docker/cli · error

failed to write the container ID

Error message

failed to write the container ID (%s) to file: %w

What it means

Returned by cidFile.Write(id) when writing the container ID string to the already-created CID file fails (cli/command/container/create.go:190-192). The file was opened by os.Create in newCIDFile; a write failure after the container was successfully created (ENOSPC, EROFS, EIO, or the fd invalidated) is wrapped with the actual ID that could not be persisted.

Solutions

1. Free disk space on the target volume and retry.
2. Point --cidfile at a local, writable filesystem (not a near-full or read-only mount).
3. Record the container ID printed by the daemon by other means if the CID file cannot be written.
4. Ensure no external tooling locks/deletes the CID file mid-run.

Example fix

# before
docker create --cidfile /full-disk/cid myimage   # write fails: ENOSPC
# after
docker create --cidfile /tmp/cid myimage

if err := cidFile.Write(id); err != nil {
    // container was created; record id via fallback (e.g. log) since the file write failed
}

When it happens

Trigger: Using --cidfile <path>, the container is created and Write(id) is invoked, but file.WriteString(id) fails. The container exists on the daemon, but the ID could not be recorded to disk.

Common situations: Disk full (ENOSPC) on the volume holding the CID file, the filesystem remounted read-only, a network filesystem write error, or the file descriptor invalidated (e.g. file deleted and reopened weirdly by an external tool).

Related errors

• container ID file found, make sure the other container…
• failed to remove the CID file
• failed to create the container ID file
• failed to write public key to
• source can not be empty

AI-assisted analysis of docker/cli@4f84911bfe (2026-08-07). Data as JSON: /api/errors/77c4f31c93ed34b7. Report an issue: GitHub.

Appendix: source

Thrown at cli/command/container/create.go:191

	}
	_ = cid.file.Close()

	if cid.written {
		return nil
	}
	if err := os.Remove(cid.path); err != nil && !errors.Is(err, os.ErrNotExist) {
		return fmt.Errorf("failed to remove the CID file: %w", err)
	}

	return nil
}

func (cid *cidFile) Write(id string) error {
	if cid.file == nil {
		return nil
	}
	if _, err := cid.file.WriteString(id); err != nil {
		return fmt.Errorf("failed to write the container ID (%s) to file: %w", id, err)
	}
	cid.written = true
	return nil
}

func newCIDFile(cidPath string) (*cidFile, error) {
	if cidPath == "" {
		return &cidFile{}, nil
	}
	if _, err := os.Stat(cidPath); err == nil {
		return nil, errors.New("container ID file found, make sure the other container isn't running or delete " + cidPath)
	}

	f, err := os.Create(cidPath)
	if err != nil {
		return nil, fmt.Errorf("failed to create the container ID file: %w", err)
	}

View on GitHub (pinned to 4f84911bfe)