Nomad appends this error (1-indexed by position in the group) to the job's multierror, since unnamed tasks cannot be scheduled, referenced by services, or reported on.

Source

Thrown at nomad/structs/structs.go:7254

	case JobTypeService:
		if tg.Migrate != nil {
			if err := tg.Migrate.Validate(); err != nil {
				mErr = multierror.Append(mErr, err)
			}
		}
	default:
		if tg.Migrate != nil {
			mErr = multierror.Append(mErr, fmt.Errorf("Job type %q does not allow migrate block", j.Type))
		}
	}

	// Check that there is only one leader task if any
	tasks := make(map[string]int)
	leaderTasks := 0
	mainTasks := 0
	for idx, task := range tg.Tasks {
		if task.Name == "" {
			mErr = multierror.Append(mErr, fmt.Errorf("Task %d missing name", idx+1))
		} else if existing, ok := tasks[task.Name]; ok {
			mErr = multierror.Append(mErr, fmt.Errorf("Task %d redefines '%s' from task %d", idx+1, task.Name, existing+1))
		} else {
			tasks[task.Name] = idx
		}

		if task.Leader {
			leaderTasks++
		}

		if task.IsMain() {
			mainTasks++
		}
	}

	if leaderTasks > 1 {
		mErr = multierror.Append(mErr, fmt.Errorf("Only one task may be marked as leader"))
	}

View on GitHub (pinned to 482b49bf1a)

Solutions

Add a unique, non-empty `name` to each task block in the group.
If generating the job via the SDK/API, set the Name field explicitly before submission.

Example fix

// before
task "" {
  driver = "docker"
}
// after
task "myapp" {
  driver = "docker"
}

Defensive patterns

Strategy: validation

Validate before calling

// Go: check task names before submission
for _, tg := range job.TaskGroups {
  for i, t := range tg.Tasks {
    if t.Name == "" {
      return fmt.Errorf("group %q task %d: name is required", tg.Name, i+1)
    }
  }
}

Prevention

Set task Name explicitly in SDK-generated jobs.
Guard templating variables that supply task names against empty values.
Run `nomad job validate` on generated specs before submit.

When it happens

Trigger: Submitting a job where a `task` block inside a group has no `name` field (empty string), typically from programmatic job construction or template substitution that dropped the name.

Common situations: Generating job specs in code/Golang SDK with an unset Task.Name; templating (e.g. `${task_name}` rendered empty); hand-edited HCL where the name line was deleted.

Related errors

AI-assisted analysis of hashicorp/nomad@482b49bf1a (2026-09-04). Data as JSON: /api/errors/69fa934618a19b23. Report an issue: GitHub.