hashicorp/nomad · error

invalid hook: %v

Error message

invalid hook: %v

What it means

TaskLifecycleConfig.Validate() accepts only the three known hooks: prestart, poststart, poststop. Any other non-empty `hook` string hits the default branch and produces this error with the invalid value interpolated.

Source

Thrown at nomad/structs/structs.go:6189

	}
	nd := new(TaskLifecycleConfig)
	*nd = *d
	return nd
}

func (d *TaskLifecycleConfig) Validate() error {
	if d == nil {
		return nil
	}

	switch d.Hook {
	case TaskLifecycleHookPrestart:
	case TaskLifecycleHookPoststart:
	case TaskLifecycleHookPoststop:
	case "":
		return fmt.Errorf("no lifecycle hook provided")
	default:
		return fmt.Errorf("invalid hook: %v", d.Hook)
	}

	return nil
}

var (
	// These default restart policies needs to be in sync with
	// Canonicalize in api/tasks.go

	DefaultServiceJobRestartPolicy = RestartPolicy{
		Delay:           15 * time.Second,
		Attempts:        2,
		Interval:        30 * time.Minute,
		Mode:            RestartPolicyModeFail,
		RenderTemplates: false,
	}
	DefaultBatchJobRestartPolicy = RestartPolicy{
		Delay:           15 * time.Second,

View on GitHub (pinned to 482b49bf1a)

Solutions

1. Use exactly one of `prestart`, `poststart`, or `poststop` (lowercase) for `hook`.
2. Check `nomad job validate <file>` output — it echoes the invalid value to identify the typo.
3. Verify the Nomad version supports the intended hook (all three exist in supported versions; there is no 'prerestart').

Example fix

// before
lifecycle {
  hook = "pre-start"
}
// after
lifecycle {
  hook = "prestart"
}

var validHooks = map[string]bool{"prestart": true, "poststart": true, "poststop": true}
if !validHooks[lc.Hook] {
	return fmt.Errorf("invalid hook %q; use prestart|poststart|poststop", lc.Hook)
}

When it happens

Trigger: Setting `hook` to a misspelled or unsupported value such as `pre-start`, `PresTart`, `restart`, or `stop` in a task's lifecycle block, then running `nomad job run` or a plan/validate call.

Common situations: Typos or wrong casing; confusing Nomad lifecycle hooks with Docker/systemd hook names; following outdated documentation or examples from other schedulers.

Understand the failure class

Background: Invalid enum value errors: "Unknown type", "Invalid scope", "must be one of" — when a string is not on the library's allowed list — this error's family across 23 libraries.

Related errors

• no lifecycle hook provided
• Disconnect cannot be configured with both lost_after and sto
• lost_after cannot be a negative duration
• stop_after cannot be a negative duration
• Missing job ID

AI-assisted analysis of hashicorp/nomad@482b49bf1a (2026-09-04). Data as JSON: /api/errors/6c8e15f65cfe7c72. Report an issue: GitHub.