hashicorp/nomad · error

could not create default configuration file - %s

Error message

could not create default configuration file - %s

What it means

If the config directory is empty (no glob matches), configInstall seeds it with a default config.hcl via os.Create. This error wraps failure of that file creation — the directory exists but the file could not be opened for writing. The install aborts with no default configuration written.

Source

Thrown at command/windows_service_install.go:278

	if opts.dataDir, err = c.winPaths.Expand(opts.dataDir); err != nil {
		return fmt.Errorf("cannot generate data path - %s", err)
	}

	// Ensure directories exist
	if err = c.winPaths.CreateDirectory(opts.configDir, true); err != nil {
		return fmt.Errorf("cannot create configuration directory - %s", err)
	}

	if err = c.winPaths.CreateDirectory(opts.dataDir, true); err != nil {
		return fmt.Errorf("cannot create data directory - %s", err)
	}

	// Check if any configuration files exist
	matches, _ := filepath.Glob(filepath.Join(opts.configDir, "*"))
	if len(matches) < 1 {
		f, err := os.Create(filepath.Join(opts.configDir, "config.hcl"))
		if err != nil {
			return fmt.Errorf("could not create default configuration file - %s", err)
		}
		fmt.Fprintf(f, strings.TrimSpace(`
# Full configuration options can be found at https://developer.hashicorp.com/nomad/docs/configuration

data_dir  = "%s"
bind_addr = "0.0.0.0"

server {
  # license_path is required for Nomad Enterprise as of Nomad v1.1.1+
  #license_path = "%s\license.hclic"
  enabled          = true
  bootstrap_expect = 1
}

client {
  enabled = true
  servers = ["127.0.0.1"]
}

View on GitHub (pinned to 482b49bf1a)

Solutions

1. Run the installer from an elevated (Administrator) prompt
2. Manually pre-create config.hcl in the config dir with valid Nomad configuration (then the seed step is skipped)
3. Check ACLs on the config directory (icacls) and grant the installing user write access
4. Verify antivirus is not blocking file creation and disk has space

Example fix

// before: let installer seed file, fails on ACLs
nomad windows service install
// after: pre-create the config yourself
// C:\> Set-Content C:\ProgramData\nomad\config.hcl 'data_dir = "C:/ProgramData/nomad/data"'
// C:\> nomad windows service install

// Pre-check that config.hcl can be created in the target dir
probe := filepath.Join(configDir, ".nomad_probe")
if err := os.WriteFile(probe, nil, 0o600); err != nil {
    return fmt.Errorf("config dir not writable: %w", err)
}
os.Remove(probe)

When it happens

Trigger: Running 'nomad windows service install' into an empty-but-unwritable config dir: ACL denies write to the installing user, the directory is on read-only media, antivirus locks config.hcl, or path/quota issues.

Common situations: Installing as a non-admin user into a directory owned by another account; Group Policy-restricted ProgramData ACLs; antivirus intercepting new .hcl files; disk full.

Understand the failure class

Background: "Permission denied" / "Failed to write" file errors: why a library can't write its files to disk (EACCES, EPERM, ENOSPC) and how to fix them — this error's family across 43 libraries.

Related errors

• service registration check failed - %w
• unable to create service - %w
• cannot create configuration directory - %s
• cannot create data directory - %s
• could not create binary install directory - %s

AI-assisted analysis of hashicorp/nomad@482b49bf1a (2026-09-04). Data as JSON: /api/errors/ea992395d79fd424. Report an issue: GitHub.