hashicorp/nomad · error

minimum file size is 1MB; got %d

Error message

minimum file size is 1MB; got %d

What it means

Raised by LogConfig.Validate in nomad/structs/structs.go:7898 when MaxFileSizeMB < 1. Each rotated log file must be at least 1 MB, so Nomad rejects log configs with a zero or negative max_file_size. Like the max_files check, this is enforced at job validation time because non-zero defaults cannot be distinguished from explicit unset values.

Source

Thrown at nomad/structs/structs.go:7898

// DefaultLogConfig returns the default LogConfig values.
func DefaultLogConfig() *LogConfig {
	return &LogConfig{
		MaxFiles:      10,
		MaxFileSizeMB: 10,
		Disabled:      false,
	}
}

// Validate returns an error if the log config specified are less than the
// minimum allowed. Note that because we have a non-zero default MaxFiles and
// MaxFileSizeMB, we can't validate that they're unset if Disabled=true
func (l *LogConfig) Validate(disk *EphemeralDisk) error {
	var mErr multierror.Error
	if l.MaxFiles < 1 {
		mErr.Errors = append(mErr.Errors, fmt.Errorf("minimum number of files is 1; got %d", l.MaxFiles))
	}
	if l.MaxFileSizeMB < 1 {
		mErr.Errors = append(mErr.Errors, fmt.Errorf("minimum file size is 1MB; got %d", l.MaxFileSizeMB))
	}
	if disk != nil {
		logUsage := (l.MaxFiles * l.MaxFileSizeMB)
		if disk.SizeMB <= logUsage {
			mErr.Errors = append(mErr.Errors,
				fmt.Errorf("log storage (%d MB) must be less than requested disk capacity (%d MB)",
					logUsage, disk.SizeMB))
		}
	}
	return mErr.ErrorOrNil()
}

// Task is a single process typically that is executed as part of a task group.
type Task struct {
	// Name of the task
	Name string

	// Driver is used to control which driver is used

View on GitHub (pinned to 482b49bf1a)

Solutions

1. Set max_file_size >= 1 (MB) in the logs block (default is 10).
2. Use the default 10 MB if unsure by removing the max_file_size line.
3. Disable logging via the proper disabled mechanism rather than shrinking the size to 0.

Example fix

// before
logs {
  max_files     = 10
  max_file_size = 0
}
// after
logs {
  max_files     = 10
  max_file_size = 10
}

if t.LogConfig != nil && t.LogConfig.MaxFileSizeMB < 1 {
  return fmt.Errorf("max_file_size must be >= 1 MB, got %d", t.LogConfig.MaxFileSizeMB)
}

func validLogSizeMB(n *int) bool { return n != nil && *n >= 1 }

When it happens

Trigger: logs block with max_file_size = 0 or negative; LogConfig{MaxFileSizeMB: 0} passed to Validate; job submissions over the HTTP/RPC API carrying max_file_size < 1.

Common situations: Users set max_file_size = 0 hoping for unlimited or disabled logs; unit confusion (expecting bytes instead of MB) leading to values like 0; generated job specs filling 0 for optional integer fields.

Understand the failure class

Background: "Invalid value" and "allowed values are" config errors: what your library rejected and how to fix it — this error's family across 41 libraries.

Related errors

• Missing Log Config
• minimum number of files is 1; got %d
• Disconnect cannot be configured with both lost_after and sto
• lost_after cannot be a negative duration
• stop_after cannot be a negative duration

AI-assisted analysis of hashicorp/nomad@482b49bf1a (2026-09-04). Data as JSON: /api/errors/506a5331c867605d. Report an issue: GitHub.