What causes "either RequiredBytes or LimitBytes must be set" in hashicorp/nomad?

Set required_bytes (minimum size) and/or limit_bytes (maximum size) in the capacity_range block

either RequiredBytes or LimitBytes must be set

Error message

either RequiredBytes or LimitBytes must be set

What it means

CapacityRange.Validate in plugins/csi/plugin.go:1028 enforces the CSI spec's requirement that a capacity range must constrain the volume size on at least one bound. If both RequiredBytes and LimitBytes are zero, the range conveys no capacity information, so the request is rejected before reaching the CSI plugin.

Source

Thrown at plugins/csi/plugin.go:1028

		vc.AccessType = &csipbv1.VolumeCapability_Mount{Mount: opts}
	} else {
		vc.AccessType = &csipbv1.VolumeCapability_Block{Block: &csipbv1.VolumeCapability_BlockVolume{}}
	}

	return vc
}

type CapacityRange struct {
	RequiredBytes int64
	LimitBytes    int64
}

func (c *CapacityRange) Validate() error {
	if c == nil {
		return nil
	}
	if c.RequiredBytes == 0 && c.LimitBytes == 0 {
		return errors.New("either RequiredBytes or LimitBytes must be set")
	}
	if c.LimitBytes > 0 && c.LimitBytes < c.RequiredBytes {
		return errors.New("LimitBytes cannot be less than RequiredBytes")
	}
	return nil
}

func (c *CapacityRange) ToCSIRepresentation() *csipbv1.CapacityRange {
	if c == nil {
		return nil
	}
	return &csipbv1.CapacityRange{
		RequiredBytes: c.RequiredBytes,
		LimitBytes:    c.LimitBytes,
	}
}

type NodeExpandVolumeRequest struct {

View on GitHub (pinned to 482b49bf1a)

Solutions

Set required_bytes (minimum size) and/or limit_bytes (maximum size) in the capacity_range block
If no capacity constraint is intended, pass a nil CapacityRange rather than a zero-valued one
Validate the volume spec with nomad volume validate before submission

Example fix

// before
capacity_range {}
// after
capacity_range {
  required_bytes = 1073741824
  limit_bytes    = 2147483648
}

Defensive patterns

Strategy: validation

Validate before calling

if cr != nil && cr.RequiredBytes == 0 && cr.LimitBytes == 0 { return errors.New("capacity_range must set required_bytes or limit_bytes") }

Type guard

func hasCapacity(c *csi.CapacityRange) bool { return c == nil || c.RequiredBytes != 0 || c.LimitBytes != 0 }

Prevention

Always set required_bytes in volume specs
Use nomad volume validate before submit
Don't pass zero-valued structs; pass nil if unconstrained

When it happens

Trigger: Submitting a volume-create or volume-expand (NodeExpandVolumeRequest) request whose capacity_range stanza has neither required_bytes nor limit_bytes set; an empty or omitted capacity_range struct passed non-nil with zero values.

Common situations: Nomad volume spec (HCL/JSON) missing required_bytes under capacity_range; API clients constructing CSI volume requests programmatically and forgetting to set bytes; default-constructed Go structs passed to Validate.

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/f19de084999efa85. Report an issue: GitHub.