kubernetes/kops · error

error creating temp file in %q: %w

Error message

error creating temp file in %q: %w

What it means

WriteFile stages data in a temp file named .tmp-<random> inside the target directory, created via sftpClient.Create. If the SFTP server refuses to create that temp file, this error wraps the cause. It indicates the directory exists (mkdirAll passed) but a new file cannot be created there.

Source

Thrown at util/pkg/vfs/sshfs.go:188

func (p *SSHPath) WriteFile(ctx context.Context, data io.ReadSeeker, acl ACL) error {
	sftpClient, err := p.newClient(ctx)
	if err != nil {
		return err
	}
	defer sftpClient.Close()

	dir := path.Dir(p.path)
	err = mkdirAll(sftpClient, dir)
	if err != nil {
		return err
	}

	tempfile := path.Join(dir, fmt.Sprintf(".tmp-%d", rand.Int63()))
	f, err := sftpClient.Create(tempfile)
	if err != nil {
		// TODO: Retry if concurrently created?
		return fmt.Errorf("error creating temp file in %q: %w", dir, err)
	}

	// Note from here on in we have to close f and delete or rename the temp file
	shouldClose := true
	defer func() {
		if shouldClose {
			// Something went wrong; try to close the temp file
			if err := f.Close(); err != nil {
				klog.Warningf("unable to close temp file %q: %v", tempfile, err)
			}
		}
	}()

	deleteTempFile := true
	defer func() {
		if deleteTempFile {
			// Something went wrong; try to remove the temp file
			if err := sftpClient.Remove(tempfile); err != nil {

View on GitHub (pinned to 4c8573c808)

Solutions

1. Check free disk space on the remote host (`df -h <dir>`) and free space if full.
2. Verify the SSH user has write permission on the directory; `sudo chown`/`chmod` it or pre-create writable staging.
3. If an old .tmp-* file blocks creation (stale from a crashed run), remove it: `rm <dir>/.tmp-*`.
4. Retry — the comment notes concurrent creation is possible; the random suffix makes collisions unlikely.

Example fix

// before: full disk on remote host
Filesystem / has 0 available
// after
$ ssh host 'rm -rf /var/log/journal/*old*' && kops replace ... # retry succeeds

// verify disk space and writability on the remote directory before writing
out := sshRun(host, fmt.Sprintf("df --output=avail -B1 %s | tail -1; test -w %s && echo ok", dir, dir))
// require available > neededBytes and "ok" present

err := path.WriteFile(ctx, data, acl)
if err != nil && strings.Contains(err.Error(), "error creating temp file") {
    // clean stale temp files then retry once
    sshRun(host, fmt.Sprintf("rm -f %s/.tmp-*", dir))
    return path.WriteFile(ctx, data, acl)
}

When it happens

Trigger: WriteFile on an SSHPath where the directory is not writable by the SFTP user, the disk is full, or (rarely) the random temp name collides with an existing file that cannot be opened for writing.

Common situations: Writing node bootstrap files to /etc/kubernetes/manifests with a non-root SFTP user; full disk on the master node; immutable directory; SFTP chroot/subsystem restricting writes to certain paths.

Related errors

• not a directory: %q
• error writing temp file: %v
• error reading SSH public key %v: %v
• error reading /var/log: %v
• error listing %q: %v

AI-assisted analysis of kubernetes/kops@4c8573c808 (2026-09-05). Data as JSON: /api/errors/e4d829d9f972a533. Report an issue: GitHub.