hashicorp/nomad · error

invalid capacity: %v

Error message

invalid capacity: %v

What it means

After HCL decoding, decodeHostVolume parses the `capacity` block/attribute with parseCapacityBytes. If that helper fails (missing value, unparsable size string, negative or non-integer bytes), the error is wrapped with `invalid capacity: %v`. The original parseCapacityBytes message is preserved after the prefix.

Source

Thrown at command/volume_create_host.go:242

	}

	// Need to manually parse these fields/blocks
	delete(m, "capability")
	delete(m, "constraint")
	delete(m, "capacity")
	delete(m, "capacity_max")
	delete(m, "capacity_min")
	delete(m, "type")

	// Decode the rest
	err = mapstructure.WeakDecode(m, vol)
	if err != nil {
		return nil, err
	}

	capacity, err := parseCapacityBytes(list.Filter("capacity"))
	if err != nil {
		return nil, fmt.Errorf("invalid capacity: %v", err)
	}
	vol.CapacityBytes = capacity
	capacityMin, err := parseCapacityBytes(list.Filter("capacity_min"))
	if err != nil {
		return nil, fmt.Errorf("invalid capacity_min: %v", err)
	}
	vol.RequestedCapacityMinBytes = capacityMin
	capacityMax, err := parseCapacityBytes(list.Filter("capacity_max"))
	if err != nil {
		return nil, fmt.Errorf("invalid capacity_max: %v", err)
	}
	vol.RequestedCapacityMaxBytes = capacityMax

	if o := list.Filter("constraint"); len(o.Items) > 0 {
		if err := parseConstraints(&vol.Constraints, o); err != nil {
			return nil, fmt.Errorf("invalid constraint: %v", err)
		}
	}

View on GitHub (pinned to 482b49bf1a)

Solutions

1. Use an accepted byte-size string, e.g. `capacity = "10GiB"` or `capacity = "500GB"`
2. Check the exact inner error after `invalid capacity:` — it names the underlying parse failure
3. Remove commas/underscores/whitespace from the number; use plain digits plus a unit suffix
4. If capacity should be omitted, delete the key rather than setting it to an empty string

Example fix

// before
capacity = "10 Gi"

// after
capacity = "10GiB"

func validCapacity(s string) error {
	if _, err := units.RAMInBytes(s); err != nil {
		return fmt.Errorf("capacity %q is not a valid byte size: %v", s, err)
	}
	return nil
}
// validate each capacity field before writing/submitting the spec

_, err := parseCapacityBytes(list.Filter("capacity"))
if err != nil {
	return fmt.Errorf("fix `capacity` in the volume spec to a size like 10GiB: %v", err)
}

When it happens

Trigger: `nomad volume create` with a host volume HCL spec containing a `capacity` key whose value cannot be parsed as a byte size (e.g. `capacity = "ten GiB"`, `capacity = "-5GB"`, or an empty block).

Common situations: Typos in unit suffixes ("10Gi", "10 gibs"), using SI/binary prefixes Nomad doesn't accept, localizing numbers ("10,5 GB"), or forgetting the value entirely.

Related errors

• invalid capacity_min: %v
• invalid capacity_max: %v
• <combined HCL diagnostics from str.String()>
• invalid variables limit: %v
• %s must be integer; got (%T) %[2]v

AI-assisted analysis of hashicorp/nomad@482b49bf1a (2026-09-04). Data as JSON: /api/errors/cfc888894d925fe9. Report an issue: GitHub.