hashicorp/nomad · error

Task name cannot include slashes

Error message

Task name cannot include slashes

What it means

Task.Validate rejects task names containing '/' or '\\' because the task name becomes a directory on disk under the allocation directory; slashes would create nested or invalid paths. The check uses strings.ContainsAny on the name.

Source

Thrown at nomad/structs/structs.go:8242

	return fmt.Sprintf("*%#v", *t)
}

// Validate is used to check a task for reasonable configuration
func (t *Task) Validate(jobType string, tg *TaskGroup) error {
	var mErr multierror.Error
	if t.Name == "" {
		mErr.Errors = append(mErr.Errors, errors.New("Missing task name"))
	}

	// Tasks cannot be named "alloc" as this conflicts with and breaks task
	// filesystem isolation features.
	if t.Name == "alloc" {
		mErr.Errors = append(mErr.Errors, errors.New("Task cannot be named \"alloc\""))
	}
	if strings.ContainsAny(t.Name, `/\`) {
		// We enforce this so that when creating the directory on disk it will
		// not have any slashes.
		mErr.Errors = append(mErr.Errors, errors.New("Task name cannot include slashes"))
	} else if strings.Contains(t.Name, "\000") {
		mErr.Errors = append(mErr.Errors, errors.New("Task name cannot include null characters"))
	}
	if t.Driver == "" {
		mErr.Errors = append(mErr.Errors, errors.New("Missing task driver"))
	}
	if t.KillTimeout < 0 {
		mErr.Errors = append(mErr.Errors, errors.New("KillTimeout must be a positive value"))
	} else {
		// Validate the group's update strategy does not conflict with the
		// task's kill_timeout for service jobs.
		//
		// progress_deadline = 0 has a special meaning so it should not be
		// validated against the task's kill_timeout.
		conflictsWithProgressDeadline := jobType == JobTypeService &&
			tg.Update != nil &&
			tg.Update.ProgressDeadline > 0 &&
			t.KillTimeout > tg.Update.ProgressDeadline

View on GitHub (pinned to 482b49bf1a)

Solutions

1. Remove slashes from the task name (use "-" or "_" instead).
2. Sanitize names in job-generation scripts.
3. Validate before submit.

Example fix

// before
task "web/server" {
  driver = "docker"
}
// after
task "web-server" {
  driver = "docker"
}

if strings.ContainsAny(t.Name, `/\\`) {
  return fmt.Errorf("task name %q must not contain slashes", t.Name)
}

func isPathSafeName(t *structs.Task) bool {
  return !strings.ContainsAny(t.Name, `/\\`)
}

When it happens

Trigger: A task name containing a forward or back slash, e.g. task "web/server" or names derived from file paths or container image names.

Common situations: Deriving the task name from a repo path or image tag; Windows-style separators in generated configs.

Related errors

• Missing task name
• Task cannot be named "alloc"
• Task name cannot include null characters
• Missing task driver
• KillTimeout must be a positive value

AI-assisted analysis of hashicorp/nomad@482b49bf1a (2026-09-04). Data as JSON: /api/errors/d8d62153fcef3574. Report an issue: GitHub.