hashicorp/nomad · error

missing volume definition

Error message

missing volume definition

What it means

Guard in the CSIVolume.Register RPC: the request contains no volume specifications (args.Volumes empty); registering volumes requires at least one volume definition.

Source

Thrown at nomad/csi_endpoint.go:297

	if authErr != nil {
		return structs.ErrPermissionDenied
	}

	allowVolume := acl.NamespaceValidator(acl.NamespaceCapabilityCSIWriteVolume)
	aclObj, err := v.srv.ResolveACL(args)
	if err != nil {
		return err
	}

	defer metrics.MeasureSince([]string{"nomad", "volume", "register"}, time.Now())

	// permission for the volume namespaces will be checked below
	if !aclObj.AllowPluginRead() {
		return structs.ErrPermissionDenied
	}

	if len(args.Volumes) == 0 {
		return fmt.Errorf("missing volume definition")
	}

	snap, err := v.srv.State().Snapshot()
	if err != nil {
		return err
	}

	// Validate ACLs, that the plugin exists for each volume, and validate the
	// capabilities when the plugin has a controller.
	for _, vol := range args.Volumes {
		if vol.Namespace == "" {
			vol.Namespace = args.RequestNamespace()
		}
		if !allowVolume(aclObj, vol.Namespace) {
			return structs.ErrPermissionDenied
		}
		// Check if override is set and we do not have permissions
		if args.PolicyOverride {

View on GitHub (pinned to 482b49bf1a)

Solutions

  1. Provide a valid volume definition in the request body (args.Volumes)
  2. Check the spec file path and content passed to nomad volume register
  3. Validate the spec parses to at least one volume before calling the API

Example fix

// before
nomad volume register empty.hcl
// after
nomad volume register volume.hcl  // file contains a 'volume' stanza
Defensive patterns

Strategy: validation

Validate before calling

if len(args.Volumes) == 0 {
    return errors.New("at least one volume definition required")
}

Try / catch

if err != nil && strings.Contains(err.Error(), "missing volume definition") { check spec file }

Prevention

When it happens

Trigger: Calling the CSIVolumeRegister RPC / volume register API with args.Volumes empty, e.g. an HCL/JSON spec that parsed to zero volumes.

Common situations: Passing an empty or mis-parsed volume spec file to nomad volume register; scripting the API with an empty list; wrong filename or file containing no volume stanza.

Understand the failure class

Background: "missing required argument" and "the following required arguments were not provided": what required-argument errors mean and how to fix them — this error's family across 20 libraries.

Related errors

AI-assisted analysis of hashicorp/nomad@482b49bf1a (2026-09-04). Data as JSON: /api/errors/43c491a6d101b626. Report an issue: GitHub.